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If a person runs around a track that is in the shape of a circle at 5 m/s without speeding up or slowing down, explain how they are accelerating even though they are not changing speed. (Be sure to write a full sentence)

Answer:

it must be possible to prove it wrong

Explanation:

Answer:

it must be possible to prove it wrong

Explanation:

Falsibiable is the word used to make the refernce that it is possible to prove something wrong or to prove that somthing is wrong with a statement ot hypothesis, since the hypothsesis is falsifiable it must be possible to prove it wrong, that is the correct answer.

Answer:

Electricity is the voltage produced by any electrical energy source such as battery or dynamo. EMF increase with distance.

The direct current is fixed but the alternating current is constantly changing

Answer:

[tex]2.84\cdot 10^{-8} m[/tex]

Explanation:

Due to the law of conservation of energy, the energy of the emitted X-ray photon is equal to the energy lost by the electron.

The initial kinetic energy of the electron is:

[tex]K_i = \frac{1}{2}mv_i^2 = \frac{1}{2}(9.11\cdot 10^{-31}kg)(5.90\cdot 10^6 m/s)^2=1.59\cdot 10^{-17}J[/tex]

The electrons decelerates to 3/4 of its speed, so the new speed is

[tex]v_f = \frac{3}{4}v_i = \frac{3}{4}(5.90\cdot 10^6 m/s)=4.425\cdot 10^6 m/s[/tex]

So the final kinetic energy is

[tex]K_f = \frac{1}{2}mv_f^2=\frac{1}{2}(9.11 \cdot 10^{-31} kg)(4.425\cdot 10^6 m/s)^2=8.9\cdot 10^{-18} J[/tex]

So, the energy lost by the electron, which is equal to the energy of the emitted photon, is

[tex]E=K_i - K_f =1.59\cdot 10^{-17} J-8.9\cdot 10^{-18} J=7\cdot 10^{-18} J[/tex]

The wavelength of the photon is related to its energy by

[tex]\lambda=\frac{hc}{E}[/tex]

where h is the Planck constant and c the speed of light. Substituting E, we find

[tex]\lambda=\frac{(6.63\cdot 10^{-34}Js)(3\cdot 10^8 m/s)}{7\cdot 10^{-18} J}=2.84\cdot 10^{-8} m[/tex]

To determine the wavelength of the photon emitted when an electron decelerates in an X-ray tube, we can use Planck's equation and the information given about the electron's speed.

When an electron decelerates, it emits electromagnetic waves known as X-rays. The wavelength of the X-ray photon can be determined using Planck's equation, E = hv, where E is energy, h is Planck's constant, and v is frequency. Given that the electron's velocity decreases to three-quarters of its original speed and the initial speed is 5.90x10^6 m/s, we can calculate the velocity of the electron after deceleration. Using this value, we can then calculate the wavelength of the photon emitted. Therefore, using the provided information, we can find the wavelength of the photon.

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Answer:

A. A line can be drawn from the planet to the sun that sweeps out equal areas in equal times

Explanation:

This is exactly what Kepler's second law of planetary motion states:

"the segment joining the sun with the center of each planet sweeps out equal areas in equal time"

This law basically tells how the speed of a planet orbiting the sun changes during its revolution. In fact, we have that:

- when a planet is closer to the Sun, it will orbit faster

- when a planet is farther from the Sun, it will orbit slower

Answer:

1440 W

Explanation:

First of all, we can find the total displacement of the sled, which is given by

[tex]d=\frac{1}{2}at^2[/tex]

where

a = 0.08 m/s^2 is the acceleration

t = 1 min = 60 s is the time

Substituting,

[tex]d=\frac{1}{2}(0.08 m/s^2)(60 s)^2=144 m[/tex]

Now we can find the wotk done on the sled, equal to the product between force and displacement:

[tex]W=Fd=(600 N)(144 m)=86,400 J[/tex]

And finally we can fidn the average power, which is the ratio between the work done and the time taken:

[tex]P=\frac{W}{t}=\frac{86,400 J}{60 s}=1440 W[/tex]

Answer:

it is a.health record documentation

Explanation:hope this helps

Answer: Reimbursement and research

Explanation: I got it right on the PF exam

Answer:

(B)

Explanation:

While some of the other scenarios make sense to match with Newton's Third Law of Motion, their reaction and actions are in the wrong order.

The scenario: An ax being used to hit wood (action) and the wood splitting after being hit by the ax (reaction), accurately names the correct action and reaction pair to apply to Newton's Third Law.

To find the correct option among all the options, we need to know about the Newton's third law.

Newton's third law of motion says that every action has a opposite and equal reaction.

Thus, we can conclude that the option (b) is correct.

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Answer:

[tex]4.8\cdot 10^{-15} N[/tex]

Explanation:

The force exerted on a charged particle by an electric field is:

[tex]F=qE[/tex]

where

q is the magnitude of the charge of the particle

E is the magnitude of the electric field

For an electron,

[tex]q=1.6\cdot 10^{-19} C[/tex]

while the magnitude of the electric field in the problem is

[tex]E=30000 V/m[/tex]

so, the electric force on the electron is

[tex]F=(1.6\cdot 10^{-19}C)(30000 V/m)=4.8\cdot 10^{-15} N[/tex]

Answer:

1, 2, 4, 6

Explanation:

Move the magnet forward.

Move the loop away from the magnet.

Move the loop sideways.

Rotate the loop in place.

Answer:

Explanation:

When a changing magnetic flux linked with the coil, then the induced emf or induced current is developed.

1. Move the magnet forward.

Here, the flux linked with the coil changes, so the induced current is developed.

2. Move the loop away from the magnet.

Here, the flux linked with the coil changes, so the induced current is developed.

3. Place the loop right next to the magnet, both stationary.

Here, the flux linked with the coil does not change, so the induced current is not developed.

4. Move the loop sideways.

Here, the flux linked with the coil changes, so the induced current is developed.

