Why do you see lightning before you hear thunder

Answer:

Line 3 has a mistake.

Explanation:

Electromagnetic waves consist of oscillations of electric and magnetic fields that oscillate perpendicular to the each other. Therefore, Line 1 is correct.

Also, the fields in an electromagnetic waves oscillate perpendicular to the direction of propagation of the wave: therefore, they are transverse waves. So Line 2 is also correct.

Electromagnetic waves, contrary to mechanical waves, do not need a medium to propagate: so, they can also travel through a vacuum. Therefore, Line 3 is wrong.

Finally, all electromagnetic waves travel through a vacuum at the same speed, called speed of light:

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

So, Line 4 is also correct.

Answer:

Line 3 is the mistake

Explanation:

Line 3 is incorrect because electromagnetic waves can travel with or without a medium, meaning they CAN travel through space.

Answer:

When a candle burns, the chemical energy in the candle changes to light energy and heat energy. (C)

Explanation:

Did you ever light a candle and have sound or electricity come out of it ? ?

Answer:

C. light and heat

Explanation:

When the candle is burnt, the chemical energy is converted to light and heat.

Light is easily visible. Heat is dependent on the size of the candle. If a small candle is burnt heat will not be much and can only be felt if one is very close to its flame.

Sound waves and electrical energies are not created while a candle burns.

Explanation:

There are three ways in which heat is transmitted:  

1. By Conduction, when the transmission is by the direct contact.  

2. By Convection, heat transfer in fluids (like water or the air, for example).  

3. By Radiation, by the electromagnetic waves (they can travel through any medium and in vacumm).

So, the space between the Earth and the Sun is vacuum, this means the energy cannot be transmitted by convection, nor conduction. It must be transmitted by electromagnetic waves that are able to travel with or without a medium, and this is called radiation.

Answer:

B. Multi-cell line

Explanation:

A multi-cell line, or how it is more commonly known, a squall line, is basically a group of storms forming a line, like a bow, they have been seen to cover  hundreds of miles long but usually only 10 or 20 miles wide.

It is theorized that this is because when a cyclone is formed, there are two forces of "wind" one ahead and one behind, concentrating air masses as if the winds were "squishing" them to form a line.

Answer: Multi-cell Line

Explanation:

Multi-cell line storms form in a long, narrow line. While multi-cell lines may be just 10 to 20 miles wide, they can be hundreds of miles long. Multi-cell lines are known as "squall lines."

Answer:

object moves up

Explanation:

Answer:

The object F moves up

Explanation:

Answer:

C. At twice the distance, the magnitude of the field is B/2

Explanation:

The strength of the magnetic field produced by a current-carrying wire is:

[tex]B=\frac{\mu_0 I}{2\pi r}[/tex]

where

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

I is the current

r is the distance from the wire

If we double the distance,

r' = 2r

so the new magnetic field strength will be

[tex]B'=\frac{\mu_0 I}{2\pi (2r)}= \frac{1}{2}(\frac{\mu_0 I}{2\pi r})=\frac{B}{2}[/tex]

So, the correct option is

C. At twice the distance, the magnitude of the field is B/2

At twice the distance, the magnitude of the magnetic field is B/2 due to increase in the distance between them.

Strength of magnetic field is inversely proportional to the distance of a conductor. If the distance of an object is decrease, its magnetic field increase while on the other hand, if the distance is decrease the intensity of magnetic field on that object or charge increases.

The strength of the magnetic field at its peak near to the source but moving away from it gradually decreases the strength of the magnetic field so we can conclude that double the distance, the magnitude of magnetic field become half.

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Answer:

84.6 J

Explanation:

The work done by the force is given by

[tex]W=Fd cos \theta[/tex]

where

W is the work done

F = 15 N is the force applied

d = 6.0 m is the displacement

[tex]\theta=20^{\circ}[/tex] is the angle between the force's direction and the displacement

Substituting the numbers into the equation, we find

[tex]W=(15 N)(6.0 m)cos 20^{\circ} =84.6 J[/tex]

A 5.0 kg object is pulled by a 15-N force acting 20 °C above the horizontal. After moving for 6.0 m, the work done is 85 J.

