Which of the following accurately describes properties of valence? A. The greater the number of electrons an atom has to borrow or to lend, the greater the activity of the atom. B. Metals tend to have a negative valence and tend to be electron borrowers. C. The smaller the number of electrons an atom has to borrow or to lend, the greater the activity of the atom. D. Nonmetallic elements tend to have a positive valence and tend to be electron borrowers.

Answer: The answer is C. 4.9 sec.

Explanation:

Answer:

c) 4.9 s

Explanation:

Young's modulus of aluminium is given as

[tex]Y = 69 \times 10^9 pa[/tex]

density of aluminium is given as

[tex]\rho = 2700 kg/m^3[/tex]

now the speed of sound in aluminium is given as

[tex]v = \sqrt{\frac{Y}{\rho}}[/tex]

[tex]v = \sqrt{\frac{69 \times 10^9}{2700}}[/tex]

[tex]v = 5055.3 m/s[/tex]

now the time taken by the sound to travel a distance of d = 25 km

[tex]t = \frac{d}{v}[/tex]

[tex]t = \frac{25 \times 10^3}{5055.3}[/tex]

[tex]t = 4.9 s[/tex]

If the voltage impressed across the ends of the circuit were doubled then its new current would be 120 milliAmps

Ohm's law claims that the voltage across a conductor is directly proportional to the current flowing through it.

This current-voltage connection may be expressed mathematically as,

The Equation of Ohm's Law is given as;

[tex]\rm V=IR \\\\ I=\frac{V}{R} \\\\[/tex]

If the resistance is constant. The current is directly propotional to the voltage;

If the voltage value is doubled the value of the current in the circuit ios is also doubled. The value of the new current will be;

[tex]\rm I' = 60 \times 2 \\\\ \rm I' = 120 \ mA[/tex]

Hence if the voltage impressed across the ends of the circuit were doubled then its new current would be 120 milliAmps

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Final answer:

According to Ohm's Law, if the voltage in a circuit is doubled while the resistance remains constant, the current would also double. Therefore, if the initial current is 60.0 milliAmps and the voltage doubles, the new current would be 120.0 milliAmps.

Explanation:

The question deals with Ohm's Law, which is a fundamental principle in physics that describes the relationship between voltage, current, and resistance in an electrical circuit. According to Ohm's Law, the current in a circuit is directly proportional to the voltage across it and inversely proportional to the resistance of the circuit. Thus, if the voltage in a circuit is doubled while the resistance remains constant, the current would also double.

Given that the initial current in the wires of a circuit is 60.0 milliAmps, and if the voltage impressed across the ends of the circuit were doubled without any change in its resistance, the new current would be 120.0 milliAmps.

Answer:

the Hudson Bay was covered with alpine glaciers

Explanation:

During the last glacial period, large portions of North America were covered with ice. The majority of the ice was from the ice sheets that were covering Canada and the northern part of the United States, and the alpine glaciers on the mountain ranges. Hudson Bay was all frozen at this point of time. It was not covered with alpine glaciers though, instead it was covered with the ice of the extended ice sheets, with the ice cover reaching up to 2 km in thickness.

Answer:

Blue-green bacteria or cynobacteria belong to the kingdom Monera

Blue-green bacteria belongs to the kingdom

a. Monera.

The electron is the subatomic particle that determines an element's reactivity, with the configuration of the outermost or valence shell playing a key role in how readily an element undergoes chemical reactions.

The subatomic particle responsible for determining the reactivity of an element is the electron. The electrons in the outermost subshell, or valence shell, have the most significant interaction with other atoms, as they are farthest from the nucleus. An element is chemically reactive if its valence shell can easily accept or give up electrons. For instance, noble gases like helium and neon have a full valence shell and are very stable—they do not react easily due to their high ionization energies and unwillingness to accept an additional electron. On the other hand, elements like hydrogen have an incomplete valence shell, making them more reactive as they seek stability through reactions with other elements.

Answer:

Read below!

Explanation:

You can watch the sun wheel across the sky during the day, and the stars at night. Focus a telescope on any star besides the north star--especially southern stars--and you can watch them drift across your field of view.  

An alternative explanation is that all the stars are painted on (or holes in) some canopy that rotates around the earth. This explanation does not account for the motion of the "wanderers," or planets, as the Greeks called them, or for the path of the moon among the stars.  

As we know the stars are massive bodies of significant and varying distance to the earth, the notion they all swing around us in unison seems highly implausible

The answer is: B a meteorite

The answer is B which is a meteorite.

Answer:

539 kPa

Explanation:

Pressure equals density times acceleration of gravity times depth.

P = ρgh

Water has a density of 1000 kg/m³, and acceleration of gravity is 9.8 m/s².