5. Move the magnet and loop in the same direction, at the same speed, at the same time.

Here, the flux linked with the coil does not change, so the induced current is not developed.

6. Rotate the loop in place.

Here, the flux linked with the coil changes, so the induced current is developed.

(a) 25 A

The induced emf in the circuit is given by

[tex]\epsilon = -\frac{\Delta \Phi}{\Delta t}[/tex]

where

[tex]\Delta Phi[/tex] is the variation of magnetic flux through the bracelet

[tex]\Delta t = 19.0 ms =0.019 s[/tex] is the time interval

The variation of magnetic flux is

[tex]\Delta \Phi = A \Delta B[/tex]

where

[tex]A=0.005 m^2[/tex] is the area enclosed by the bracelet

[tex]\Delta B=0.81 T-2.70 T=-1.89 T[/tex] is the change of magnetic field strength

So we find

[tex]\Delta \Phi = (0.005 m^2)(-1.89 T)=-9.45\cdot 10^{-3} Wb[/tex]

And so the induced emf is

[tex]\epsilon = -\frac{-9.45\cdot 10^{-3} Wb}{0.019 s}=0.50 V[/tex]

Since the resistance of the bracelet is

[tex]R=0.02\Omega[/tex]

the induced current is

[tex]I=\frac{V}{R}=\frac{0.50 V}{0.02 \Omega}=25 A[/tex]

(b) 12.5 W

The power delivered to the bracelet is given by

[tex]P=V I[/tex]

where we have

I = 25 A is the current

V = 0.50 V is the emf induced in the bracelet

Substituting numbers, we find

[tex]P=(0.50 V)(25 A)=12.5 W[/tex]

The problem involves using Faraday's Law to compute for the induced current and power in the bracelet due to a change in the magnetic field strength of the solenoid it is placed in.

This involves calculating the induced current (part a) and power (part b) in the bracelet due to a change in the magnetic field. This can be solved using Faraday's Law which states that the induced electromotive force (EMF) in a circuit is equal to the negative rate of change of magnetic flux. For part a, we compute for the EMF using the formula ΔΦ/Δt = (2.70 T - 0.81 T) * 0.00500 m²/0.019 s which can then be used to calculate the induced current by dividing the EMF by the resistance of the bracelet. Part b involves finding the delivered power using the formula P=I²R, where I is the induced current and R is the resistance.

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Statement C about electric and magnetic fields is true. Option C is correct.

It is the type of field where the magnetic force is obtained. With the help of a magnetic field. The magnetic force is obtained, it is the field felt around a moving electric charge.

There are two poles of the magnet;

1. North Pole.

2. South Pole.

It has two poles, one north, and one south, and when hanging freely, the magnet aligns itself such that the north pole faces the earth's magnetic north pole.

They point away from the north pole and towards the south pole, is the statement correctly describing magnetic field lines around a magnet.

Statement about electric and magnetic fields is true is;

Magnetic fields must start at the north pole of a magnet and end at the south pole of a magnet.

Hence, option C is correct.

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Answer:

Binding energy

Explanation:

The energy required to bind the nucleus is called binding energy.

Binding energy is equal to the product of mass defect and square of velocity of light.

Mass defect is the difference of mass of neucleons and the mass of atom.

Answer:

Binding Energy

Explanation:

(a) 646.9 Hz

The formula for the Doppler effect is:

[tex]f'=\frac{v+v_o}{v-v_s}f[/tex]

where

f = 600 Hz is the real frequency of the sound

f' is the apparent frequency

v = 345 m/s is the speed of sound

[tex]v_o = 0[/tex] is the velocity of the observer (zero since it is stationary at the station)

[tex]v_s = +25 m/s[/tex] is the velocity of the source (the train), moving toward the observer

Substituting into the formula,

[tex]f'=\frac{345 m/s+0}{345 m/s-25 m/s}(600 Hz)=646.9 Hz[/tex]

(b) 20.1 m/s

In this case, we have

f = 600 Hz is the real frequency

f' = 567 Hz is the apparent frequency

Assuming the observer is still at rest,

[tex]v_o = 0[/tex]

so we can re-arrange the Doppler formula to find [tex]v_s[/tex], the new velocity of the train:

[tex]f'=\frac{v}{v-v_s}f\\\frac{f}{f'}=\frac{v-v_s}{v}\\\frac{f}{f'}v=v-v_s\\v_s = (1-\frac{f}{f'})v=(1-\frac{600 Hz}{567 Hz})(345 m/s)=-20.1 m/s[/tex]

and the negative sign means the train is moving away from the observer at the station.

The observed frequency of the train's horn is 600 Hz for a stationary observer. As the train moves away, its speed is calculated to be approximately 14.81 m/s to yield an observed frequency of 567 Hz.

This question revolves around the principle of Doppler Effect in Physics. The Doppler Effect explains how observed frequency shifts depending on the relative motion of the source (in this case, a train) and the observer (a person at the station).

(a) As the train approaches the person, the frequency detected will be higher than the original. This can be calculated using the formula: f' = f((v + vo) / v), where f' is the observed frequency, f is the source frequency, v is the speed of sound, and vo is the observer's velocity. Since the observer is stationary, vo = 0. f' = 600 Hz * ((345 m/s + 0) / 345 m/s) = 600 Hz

(b) As the train moves away from the person, the observed frequency decreases. Use the formula: f' = f * (v / (v + vs)), where vs is the source's velocity. Solving for vs, we get vs = v - (v * f / f'), equals to 345 m/s - (345 m/s * 600 Hz / 567 Hz) = 14.81 m/s.