In physics, work is the energy transferred to or from an object via the application of force along a displacement.

A 5.0 kg object is pulled by a 15-N force acting 20 ° above the horizontal. We can calculate the work done after the object moved 6.0 m using the following expression.

W = F × s × cosθ

W = 15 N × 6.0 m × cos 20° = 85 J

where,

A 5.0 kg object is pulled by a 15-N force acting 20 °C above the horizontal. After moving for 6.0 m, the work done is 85 J.

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Explanation:

Given:

Va = 36 km/s = 3.6×10⁴ m/s

Vb = 12 km/s = 1.2×10⁴ m/s

T = 137 d = 1.18×10⁷ s

For each star, circumference = velocity * time:

2π R = V T

R = V T / (2π)

So Ra = Va T / (2π), and Rb = Vb T / (2π).

Sum of the forces on Alpha:

Ma Va² / Ra = G Ma Mb / (Ra + Rb)²

Va² / Ra = G Mb / (Ra + Rb)²

Mb = Va² (Ra + Rb)² / (G Ra)

Similarly, sum of the forces on Beta:

Mb Vb² / Rb = G Ma Mb / (Ra + Rb)²

Vb² / Rb = G Ma / (Ra + Rb)²

Ma = Vb² (Ra + Rb)² / (G Rb)

First, calculate Ra and Rb:

Ra = (3.6×10⁴) (1.18×10⁷) / (2π)

Ra = 6.78×10¹⁰

Rb = (1.2×10⁴) (1.18×10⁷) / (2π)

Rb = 2.26×10¹⁰

Therefore, the mass of Alpha is:

Ma = (1.2×10⁴)² (6.78×10¹⁰ + 2.26×10¹⁰)² / (6.67×10⁻¹¹ × 2.26×10¹⁰)

Ma = 7.81×10²⁹ kg

And the mass of Beta is:

Mb = (3.6×10⁴)² (6.78×10¹⁰ + 2.26×10¹⁰)² / (6.67×10⁻¹¹ × 6.78×10¹⁰)

Mb = 2.34×10³⁰ kg

Answer is :

Mercury ( Hg)

Answer:

I think it's Mercury also known as Quicksilver

Explanation:

Prior to the knowledge of this element's toxicity, Mercury was commonly used in thermometers. It is a metal that exists in a liquid state at room temp.

Answer:

I believe the answere is B)

Explanation:

Well, as the light enters the atmosphere it meets resestance.And since the atmosphere is essentially a thick layer of chemicals in the form of gasses under pressure it isn't very smooth.So as a result, the light mainly scatters towards different dirrections.I am happy to help.Contact me if you have any further questions.

Yours sincerely,

Manos.

Answer:

C. Sink until it reaches equilibrium and then remain at a constant depth.

Explanation:

An object immersed in a fluid experiences buoyant force. If the net buoyant force is greater than the net weigh of the object, the object will float.

If the net buoyant force is less than the net wight of the object, it will sink until a depth where the total weight of the object and the force due to the fluid above the object equals the net buoyant force at the bottom of the object (equilibrium), then the object remains at a constant depth.

A weighted, air-filled balloon that sinks in a lake will continue to sink until the buoyant force equals its weight, at which point it reaches equilibrium and remains at a constant depth.

If a weighted, air-filled balloon sinks in a lake, it will sink until it reaches equilibrium and then remain at a constant depth. This happens because the buoyant force always acts upward on any object submerged in a fluid. However, if this force is less than the object's weight, the object will sink. The object reaches a point of equilibrium when the buoyant force equals the object's weight, causing it to stop sinking and remain suspended at a particular depth. Objects that sink, such as submarines with adjustable density (ballast tanks), demonstrate instances where they can be made to sink or float as desired, depending on the relationship between the buoyant force and the object's weight.

Explanation:

The portion visible by the human eye of the electromagnetic spectrum is between 380 nm (violet-blue) and 780 nm (red) approximately.  Which  means this part of the spectrum is located between ultraviolet light and infrared light.  