P = (1000 kg/m³) (9.8 m/s²) (55.0 m)

P = 539,000 Pa

P = 539 kPa

Answer:

Because the gravitational attraction of the Sun hold them in motion around it

Explanation:

For an object travelling in a straight path at constant velocity, the net force acting on the object must be zero.

The planets in the Solar System, however, do not experience a zero net force: in fact, the Sun exerts a gravitational attraction on them, whose magnitude is given by

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

where

G is the gravitational constant

M is the mass of the Sun

m is the mass of the planet

r is the average distance between the Sun and the planet

Due to the presence of this force, the Sun makes the planets 'deviating' from their straight path, forcing them to following an elliptical path around the Sun.

Answer:

The total charge that passes through the player in 900s is Δq = 108C

Explanation:

Charge and current

The concept of electric charge is the fundamental principle to explain all electrical phenomena. Also, the basic quantity in an electrical circuit is the electric charge. All people experience the effect of electric charge when they try to take off a wool sweater and it is stuck to the body or when they go through a carpet and receive an electric shock.

Charge is an electrical property of the atomic particles of which matter is composed, measured in coulombs (C).

Electric current is the rate of change of the load with respect to time,  measure in amperes (A).

Mathematically, the relationship between current i, charge q and time t is:

i = dq/dt

Δq = i Δt

Δq = 0.120A x 900s = 108C

Answer:

Electric charge

Like; opposite

Faster

True

True

positive to negative

Explanation:

Answer:

B) protons and neutrons.

Explanation:

The protons and neutrons are located in the nucleus of the atom and represent most of the 'mass' of the atom, that's their count that determine the 'mass' of an atom (like 12 for Carbon).

The electrons rotate around the nucleus and have a negligible mass.

Answer:

B

Explanation:

Protons have a positive charge, while neutrons have a no charge (neutral). There two components make up the nucleus. While electrons go around the nucleus creating an electron cloud.

Answer:

200000 cm are in 2 km

Explanation:

Answer:

200000 cm are in 2 km

hope this helps pls make this the brainliest

i believe it's C but i'm not completely sure

The answer is a change in the direction of light when it goes from one medium into a different medium.

Answer:

3.605N

Explanation:

From the diagram attached, the resultant force can be calculated using pythagoras theorem,

R² = F1² + F2²

R² = 3² + 2²

R² = 9 + 4

R² = 13

R = 3.605N

Note: the square root of R was taken

Answer:

-300 Hz

-450 Hz

Explanation:

As we know that frequency of nth harmonic mode is known as

[tex]f_n = \frac{nv}{2L}[/tex]

now we know that for fundamental mode of frequency we will have

n = 1

[tex]f_o = \frac{v}{2L}[/tex]

so we will have

[tex]f_n = n f_o[/tex]

now given that

[tex]f_o = 150 Hz[/tex]

and also we have

n = integer

so we will have

n = 2

[tex]f = 300 Hz[/tex]

n = 3

[tex]f = 450 Hz[/tex]

Answer:

300 and 450

Explanation:

Answer:

Hypocalcemia is the correct answer.

Explanation:

This disease, hypocalcemia, is usually known as calcium deficiency disease, which happens when calcium levels in the blood are low. If this disease is not taken care of properly, it can lead to cataracts, alteration in the brain, or even osteoporosis (the bones become brittle.)

Answer:

2.25 N upwards

Explanation:

Answer:

800 N/C to the right

Explanation:

The equation that relates force on a charge, electric field and charge is

[tex]F=qE[/tex]

where

F is the force acting on the charge

q is the charge

E is the electric field

In this problem, we have

[tex]E=15 N/C[/tex] is the electric field

[tex]q=-0.15 C[/tex] is the charge

Substituting into the formula, we find the force

[tex]F=(-0.15 C)(15 N/C)=-2.25 N[/tex]

Concerning the direction:

- The electric field and the force have same directions if the charge is positive

- The electric field and the force have opposite directions if the charge is negative

Here the charge is negative, so the electric field has opposite direction to the force: therefore, it must be upwards.

Answer:

A would definately be the correct answer

Explanation:

Answer: A. Proteins expressing color in butterfly wings mutate to create camouflaging abilities of butterflies.

Explanation:

Adaptation can be define as the changes occurring in living organisms in their physiology, morphology, and genomic. These adaptations allow organisms to survive in adverse environment.

A. is the correct option. It is an example of physiological adaptation. The color of butterfly wings will change due to protein expression. Thus help in camouflaging the predators by color change.

Answer:

paper burned and turned into smoke...

Explanation:

When a chemical reaction has taken place that means that whatever the starting variable is, (in this case it was the paper) then it cannot go back to its original state... you can also tell if a chemical reaction has taken place if the test releases any kind of gas, if there is a temperature change, or if there is a color change. Which this time it changed from paper into smoke which is a gas

Hope This Helps

Answer:

paper burned and turned into smoke

Explanation:

Because it changes how i looks and the chemichals change.