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(a) -4667 N

First of all, we can calculate the acceleration of the arm and the glove, using the following equation:

[tex]v^2 - u^2 = 2ad[/tex]

where

v = 0 is the final speed

u = 10 m/s is the initial speed

a is the acceleration

d = 7.50 cm = 0.075 m is the distance through which the arm and the glove move before coming to a stop

Solving for a,

[tex]a=\frac{v^2-u^2}{2d}=\frac{0-(10.0 m/s)^2}{2(0.075 m)}=-666.7 m/s^2[/tex]

And since the know the mass of the arm+glove:

m = 7.00 kg

We can now calculate the force exerted:

[tex]F=ma=(7.00 kg)(-666.7 N)=-4,667 N[/tex]

(b) -17500 N

We can repeat the problem, but this time the stopping distance is different:

d = 2.00 cm = 0.02 m

So the acceleration is

[tex]a=\frac{v^2-u^2}{2d}=\frac{0-(10.0 m/s)^2}{2(0.02 m)}=-2500 m/s^2[/tex]

and so the force is

[tex]F=ma=(7.00 kg)(-2500 m/s^2)=-17,500 N[/tex]

(c) Yes

The force exerted when the glove is used is

F = 4667 N

We see that this force corresponds approximately to the weight of an object of mass m=476 kg, in fact:

[tex]W=mg=(476 kg)(9.81 m/s^2)=4670 N[/tex]

Which is quite a lot. Therefore, the force even when gloves are used seems enough to cause damage.

To calculate the force exerted by a boxing glove on an opponent's face, we can use the equation for impulse.

In order to calculate the force exerted by a boxing glove on an opponent's face, we need to use the equation for impulse:

Impulse = change in momentum = force x time

We know the initial speed of the arm and glove (10.0 m/s), the final speed (0 m/s), and the time it takes for the glove and face to compress (which can be calculated using the distance and the initial speed).

By substituting these values into the equation, we can find the average force exerted by the boxing glove on the opponent's face.

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Answer: Mars

Explanation:

Mars is a planet similar to the earth which the rest can't sustain life either because it's too hot or cold or too much gas maybe even toxic acid.

Final answer:

Mars is the most likely planet other than Earth to have life in our solar system, based on past habitable conditions. The neighboring terrestrial planets, Venus and Mars, have evolved differently, with Earth being the most habitable. Gas giants like Jupiter and Saturn are not considered habitable.

Explanation:

Mars is currently thought to be the most likely planet, after Earth, to have life. Despite being colder and drier than Earth, Mars has shown evidence of habitable conditions in the past, making it a prime candidate for potential life forms.

Venus and Mars are the neighboring terrestrial planets diverged significantly in their evolution, with Earth being the most hospitable planet in the solar system. The outer gas giant planets like Jupiter and Saturn are almost certainly not habitable for life as we know it.

(a) 80 N/m

The spring constant can be found by using Hooke's law:

[tex]F=kx[/tex]

where

F is the force on the spring

k is the spring constant

x is the displacement of the spring relative to the equilibrium position

At the beginning, we have

F = 16.0 N is the force applied

x = 0.200 m is the displacement from the equilibrium position

Solving the formula for k, we find

[tex]k=\frac{F}{m}=\frac{16.0 N}{0.200 m}=80 N/m[/tex]

(b) 0.84 Hz

The frequency of oscillation of the system is given by

[tex]f=\frac{1}{2\pi}\sqrt{\frac{k}{m}}[/tex]

where

k = 80 N/m is the spring constant

m = 2.90 kg is the mass attached to the spring

Substituting the numbers into the formula, we find

[tex]f=\frac{1}{2\pi}\sqrt{\frac{80 N/m}{2.90 kg}}=0.84 Hz[/tex]

(c) 1.05 m/s

The maximum speed of a spring-mass system is given by

[tex]v=\omega A[/tex]

where

[tex]\omega[/tex] is the angular frequency

A is the amplitude of the motion

For this system, we have

[tex]\omega=2\pi f=2\pi (0.84 Hz)=5.25 rad/s[/tex]

[tex]A=0.200 m[/tex] (the amplitude corresponds to the maximum displacement, so it is equal to the initial displacement)

Substituting into the formula, we find the maximum speed:

[tex]v=(5.25 rad/s)(0.200 m)=1.05 m/s[/tex]

(d) x = 0

The maximum speed in a simple harmonic motion occurs at the equilibrium position. In fact, the total mechanical energy of the system is equal to the sum of the elastic potential energy (U) and the kinetic energy (K):

[tex]E=U+K=\frac{1}{2}kx^2+\frac{1}{2}mv^2[/tex]

where

k is the spring constant

x is the displacement

m is the mass

v is the speed

The mechanical energy E is constant: this means that when U increases, K decreases, and viceversa. Therefore, the maximum kinetic energy (and so the maximum speed) will occur when the elastic potential energy is minimum (zero), and this occurs when x=0.

(e) 5.51 m/s^2

In a simple harmonic motion, the maximum acceleration is given by

[tex]a=\omega^2 A[/tex]

Using the numbers we calculated in part c):

[tex]\omega=2\pi f=2\pi (0.84 Hz)=5.25 rad/s[/tex]

[tex]A=0.200 m[/tex]

we find immediately the maximum acceleration:

[tex]a=(5.25 rad/s)^2(0.200 m)=5.51 m/s^2[/tex]

(f) At the position of maximum displacement: [tex]x=\pm 0.200 m[/tex]

According to Newton's second law, the acceleration is directly proportional to the force on the mass:

[tex]a=\frac{F}{m}[/tex]

this means that the acceleration will be maximum when the force is maximum.

However, the force is given by Hooke's law:

[tex]F=kx[/tex]

so, the force is maximum when the displacement x is maximum: so, the maximum acceleration occurs at the position of maximum displacement.