Note the fact only part of the whole electromagnetic spectrum is visible to humans is because the receptors in our eyes are only sensitive to these wavelengths.

Therefore:

Answer: It would the age of the star.

Explanation:

Answer:

The image distance is 13.3 cm  ⇒ answer B

Explanation:

* Lets study the information in the problem

- The distance between the object and the convex lens is 40.0 cm

- The lens focuses light at a distance of 10.0 cm

- The equation of the image distance is [tex]d_{i}=\frac{d_{o}f}{d_{o}-f}[/tex]

 where di is the image distance, do is the object distance and f is the

 distance of the focuses lens

* Lets solve the problem

∵ do = 40.0 cm

∵ f = 10.0 cm

∵ [tex]d_{i}=\frac{d_{0}f}{d_{o}-f}[/tex]

- Substitute the values of do and f in the equation

∴ [tex]d_{i}=\frac{(40.0)(10.0)}{(40.0)-(10.0)}=\frac{400.0}{30.0}=\frac{40}{3}[/tex]

∴ di = 13.3333 ≅ 13.3 cm

* The image distance is 13.3 cm

Answer: Exist naturally

Explanation: Hope This Helps ..!

The solid, inorganic portion of the earth system is known as the Lithosphere.

The lithosphere is the portion of the earth composed of rocks, minerals, and elements. also, the lithosphere is considered as the interior and the exterior of the solid earth.

The lithosphere is made up of three main types of rocks:

This type of rock is formed by the solidification of molten rocks.

This type of rock is formed by the adulteration of alteration and compression of old rock debris or organic sediments.

The alteration of existing rocks by intense heat or pressure causes the formation of Metamorphic rock.

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Ok so we know that electric power is:

[tex]P=UI=I^2R[/tex]

If we express resistance.

[tex]R=\dfrac{P}{I^2}[/tex]

Now if you have 100W of power you will probably get a bigger resistance than with 40W of power.

However here it says that the resistance of 40W bulb is bigger than 100W bulb. Which means the statement is incorrect.

Hope this helps.

r3t40

Answer:

Zero Newtons

Explanation:

Newton's second law of motion states that the net force applied to an object is equal to the product between the object's mass and its acceleration:

[tex]F=ma[/tex]

In this case, we want the hockey puck to slide at constant velocity - constant velocity means zero acceleration:

a = 0

And so this means also that the net force is zero:

F = 0

However, the problem says that ice friction and air resistance are negligible - so there are no forces acting on the hockey puck. This means that the puck will continue its motion at constant velocity if we don't apply any other force on it.

Final answer:

Zero newtons. option D

Explanation:

The question pertains to the concept of Newton's first law of motion, which states that an object in motion will remain in motion with a constant velocity, and an object at rest will remain at rest, unless acted upon by a net external force.

In the scenario where a hockey puck is set in motion across a frictionless surface such as a frozen pond, and where air friction is also neglected, the force required to keep the puck sliding at constant velocity is zero newtons.

This is because once the puck is in motion, no additional force is needed to maintain its state of motion. In reality, ice isn't perfectly frictionless and air resistance is usually present, causing the puck to eventually slow down.

However, in the theoretical scenario presented, with no force opposing the puck's motion, no additional force is required to maintain its constant velocity, according to Newton's first law of motion.

Answer:

False

Explanation:

The inner planets are called terrestrial planets due to the surfaces are solid (similar to Earth)-made up of heavy metals, either have no moons or few moons.

The outer planets are called Jovian planets or gas giants because they are encased in gas.  They all have rings with plenty of moons.

The statement "The outer planets are similar to the planet Earth; they just happen to be farther away from the Sun." is False.

Therefore, the outer planets are not similar to the Earth, so the statement is false.

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The half-life of an isotope of cesium is several thousand years, meaning that it will take a very long time for the mass to halve. However, it may be another 20 thousand years before Chernobyl will be inhabitable again.

Answer:

D Any of the above depending on the directions of forces.