Answer:

18 m, 7.9 m

Explanation:

In the y direction:

y = y₀ + v₀ᵧ t + ½ aᵧ t²

0 = 0 + (v₀ sin 45°) t + ½ (-g) t²

0 = t (v₀ sin 45° - ½ g t)

t = 0, t = 2v₀ sin 45° / g

In the x direction:

x = x₀ + v₀ t + ½ at²

x = 0 + (v₀ cos 45°) t + ½ (0) t²

x = v₀ cos 45° t

Substituting for t:

x = v₀ cos 45° (2v₀ sin 45° / g)

x = v₀² / g

When g = 9.80 m/s², x = 3.0 m:

3.0 = v₀² / 9.80

v₀² = 29.4

On the moon, when g = 9.80/6:

x = 29.4 / (9.80 / 6)

x = 18 m

As you can see, x is inversely proportional to g, so 1/6 the gravity means 6 times the distance.  So on Mars:

x = 3 / 0.38

x = 7.9 m

Answer:

Explanation:

That is exactly what it does. That's how it is set up.

True

An electrocardiogram (ECG or EKG) is a diagnostic tool used to record the electrical activity of the heart. It involves the use of an electrocardiograph and electrodes. However, it has certain limitations and cannot reveal the effectiveness of the heart's pumping action.

An electrocardiogram (ECG), also often abbreviated as EKG, is a recording of the electrical activity of the heart that can be used to diagnose irregular heart function. Through the placement of surface electrodes on the body, the complex, compound electrical signal of the heart can be recorded. These signals are created from the processes of depolarization and repolarization, especially in the heart.

The standard electrocardiograph uses between 3 and 12 leads to capture this information. These leads may refer to the cables from the electrodes to the electrical recorder, but typically, it refers to the voltage difference between two electrodes. Sometimes, a patient might need to wear a portable device known as a Holter monitor to continuously monitor the heart's electrical activity.

It's important to note that the ECG has limitations. For instance, not all areas suffering a myocardial infarction (MI) may show up on the ECG. It also will not reveal the effectiveness of the heart's pumping action, which requires further tests such as an echocardiogram or nuclear medicine imaging.

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Answer:

We experience interference while listening to the radio. A radio station works by sending and receiving radio waves. Since the radio waves are being interfered with other waves which must have a wave nature.

The interference is the net result of two individual waves. It can be constructive or destructive interference and is the property of waves and not particles.

This interference is an example of electromagnetic radiation. Thus we experience wave behavior of electromagnetic radiation in our daily communications.

Answer: wave behavior

Explanation:

An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. It behaves exactly like a permanent magnet, like those magnets commonly used to stick items to our fridge.

To make a permanent magnet we need:

- One iron nail ( Could be fifteen centimeters (6 in) long )

- Three meters (10 ft) of copper wire

- One or more D-cell batteries

To make the electromagnet, we need to:

1. Wrap the Wire Around the Nail

2. Connect the Battery

And you are all set!

1. Rocks near mid-ocean ridge were younger than rock near trenches. Rocks away from the mid-oceanic ridges are relatively older than those near it.  

Additionally, the older rocks are denser and thicker compared to thinner and less dense rocks near the mid-oceanic ridge.

2. Matching bands of magnetic rocks were found on either side the mid-ocean ridge; bands like tree rings - record changes in earth's magnetic field over time.

This means sea floor contains different rocks based on ages and are positioned equally in opposite directions. This indicates that there is constant movement and spreading of rocks on the ocean floor.

3. Earthquake data showed oceanic crust is sinking on to the mantle at trenches.  

Keywords: Seafloor spreading, evidence of seafloor spreading  

Level: High school  

Subject: Geography  

Topic: Geology  

Sub-topic: Seafloor spreading  

The main evidence for sea-floor spreading comes from several sources of geological and geophysical data, which collectively support the idea that new oceanic crust is continually forming at mid-ocean ridges and spreading away from these ridges over time.

Some of the key evidence for sea-floor spreading includes:

1. Oceanic Bathymetry: The mapping of the ocean floor using sonar and other techniques has revealed the existence of mid-ocean ridges, underwater mountain ranges that extend for thousands of kilometers through the world's oceans. These ridges exhibit a symmetrical pattern of magnetic anomalies on either side, indicating a continuous process of seafloor spreading.

2. Paleomagnetic Evidence: Scientists have discovered that the rocks making up the ocean floor contain records of the Earth's past magnetic field. As the magma cools and solidifies at mid-ocean ridges, magnetic minerals within the rocks align with the prevailing magnetic field at the time. By studying the magnetic orientation of these rocks, scientists found that the magnetic patterns are symmetrical on either side of mid-ocean ridges, supporting the idea of sea-floor spreading.