(g) 1.60 J

The total mechanical energy of the system can be found by calculating the kinetic energy of the system at the equilibrium position, where x=0 and so the elastic potential energy U is zero. So we have

[tex]E=K=\frac{1}{2}mv_{max}^2[/tex]

where

m = 2.90 kg is the mass

[tex]v_{max}=1.05 m/s[/tex] is the maximum speed

Solving for E, we find

[tex]E=\frac{1}{2}(2.90 kg)(1.05 m/s)^2=1.60 J[/tex]

(h) 0.99 m/s

When the position is equal to 1/3 of the maximum displacement, we have

[tex]x=\frac{1}{3}(0.200 m)=0.0667 m[/tex]

so the elastic potential energy is

[tex]U=\frac{1}{2}kx^2=\frac{1}{2}(80 N/m)(0.0667 m)^2=0.18 J[/tex]

and since the total energy E = 1.60 J is conserved, the kinetic energy is

[tex]K=E-U=1.60 J-0.18 J=1.42 J[/tex]

And from the relationship between kinetic energy and speed, we can find the speed of the system:

[tex]v=\sqrt{\frac{2K}{m}}=\sqrt{\frac{2(1.42 J)}{2.90 kg}}=0.99 m/s[/tex]

(i) 1.84 m/s^2

When the position is equal to 1/3 of the maximum displacement, we have

[tex]x=\frac{1}{3}(0.200 m)=0.0667 m[/tex]

So the restoring force exerted by the spring on the mass is

[tex]F=kx=(80 N/m)(0.0667 m)=5.34 N[/tex]

And so, we can calculate the acceleration by using Newton's second law:

[tex]a=\frac{F}{m}=\frac{5.34 N}{2.90 kg}=1.84 m/s^2[/tex]

The spring constant of the dense object will be 80N/m.

The spring constant will be calculated thus:

k = f/m = 16/0.2 = 80N/m.

The frequency oscillation will be:

= 1/2π × ✓k/✓m

= 1/2π × ✓80/✓2.9

= 0.84 Hz

The maximum speed of the spring mass system will be:

v = [2π(0.84)] × 0.2

= 1.05m/s

The position on the x-axis where the maximum speed occur is at x = 0.

The maximum acceleration will be:

a = w²A

a = 5.25² × 0.2

= 5.51m/s²

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A) [tex]4.3\cdot 10^7 m/s[/tex]

For an electron moving in a region with both electric and magnetic field, the electron will move undeflected if the electric force on the electron is equal to the magnetic force:

[tex]qE= qvB[/tex]

which means that the speed of the electron will be

[tex]v=\frac{E}{B}[/tex]

where

E is the magnitude of the electric field

B is the magnitude of the magnetic field

In this problem,

[tex]B=2.5 mT=0.0025 T[/tex] is the intensity of the magnetic field

The electric field can be found as

[tex]E=\frac{V}{d}[/tex]

where

V = 600 V is the potential difference between the electrodes

[tex]d=5.6 mm=0.0056 m[/tex] is the distance between the electrodes

Substituting,

[tex]E=\frac{600 V}{0.0056 m}=1.07\cdot 10^5 V/m[/tex]

So the electron's speed is

[tex]v=\frac{1.07\cdot 10^5 V/m}{0.0025 T}=4.3\cdot 10^7 m/s[/tex]

B) [tex]9.8\cdot 10^{-2} m[/tex]

The radius of curvature of an electron in a magnetic field can be found by equalizing the centripetal force to the magnetic force:

[tex]m\frac{v^2}{r}=qvB[/tex]

where

m is the electron mass

v is the speed

r is the radius of curvature

q is the charge of the electron

Solving for r, we find

[tex]r=\frac{mv}{qB}=\frac{(9.11\cdot 10^{-31} kg)(4.3\cdot 10^7 m/s)}{(1.6\cdot 10^{-19} C)(0.0025 T)}=9.8\cdot 10^{-2} m[/tex]

Answer:

0.05 V/m

Explanation:

For a uniform electric field, electric field strength and potential difference are related by

[tex]E=\frac{\Delta V}{d}[/tex]

where

E is the electric field strength

[tex]\Delta V[/tex] is the potential difference

d is the distance between the two points

Here we have

[tex]\Delta V= 0.50 mV=5\cdot 10^{-4}V[/tex]

[tex]d=1.0 cm=0.01 m[/tex]

So, the electric field strength is

[tex]E=\frac{5\cdot 10^{-4} V}{0.01 m}=0.05 V/m[/tex]

Answer:

The correct answer is the third option: The kinetic energy of the water molecules decreases.

Explanation:

Temperature is, in depth, a statistical value; kind of an average of the particles movement in any physical system (such as a glass filled with water). Kinetic energy, for sure, is the energy resulting from movement (technically depending on mass and velocity of a system; in other words, the faster something moves, the greater its kinetic energy.

Since temperature is related to the total average random movement in a system, and so is the kinetic energy (related to movement through velocity), as the thermometer measures less temperature, that would mean that the particles (in this case: water particles) are moving slowly, so that: the slower something moves, the lower its kinetic energy.

In summary: temperature tells about how fast are moving and colliding the particles within a system, and since it is directly proportional to the amount of movement, it can be related (also directly proportional) to the kinectic energy.

The strength of the magnetic force on your head while driving west at the equator is 4.05 x 10^{-5} N, and the direction of this force is upwards, as determined by the right-hand rule.

The force on a charge moving in a magnetic field can be calculated using the formula F = qvB, where F is the force in newtons (N), q is the charge in coulombs (C), v is the velocity in meters per second (m/s), and B is the magnetic field strength in teslas (T). Given the charge on your head is 9 x 10^{-9} C, the Earth's magnetic field strength at the equator is 5 x 10^{-5} T, and your velocity driving west is 90 m/s, the magnitude of the magnetic force can be calculated as follows: F = 9  imes 10^{-9} C x 90 m/s x 5 x 10^{-5} T = 4.05 x 10^{-5} N.

Using the right-hand rule to determine the direction of the force: if you point your thumb in the direction of the velocity (west), and your fingers in the direction of the Earth's magnetic field (north), the force (perpendicular to the palm) will point upwards. Therefore, the direction of the magnetic force on your head is upwards.