Explanation:

The net force on the box depends on the direction of the forces.

For example, we have three special cases:

- If the two forces are in the same direction, they add to each other, so the net force is

F = 10 N + 10 N = 20 N

- If the two forces are in opposite directions, the net force is given by the difference between the two forces, so

F = 10 N - 10 N = 0 N

- If the two forces are perpendicular to each other, their resultant is given by the Pythagorean theorem:

[tex]F=\sqrt{(10 N)^2 + (10 N)^2}=14.1 N[/tex]

If the two forces are at any other angle, their resultant can be found by resolving each force along the x- and y- direction, and adding the components along each direction. The resultant net force will have a magnitude between 0 N and 20 N.

Final answer:

The net force on a box when two 10-N forces are applied depends on the directions of the forces: they could sum to 20 N, result in about 14 N due to perpendicular directions, or cancel out to zero if they are opposite.

Explanation:

When considering the net force acting on an object, such as a box of candy, it is critical to take into account the directions of the forces applied to the object. The net force is a vector quantity, which means it has both magnitude and direction. Therefore, the resultant force depends on how the individual forces are directed relative to one another.

If the pair of 10-N forces act in the same direction, they would add together to give a net force of 20 N in that direction. If the forces were to act at right angles to each other, they would combine to produce a net force of approximately 14 N (calculated using the Pythagorean theorem). However, if the two forces were directed opposite to each other, they would cancel each other out, resulting in a net force of zero.

Thus, the correct answer to the question is 'D Any of the above depending on the directions of forces.'

Answer: The magnetic lines of force enter the Earth through the South magnetic Pole.

Let's start by explaining that Earth is similar to a magnetic bar with a north pole and a south pole. This means, the axis that crosses the Earth from pole to pole is like a big magnet.

Now, by convention, on all magnets the north pole is where the magnetic lines of force leave the magnet and the south pole is where the magnetic lines of force enter the magnet.

Then, for the case of the Earth, the north pole of the magnet is located towards the geographic south pole and the south pole of the magnet is near the geographic north pole.

That is why the north pole of the needle of a compass (being a north magnetic pole) is attracted by the geographic north pole (which is a magnetic south pole), as the opposite poles are attracted.

And it is for this reason, moreover, that the magnetic field lines enter the Earth through its magnetic south pole (which is the geographic north pole).

Magnetic lines of force enter Earth at the magnetic poles. The magnetic poles are located near the geographic poles, but they are not exactly the same.

The North Magnetic Pole is currently located in northern Canada, and the South Magnetic Pole is currently located in Antarctica.

Magnetic lines of force are invisible, but they can be represented by lines that show the direction of the magnetic field. The lines of force enter Earth at the magnetic poles and exit at the opposite poles. They are strongest at the poles and weakest at the equator.

The Earth's magnetic field is generated by the movement of liquid iron in the Earth's core. The liquid iron is constantly moving, and this movement creates an electric current. The electric current, in turn, creates the magnetic field.

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λ = 2 m.

The easiest way to solve this problem is using the equation of frecuency of a wave f = v/λ, where v is the velocity of the wave, and λ is the wavelength.

To calculate the wavelength of a microwave light travels through a liquid, it moves at a speed of 2.2 x 10⁸ m/s. If the frecuency of the light wave is 1.1 x 10⁸ Hz, we have to clear λ from the equation f = v/λ:

f = v/λ -------> λ = v/f

λ = 2.2 x 10⁸ m/s / 1.1 x 10⁸ Hz

λ = 2 m (wavelength of the microwave)

Julius Robert Mayer discovered the Law of Conservation of Energy.

Answer:

Julius Robert Mayer in 1842

Explanation:

According to the law of reflection, when a ray of light strikes a surface, the angle of this ray (incident ray) with respect to the normal of the surface is equal to the angle that forms the reflected ray with the same normal of the surface.

In other words:

Both the incident ray and the reflected ray and the normal to the surface are in the same plane, in addition, the angle of the incident ray is equal to the angle of the reflected ray.