3. Age of Oceanic Crust: Radiometric dating of rock samples collected from the ocean floor reveals that the rocks get progressively older as one moves away from mid-ocean ridges. The youngest rocks are found near the ridges, while the oldest rocks are located farther away. This age progression is consistent with the idea of seafloor spreading, where new crust is continuously formed at the ridges and moves away from the center.

4. Magnetic Reversals: The study of magnetic anomalies in the oceanic crust has revealed periods of magnetic reversal, where the Earth's magnetic field has flipped in the past. These magnetic reversals are recorded in the ocean floor rocks as bands of alternating magnetic orientations. The symmetrical pattern of magnetic anomalies on either side of mid-ocean ridges is evidence of the spreading of oceanic crust and the preservation of these magnetic records.

5. Earthquake and Volcanic Activity: Seismic activity, including earthquakes and volcanic eruptions, is concentrated along mid-ocean ridges, indicating the presence of tectonic activity and the upwelling of magma to form new oceanic crust.

By considering these lines of evidence together, scientists have developed the theory of sea-floor spreading, which forms an essential part of the broader theory of plate tectonics, explaining the movement of the Earth's lithospheric plates over geological time scales.

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Answer:

age structure

Explanation:

The variable would be most useful in determining the number of people eligible for retirement benefits in a certain year is age criteria.

When an employee reaches his age of retirement from work, he needs to stay at home and perform no work in organization.

So, the age criteria is an important factor to decide the retirement of a person. He is then eligible for all the retirement benefits offered by the private sector organization or government.

Thus, variable would be most useful in determining the number of people eligible for retirement benefits in a certain year is age criteria.

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The displacement from point A to point B is the length of the shortest path between them along with the direction from A to B.

Choice D

When a body is moving on a linear path, the displacement is the shortest path between two points, including both distance and direction. The correct option is D.

The distance is the total path traveled by the particle or an object on a linear path.

When the particle has moved from point A to B straight on the path, the distance is equal to the displacement. When the particle takes a U turn or deflects from the path to left or right or any direction, the displacement is less than the distance. The displacement is measured as the distance between the initial and final point.

Thus, when a body is moving on a linear path, the displacement is the shortest path between two points, including both distance and direction. The correct option is D.

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Answer:

800 N/C to the right

Explanation:

The relationship between electric force, electric field and charge is

[tex]E=\frac{F}{q}[/tex]

where

E is the electric field

F is the force acting on the charge

q is the charge

In this problem, we have

[tex]F = 0.040 N[/tex] is the force

[tex]q=+50 \mu C=+50 \cdot 10^{-6}C[/tex] is the charge

Substituting into the formula, we find the electric field magnitude

[tex]E=\frac{0.040 N}{+50 \cdot 10^{-6}C}=800 N/C[/tex]

Concerning the direction:

- The electric field and the force have same directions if the charge is positive

- The electric field and the force have opposite directions if the charge is negative

Here the charge is positive, so the electric field has same direction as the force: therefore, to the right.

"When we swim, we apply force and push the water backward with the help of our hands. In response to this action, the water pushes us forward with an equal force. Thus, in order to move forward and swim, the swimmer pushes the water backward."

-Newton's 3rd law

1) A. 2

The electrostatic force between two objects 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 charges of the two objects

r is the separation between the two objects

In this problem, the charge of one object is doubled, so

[tex]q_1' = 2q_1[/tex]

Therefore the new force is

[tex]F'=k\frac{q_1' q_2}{r^2}=k\frac{(2q_1)q_2}{r^2}=2(\frac{kq_1 q_2}{r^2})=2F[/tex]

So, the force will double.

2) D. 1/4

Using the same formula, the electrostatic force between the two objects is:

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

In this problem, the distance between the two objects is doubled, so

[tex]r' = 2r[/tex]

Therefore the new force is

[tex]F'=k\frac{q_1 q_2}{(r')^2}=k\frac{q_1 q_2}{(2r)^2}=\frac{1}{4}(\frac{kq_1 q_2}{r^2})=\frac{F}{4}[/tex]

So, the force will decrease to 1/4 of its original value.

3) 4/9

Using the same formula, the electrostatic force between the two objects is:

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

In this problem, the amount of charge on both objects doubles, so

[tex]q_1' = 2q_1[/tex]

[tex]q_2' = 2q_2[/tex]

Also, the distance is tripled

[tex]r' = 3r[/tex]

Therefore the new force is

[tex]F'=k\frac{q_1' q_2'}{(r')^2}=k\frac{(2q_1) (2q_2)}{(3r)^2}=\frac{4}{9}(\frac{kq_1 q_2}{r^2})=\frac{4}{9}F[/tex]

So, the force will decrease to 4/9 of its original value.