Answer:

C. Farmers and gardeners should use other methods to provide crops with the nitrogen they need.

Explanation:

That was the right answer on study island :/

A. Lithium

The equation for the photoelectric effect is:

[tex]E=\phi + K[/tex]

where

[tex]E=\frac{hc}{\lambda}[/tex] is the energy of the incident light, with h being the Planck constant, c being the speed of light, and [tex]\lambda[/tex] being the wavelength

[tex]\phi[/tex] is the work function of the metal (the minimum energy needed to extract one photoelectron from the surface of the metal)

K is the maximum kinetic energy of the photoelectron

In this problem, we have

[tex]\lambda=190 nm=1.9\cdot 10^{-7}m[/tex], so the energy of the incident light is

[tex]E=\frac{hc}{\lambda}=\frac{(6.63\cdot 10^{-34}Js)(3\cdot 10^8 m/s)}{1.9\cdot 10^{-7} m}=1.05\cdot 10^{-18}J[/tex]

Converting in electronvolts,

[tex]E=\frac{1.05\cdot 10^{-18}J}{1.6\cdot 10^{-19} J/eV}=6.5 eV[/tex]

Since the electrons are emitted from the surface with a maximum kinetic energy of

K = 4.0 eV

The work function of this metal is

[tex]\phi = E-K=6.5 eV-4.0 eV=2.5 eV[/tex]

So, the metal is Lithium.

B. cesium, potassium, sodium

The wavelength of green light is

[tex]\lambda=510 nm=5.1\cdot 10^{-7} m[/tex]

So its energy is

[tex]E=\frac{hc}{\lambda}=\frac{(6.63\cdot 10^{-34}Js)(3\cdot 10^8 m/s)}{5.1\cdot 10^{-7} m}=3.9\cdot 10^{-19}J[/tex]

Converting in electronvolts,

[tex]E=\frac{3.9\cdot 10^{-19}J}{1.6\cdot 10^{-19} J/eV}=2.4 eV[/tex]

So, all the metals that have work function smaller than this value will be able to emit photoelectrons, so:

Cesium

Potassium

Sodium

C. 4.9 eV

In this case, we have

- Copper work function: [tex]\phi = 4.5 eV[/tex]

- Maximum kinetic energy of the emitted electrons: K = 2.7 eV

So, the energy of the incident light is

[tex]E=\phi+K=4.5 eV+2.7 eV=7.2 eV[/tex]

Then the copper is replaced with sodium, which has work function of

[tex]\phi = 2.3 eV[/tex]

So, if the same light shine on sodium, then the maximum kinetic energy of the emitted electrons will be

[tex]K=E-\phi = 7.2 eV-2.3 eV=4.9 eV[/tex]

The surface is most likely to be made of Lithium. Four metals (Cesium, Potassium, Sodium, and Lithium) will eject electrons when a green laser is shone on them. The maximum kinetic energy of the electrons emitted from Sodium will be approximately 4.9 eV.

Part A: Let's calculate the energy of the incident photon using Planck's equation E = h * c / λ , where h is Planck's constant (6.626 * 10^-34 J.s), c is the speed of light (3 * 10^8 m/s) and λ is the wavelength of the incident light (convert 190 nm to 1.9 * 10^-7 m). The energy of the photon (Ep) is approximately 6.6 eV. The given kinetic energy (Ek) of the most energetic electrons is 4.0 eV. According to the photoelectric effect, Ep = Work Function + Ek. So, the work function of the metal surface (Wf) is Ep - Ek, which gives us a work function of 2.6 eV. The closest value to this in the table is that of Lithium with 2.5 eV, so the surface is likely made of Lithium.

Part B: To find out the number of metals that will eject electrons when a green laser of wavelength 510 nm is shone on them, we first need to convert this wavelength into energy using the same formula as in Part A. The energy hence calculated is approximately 2.4 eV. As per the photoelectric effect, a metal can only eject electrons when its work function is less than or equal to the energy of the incident light. Therefore, only metals with work functions less than or equal to 2.4 eV will eject electrons. Looking at the table, we see that this covers Cesium, Potassium, Sodium, and Lithium. So, 4 metals will eject electrons.

Part C: Given the kinetic energy of electrons emitted from copper is 2.7 eV, and the work function of copper is 4.5 eV. According to the photoelectric effect, the energy of the incident radiation should be the sum of these two, which yields 7.2 eV. Now, if we replace the copper sample with sodium (having a work function of 2.3 eV), then the maximum kinetic energy of the emitted electrons from the sodium sample (Ek) will be the energy of the incident light minus the work function of Sodium i.e., 7.2 eV - 2.3 eV which is approximately 4.9 eV.

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Answer:

[tex]1.34\cdot 10^{-16} C[/tex]

Explanation:

The strength of the electric field produced by a charge Q is given by

[tex]E=k\frac{Q}{r^2}[/tex]

where

Q is the charge

r is the distance from the charge

k is the Coulomb's constant

In this problem, the electric field that can be detected by the fish is

[tex]E=3.00 \mu N/C = 3.00\cdot 10^{-6}N/C[/tex]

and the fish can detect the electric field at a distance of

[tex]r=63.5 cm = 0.635 m[/tex]

Substituting these numbers into the equation and solving for Q, we find the amount of charge needed:

[tex]Q=\frac{Er^2}{k}=\frac{(3.00\cdot 10^{-6} N/C)(0.635 m)^2}{9\cdot 10^9 Nm^2 C^{-2}}=1.34\cdot 10^{-16} C[/tex]

Final answer:

A point charge of approximately 1.35 × 10-13 coulombs would be required to produce an electric field change of 3.00 µN/C at a distance of 63.5 cm from the elephant nose fish.

Explanation:

To calculate the amount of charge needed to produce a change in the electric field of 3.00 µN/C at a distance of 63.5 cm, we can use Coulomb's law, which describes the electric field E created by a point charge Q. Coulomb's law is given by the equation E = kQ/r2, where k is Coulomb's constant (8.987 × 109 N m2/C2), Q is the charge in coulombs, and r is the distance from the charge in meters. To find Q, we rearrange the equation to Q = Er2/k.