In this context, when a ray strikes the surface perpendicular to it, both the incident angle and the reflected angle will be zero, since the normal to the surface is also perpendicular to it.

The atomic nuclei of almost all elements consist of protons and neutrons.

The nucleus of an atom has very small dimensions. However, it occupies its central part and concentrates more than 99% of its total mass.

It is in the nucleus that the protons (positive charge) and neutrons (neutral charge) are found.

Answer: [tex]1.212(10)^{-10} m[/tex]

Explanation:

The de Broglie wavelength [tex]\lambda[/tex] is given by the following formula:

[tex]\lambda=\frac{h}{p}[/tex] (1)

Where:

[tex]h=6.626(10)^{-34}\frac{m^{2}kg}{s}[/tex] is the Planck constant

[tex]p[/tex] is the momentum of the atom, which is given by:

[tex]p=m_{e}v[/tex] (2)

Where:

[tex]m_{e}=9.11(10)^{-28}g=9.11(10)^{-31}kg[/tex] is the mass of the electron

[tex]v=6(10)^{6}m/s[/tex] is the velocity of the electron

This means equation (2) can be written as:

[tex]p=(9.11(10)^{-31}kg)(6(10)^{6}m/s)[/tex] (3)

Substituting (3) in (1):

[tex]\lambda=\frac{6.626(10)^{-34}\frac{m^{2}kg}{s}}{(9.11(10)^{-31}kg)(6(10)^{6}m/s)}[/tex] (4)

Now, we only have to find [tex]\lambda[/tex]:

[tex]\lambda=1.2122(10)^{-10} m[/tex]>>> This is the de Broglie wavelength of the electron

Final answer:

Using the de Broglie equation, the de Broglie wavelength of an electron with a velocity of 6.00 × 106 m/s is calculated to be approximately 1.21 × 10-10 meters.

Explanation:

The de Broglie wavelength of an electron can be calculated using the de Broglie equation λ = h / (mv), where λ is the wavelength, h is Planck's constant (6.626 × 10-34 m2kg/s), m is the mass of the electron, and v is the velocity of the electron. The mass of an electron given is 9.11 × 10-28 g, which first needs to be converted to kilograms (kg) by dividing by 1000 to give 9.11 × 10-31 kg. Plugging the values into the equation: λ = 6.626 × 10-34 m2kg/s / (9.11 × 10-31 kg × 6.00 × 106 m/s), we can calculate the de Broglie wavelength to be approximately 1.21 × 10-10 meters, or 0.121 nanometers.

An interactive animation of a black hole would best enhance a reader's understanding due to its dynamic representation of gravitational effects.

The student is seeking to understand which features would enhance the reader’s understanding of a passage about black holes. In Neil deGrasse Tyson’s description, black holes are characterized by their intense gravitational pull that even light cannot escape. Given the complexity of the concept, an interactive animation of a black hole is arguably the most effective tool for understanding, as it would visually demonstrate how gravity affects space-time and objects around a black hole. A photograph provides a static image lacking explanatory power. On the other hand, while a demonstration of the speed of light informatively highlights a physical constant, it does not directly illustrate why light cannot escape. A definition of a black hole, while foundational, does not provide the dynamic understanding that an animation would.

Answer:

its c

Explanation:

trust ur homeboy

7.5 x 10⁻¹¹m. An electromagnetic wave of frecuency 4.0 x 10¹⁸Hz has a wavelength of 7.5 x 10⁻¹¹m.

Wavelength is the distance traveled by a periodic disturbance that propagates through a medium in a certain time interval. The wavelength, also known as the space period, is the inverse of the frequency. The wavelength is usually represented by the Greek letter λ.

λ = v/f. Where v is the speed of propagation of the wave, and "f" is the frequency.

An electromagnetic wave has a frecuency of 4.0 x 10 ¹⁸Hz and the speed of light is 3.0 x 10⁸ m/s. So:

λ = (3.0 x 10⁸ m/s)/(4.0 x 10¹⁸ Hz)

λ = 7.5 x 10⁻¹¹m