By substituting the values, E = 3.00 µN/C (or 3.00 × 10-6 N/C), and the distance r = 63.5 cm (or 0.635 m), we can calculate the charge Q necessary to produce the observed electric field at the specified distance.

Calculation:

Q = (3.00 × 10-6 N/C) × (0.635 m)2 / (8.987 × 109 N m2/C2)

  = 1.35 × 10-13 C

So, a point charge of approximately 1.35 × 10-13 coulombs would be needed to produce an electric field change of 3.00 µN/C at a distance of 63.5 cm from the elephant nose fish.

Answer:

[tex]9.9\cdot 10^{-9}m[/tex]

Explanation:

In a single-slit diffraction pattern, the location of the first minimum is given by

[tex]y=\frac{L\lambda }{a}[/tex]

where

L is the distance between the slit and the screen

[tex]\lambda[/tex] is the wavelength

a is the width of the slit

In this problem, we have

[tex]y=0.527 cm = 5.27\cdot 10^{-3} m[/tex] (location of first minimum)

L = 1.068 m (distance of the screen)

[tex]a=2.00\mu m=2.00\cdot 10^{-6}m[/tex] (width of the slit)

Solving the equation for [tex]\lambda[/tex], we find the De Broglie wavelength of the electron:

[tex]\lambda = \frac{ya}{L}=\frac{(5.27\cdot 10^{-3} m)(2.00\cdot 10^{-6} m)}{1.068 m}=9.9\cdot 10^{-9}m[/tex]

The question examines the physics concept of diffraction about a beam of electrons passing through a narrow slit. De Broglie's hypothesis applies in this context as particles can exhibit characteristics of waves. The wavelength of the electron wave can be determined using the formula for the location of first-intensity minima, taking into consideration the values provided.

The question refers to a phenomenon known as diffraction, which is observed when electrons pass through a narrow slit toward a detector and create a diffraction pattern. The principle in question is the de Broglie hypothesis which maintains that particles can exhibit wave-like behavior. To calculate the wavelength λ of one of the electrons in this beam, we use the location of the first intensity minima formula: y=Lλ/a. In the given scenario, y is the distance from the center of the intensity minima to the broad maximum (0.527 cm), L is the distance to the screen (1.068 m), and a is the width of the slit (2.00μm). Using these values, you can solve for λ, the wavelength of the electron wave.

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Answer:

7 electrons

Explanation:

We can solve the problem by using the law of conservation of electric charge: in fact, the total electric charge before and after the collision must be conserved.

Before the collision, we have:

- A nucleus of carbon-12, consisting of 6 protons (charge +1 each) + 6 neutrons (charge 0 each), so total charge of +6

- A nucleus of nitrogen-14, consisting of 7 protons (charge +1 each) + 7 neutrons (charge 0 each), so total charge of +7

So the total charge before the collision is +6+7=+13 (1)

After the collision, we have:

- 17 protons (charge +1 each): total charge of +17

- 4 antiprotons (charge -1 each): total charge of -4

- 7 positrons (charge +1 each): total charge of +7

- 25 neutral particles (charge 0 each): total charge of 0

- N electrons (charge -1 each): total charge of -N

So the total charge after the collision is +17-4+7+0-N=+20-N (2)

Since the charge must be conserved, we have (1) = (2):

+13 = +20 - N

Solving for N,

N = 20 - 13 = 7

So, there are 7 electrons.

The number of electrons emitted in the collision between carbon-12 and nitrogen-14 nuclei detected as 17 protons, 4 antiprotons, 7 positrons, and 25 neutral particles, can be calculated to be 20 to maintain charge neutrality.

When the graduate student bombards nitrogen-14 nuclei with carbon-12 nuclei and detects the disintegration products including 17 protons, 4 antiprotons, 7 positrons, and 25 neutral particles, the amount of emitted electrons can be calculated by considering the charge balance of the particles. Since protons have a +1 charge and electrons have a -1 charge, positrons also have a +1 charge and antiprotons have a -1 charge, the net charge must remain the same as before the collision.

Originally, the nitrogen-14 nucleus (with 7 protons) and the carbon-12 nucleus (with 6 protons) totaled 13 positive charges. After the collision, the detected 17 protons and 7 positrons contribute +24 to the net charge, while 4 antiprotons contribute -4, making the total positive charge +20. To counterbalance this and maintain a neutral charge, 7 additional electrons (on top of the original 13) must have been emitted to bring the net charge back down to +13. Thus, in total, there must be 20 electrons emitted.

Answer:

[tex]-1.14 \cdot 10^{-3} V[/tex]

Explanation:

The induced emf in the loop is given by Faraday's Newmann Lenz law:

[tex]\epsilon = - \frac{d \Phi}{dt}[/tex] (1)

where

[tex]d\Phi[/tex] is the variation of magnetic flux

[tex]dt[/tex] is the variation of time

The magnetic flux through the coil is given by

[tex]\Phi = NBA cos \theta[/tex] (2)

where

N = 6 is the number of loops

A is the area of each loop

B is the magnetic field strength

[tex]\theta =15^{\circ}[/tex] is the angle between the direction of the magnetic field and the normal to the area of the coil

Since the radius of each loop is r = 5.00 cm = 0.05 m, the area is

[tex]A=\pi r^2 = \pi (0.05 m)^2=0.0079 m^2[/tex]

Substituting (2) into (1), we find

[tex]\epsilon = - \frac{d (NBA cos \theta)}{dt}= -(NAcos \theta) \frac{dB}{dt}[/tex]

where

[tex]\frac{dB}{dt}=0.0250 T/s[/tex] is the rate of variation of the magnetic field

Substituting numbers into the last formula, we find

[tex]\epsilon = -(6)(0.0079 m^2)(cos 15^{\circ})(0.0250 T/s)=-1.14 \cdot 10^{-3} V[/tex]

Answer:

Induced emf, [tex]\epsilon=-1.13\times 10^{-3}\ volts[/tex]

Explanation:

It is given that,

Number of circular loop, N = 6

A uniform magnetic field perpendicular to its surface is held stationary at an angle of 15 degrees to the ground.

Radius of the loop, r = 5 cm = 0.05 m

Change in magnetic field, [tex]\dfrac{dB}{dt}=0.025\ T/s[/tex]

Due to the change in magnetic field, an emf will be induced. Let E is the induced emf in the coil. it is given by :

[tex]\epsilon=\dfrac{d\phi}{dt}[/tex]

[tex]\phi[/tex] = magnetic flux

[tex]\epsilon=\dfrac{d(NBA\ cos\theta)}{dt}[/tex]

[tex]\epsilon=-NA\dfrac{d(B)}{dt}[/tex]

[tex]\epsilon=6\times \pi (0.05)^2\times 0.025\times cos(15)[/tex]

[tex]\epsilon=-1.13\times 10^{-3}\ volts[/tex]

So, the induced emf in the loop is [tex]1.13\times 10^{-3}\ volts[/tex] . Hence, this is the required solution.

(c) the fraction of energy lost during the impact

(a) [tex]7.32\cdot 10^7 Hz[/tex]

The frequency of an electromagnetic waves is given by:

[tex]f=\frac{c}{\lambda}[/tex]

where

[tex]c=3.0\cdot 10^8 m/s[/tex] is the speed of light

[tex]\lambda=4.1 m[/tex] is the wavelength of the wave in the problem

Substituting into the equation, we find

[tex]f=\frac{3.0\cdot 10^8 m/s}{4.1 m}=7.32\cdot 10^7 Hz[/tex]

(b) [tex]4.60\cdot 10^8 rad/s[/tex]

The angular frequency of a wave is given by

[tex]\omega = 2\pi f[/tex]

where

f is the frequency

For this wave,

[tex]f=7.32\cdot 10^7 Hz[/tex]

So the angular frequency is

[tex]\omega=2\pi(7.32\cdot 10^7 Hz)=4.60\cdot 10^8 rad/s[/tex]

(c) [tex]1.53 m^{-1}[/tex]

The angular wave number of a wave is given by

[tex]k=\frac{2\pi}{\lambda}[/tex]

where

[tex]\lambda[/tex] is the wavelength of the wave

For this wave, we have

[tex]\lambda=4.1 m[/tex]

so the angular wave number is

[tex]k=\frac{2\pi}{4.1 m}=1.53 m^{-1}[/tex]

(d) [tex]1.03\cdot 10^{-6}T[/tex]

For an electromagnetic wave,

[tex]E=cB[/tex]

where

E is the magnitude of the electric field component

c is the speed of light

B is the magnitude of the magnetic field component

For this wave,

E = 310 V/m

So we can re-arrange the equation to find B:

[tex]B=\frac{E}{c}=\frac{310 V/m}{3\cdot 10^8 m/s}=1.03\cdot 10^{-6}T[/tex]

(e) z-axis

In an electromagnetic wave, the electric field and the magnetic field oscillate perpendicular to each other, and they both oscillate perpendicular to the direction of propagation of the wave. Therefore, we have:

- direction of propagation of the wave --> positive x axis

- direction of oscillation of electric field --> y axis

- direction of oscillation of magnetic field --> perpendicular to both, so it must be z-axis

(f) 127.5 W/m^2

The time-averaged rate of energy flow of an electromagnetic wave is given by:

[tex]I=\frac{E^2}{2\mu_0 c}[/tex]

where we have

E = 310 V/m is the amplitude of the electric field

[tex]\mu_0[/tex] is the vacuum permeability

c is the speed of light

Substituting into the formula,

[tex]I=\frac{(310 V/m)^2}{2(4\pi\cdot 10^{-7} H/m) (3\cdot 10^8 m/s)}=127.5 W/m^2[/tex]

(g) [tex]1.53\cdot 10^{-8} kg m/s[/tex]

For a surface that totally absorbs the wave, the rate at which momentum is transferred to the surface given by

[tex]\frac{dp}{dt}=\frac{<S>A}{c}[/tex]

where the <S> is the magnitude of the Poynting vector, given by

[tex]<S>=\frac{EB}{\mu_0}=\frac{(310 V/m)(1.03\cdot 10^{-6} T)}{4\pi \cdot 10^{-7}H/m}=254.2 W/m^2[/tex]

and where the surface is

A = 1.8 m^2

Substituting, we find

[tex]\frac{dp}{dt}=\frac{(254.2 W/m^2)(1.8 m^2)}{3\cdot 10^8 m/s}=1.53\cdot 10^{-8} kg m/s[/tex]

(h) [tex]8.47\cdot 10^{-7} N/m^2[/tex]

For a surface that totally absorbs the wave, the radiation pressure is given by

[tex]p=\frac{<S>}{c}[/tex]

where we have

[tex]<S>=254.2 W/m^2[/tex]

[tex]c=3\cdot 10^8 m/s[/tex]

Substituting, we find

[tex]p=\frac{254.2 W/m^2}{3\cdot 10^8 m/s}=8.47\cdot 10^{-7} N/m^2[/tex]

(a) 3.33

For a capacitor with dielectric disconnected from the battery, the relationship between the voltage across the capacitor without the dielectric (V) and with the dielectric (V) is given by

[tex]V' = \frac{V}{k}[/tex]

where

k is the dielectric constant of the material

In this problem, we have

[tex]V' = 3.6 V[/tex]

[tex]V=12 V[/tex]

So we can re-arrange the formula to find the dielectric constant:

[tex]k=\frac{V}{V'}=\frac{12 V}{3.6 V}=3.33[/tex]

(b) The energy stored reduces by a factor 3.33

The energy stored in a capacitor is

[tex]U=\frac{1}{2}QV[/tex]

where

Q is the charge stored on the capacitor

V is the voltage across the capacitor

Here we can write the initial energy stored in the capacitor (without dielectric) as

[tex]U=\frac{1}{2}QV[/tex]

while after inserting the dielectric is

[tex]U'=\frac{1}{2}QV' = \frac{1}{2}Q\frac{V}{k}[/tex]

since Q, the charge, has not changed (the capacitor is disconnected, so the charge cannot flow away from the capacitor).

So the ratio between the two energies is

[tex]\frac{U'}{U}=\frac{\frac{1}{2}Q\frac{V}{k}}{\frac{1}{2}QV}=\frac{1}{k}[/tex]

which means

[tex]U' = \frac{U}{k}=\frac{U}{3.33}[/tex]

So, the energy stored has decreased by a factor 3.33.

(c) 5.5 V

Pulling the dielectric only partway so that it fills half of the space between the plates is equivalent to a system of 2 capacitors in parallel, each of them with area A/2 (where A is the original area of the plates of the capacitor), of which one of the two is filled with dielectric while the other one is not.

Calling

[tex]C=\frac{\epsilon_0 A}{d}[/tex] the initial capacitance of the capacitor without dielectric

The capacitance of the part of the capacitor of area A/2 without dielectric is

[tex]C_1 = \frac{\epsilon_0 \frac{A}{2}}{d}= \frac{C}{2}[/tex]

while the capacitance of the part of the capacitor with dielectric is

[tex]C_2 = \frac{k \epsilon_0 \frac{A}{2}}{d}= \frac{kC}{2}[/tex]

The two are in parallel, so their total capacitance is

[tex]C' = C_1 + C_2 = \frac{C}{2}+\frac{kC}{2}=(1+k)\frac{C}{2}=(1+3.33)\frac{C}{2}=2.17 C[/tex]

We also have that

[tex]V=\frac{Q}{C}=12 V[/tex] this is the initial voltage

So the final voltage will be

[tex]V' = \frac{Q}{C'}=\frac{Q}{2.17 C}=\frac{1}{2.17}V=\frac{12 V}{2.17}=5.5 V[/tex]

Final answer:

The dielectric constant of the material is 3.3 based on the voltage drop after insertion between the capacitor's plates from 12 V to 3.6 V. The insertion of the dielectric changes the stored energy to 9% of the original. With half the space filled by the dielectric, the voltmeter would read approximately 5.6 V.

Explanation:

The question concerns the concept of capacitors in physics, specifically the effects of inserting a dielectric material between the plates of a parallel-plate capacitor. Assuming that the battery has been disconnected and there is no charge loss during the process, let's address the parts of the question step by step.

(a) Dielectric constant of the material

The dielectric constant (K) of a material can be determined by the ratio of the initial voltage (Vo) to the voltage (V) after the dielectric has been inserted. Given that the initial voltage is 12 V and it drops to 3.6 V, the dielectric constant is K = Vo / V = 12 / 3.6 = 3.3. Therefore, the dielectric constant of this material is 3.3.

(b) Fraction of the stored energy changed

The stored energy in a capacitor is proportional to the square of the voltage across it. When the voltage drops due to the insertion of the dielectric, the energy stored changes by a factor of (V / Vo)2. Hence, the fraction of the energy change is (3.6 / 12)2 = 0.09, or 9% of the original stored energy.

(c) Voltmeter reading with half space filled by the dielectric

When the dielectric only fills half of the space between the plates, the effective dielectric constant becomes a weighted average of the dielectric and air (K=1). Assuming the dielectric constant of the inserted material is 3.3, and it fills half the space, the effective dielectric constant is (3.3 + 1) / 2 = 2.15. Thus, the new voltage is Vnew = Vo / Keff = 12 / 2.15 = 5.58 V. Therefore, the voltmeter will read approximately 5.6 V when the dielectric fills only half of the space between the plates.

17.

There are three different methods for charging objects:

- Friction: in friction, two objects are rubbed against each other. As a result, electrons can be passed from one object to the other, so one object will gain a net negative charge while the other object will gain a net positive charge due to the lack of electrons.

- Conduction: this occurs when two conductive objects are put in contact with each other, and charges (electrons, usually) are transferred from one object to the other one.

- Induction: this occurs when two objects are brought closer to each other, but not in contact. If one of the two objects has a net charge (different from zero) on its surface, then it will induce a movement of charges in the second object: in particular, in the second object, charges of the opposite polarity will be attracted towards the first object, while charges of same polarity will be repelled further away.

18.

Charged objects produce around themselves an electric field. The strenght of the electric field is given by (assuming the charged objects are spherical)

[tex]E=k\frac{q}{r^2}[/tex]

where k is the Coulomb's constant, q is the magnitude of the charge and r the distance from the centre of the charge. As we see, the strength of the field is inversely proportional to the square of the distance.

Also, the direction of the field is determined by the sign of the charge:

- if the charge is positive, the electric field points away from the charge (this means that other positive charges in the field will be repelled away)

- if the charge is negative, the electric field points towards the charge (this means that other positive charges in the field will be attracted towards it)

19.

Electrical force is given by:

[tex]F=k\frac{q_1 q_2}{r^2}[/tex]

where k is the Coulomb's constant, q1 and q2 are the two charges, and r their separation.

Gravitational force is given by:

[tex]F=G\frac{m_1 m_2}{r^2}[/tex]

where G is the gravitational constant, m1 and m2 are the masses of the two objects, and r their separation.

Similarities between the two forces:

- Both are inversely proportional to the square of the distance between the two objects, r

- Both are non-contact forces (the two objects can experience the forces even if they are not in contact)

- Both forces have infinite range

Differencies between the two forces:

- The electric force can be either attractive or repulsive, while the gravitational force is attractive only

- The electric force is much stronger than the gravitational force, due to the much larger value of the Coulomb's constant k compared to the gravitational constant G