how much work must you do to push a 12 kg k g block of steel across a steel table at a steady speed of 1.3 m/s m / s for 6.1 s s ? the coefficient of kinetic friction for steel on steel is 0.60.

An Electromagnetic wave has a frequency of 7.57 x 10^14 Hz. Its wavelength can be found using the formula:c = λfwhere c is the speed of light, λ is the wavelength, and f is the frequency.

Substituting the given values in the formula, we have:c = 3 x 10^8 m/sf = 7.57 x 10^14 Hzλ = ?λ = c/f = (3 x 10^8 m/s)/(7.57 x 10^14 Hz)= 3.95 x 10^-7 mTherefore, the wavelength of the electromagnetic wave is 3.95 x 10^-7 m.

To determine the part of the spectrum this wave belongs to, we can use the electromagnetic spectrum.The electromagnetic spectrum is a range of frequencies of electromagnetic radiation, which includes radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

The frequency of the given electromagnetic wave falls within the visible light spectrum, making it a light wave. Therefore, the electromagnetic wave belongs to the visible light part of the spectrum.

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The rate at which the Sun emits energy is calculated using P = σ * A * T⁴. The fraction of emitted energy intercepted by Earth is (π * R_earth²) / (4 * π * R_earth-sun²). The solar constant is P * Fraction.

Step 1: Use the Stefan-Boltzmann Law
The Stefan-Boltzmann Law states that the power (energy emitted per unit time) of a blackbody is given by:
P = σ * A * T⁴
where P is the power, σ is the Stefan-Boltzmann constant (5.67 x 10⁻⁸ W/m²K⁴), A is the surface area, and T is the effective surface temperature.

Step 2: Calculate the surface area of the Sun
The surface area of a sphere is given by:
A = 4 * π * R²
where R is the radius. Since the diameter is given, we can find the radius as half of the diameter:
R = diameter / 2

Step 3: Calculate the power emitted by the Sun
Using the surface area and temperature, calculate the power:
P = σ * A * T⁴

Step 4: Calculate the fraction of emitted energy intercepted by Earth
The fraction of emitted energy intercepted by Earth can be found by calculating the ratio of the cross-sectional area of Earth to the surface area of a sphere with a radius equal to the Earth-Sun distance.
Fraction = (π * R_earth²) / (4 * π * R_earth-sun²)

Step 5: Estimate the solar constant
The solar constant is the amount of solar energy received per unit area at the mean Earth-Sun distance. It can be calculated using the power emitted by the Sun and the fraction of emitted energy intercepted by Earth:
Solar constant = P * Fraction

By following these steps, you can estimate the rate at which the Sun emits energy, the fraction of emitted energy intercepted by Earth, and the solar constant, given the diameter and effective surface temperature of the Sun and the mean Earth-Sun distance.

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The first four harmonics of a violin string vibrating at 400 Hz are 400 Hz, 800 Hz, 1200 Hz, and 1600 Hz, with each harmonic having a frequency that is a multiple of the fundamental frequency.

The first four harmonics of a violin string, which has a fundamental frequency of 400 Hz, can be computed as follows: The basic frequency, 400 Hz, is represented by the first harmonic, where n = 1. The frequency of the second harmonic (n = 2) is two times that of the main frequency. Consequently, the second harmonic's frequency is: 400 Hz + 2 f1 = 2 = 800 Hz The frequency of the third harmonic (n = 3) is three times that of the main frequency. Consequently, the third harmonic's frequency is: 400 Hz + 3 f1 = 3 = 1200 Hz The frequency of the fourth harmonic (n = 4) is four times that of the main frequency. Consequently, the fourth harmonic's frequency.

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The angular momentum of an object conserved A.  if there is no net torque acting on it.

Angular momentum is defined as the rotational analog of linear momentum, which is a measure of the amount of rotation an object has. The law of conservation of angular momentum states that the angular momentum of an object is conserved when there is no external torque acting on the object.

Mathematically, it can be expressed as, L = IωWhere L is the angular momentum of an object, I is its moment of inertia, and ω is its angular velocity. The angular momentum of an object is conserved when there is no net torque acting on it. This means that the total external torque acting on an object must be zero. If there is no external torque acting on an object, its angular momentum will be conserved, meaning that it will remain constant in magnitude and direction over time.

If an object experiences a torque, its angular momentum will change, and the rate of change of angular momentum will be equal to the magnitude of the torque acting on the object. Hence, if there is no net torque acting on an object, the angular momentum of that object will be conserved. An object that has no net force acting on it is not necessarily conserved, since it may still experience a torque that will cause its angular momentum to change.

However, if an object is a point particle, it can be treated as having zero moments of inertia, and its angular momentum will be conserved if there is no net torque acting on it. Therefore the correct option is A

The Question was Incomplete, Find the full content below :

under what condition is the angular momentum of an object conserved?

a. if there is no net torque acting on it.

b.  if it is a point particle.

c. if there is no net force acting on it.

d. if there are no torques acting on it

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Explanation:

Using conservation of momentum

  the bullets momentum   must equal the rifle's momnetum

5 000 gm * v  = 50 gm * 100 m/s

v = 1 m/s

One of the most compelling pieces of evidence is the cosmic microwave background radiation (CMB), which is a faint glow of electromagnetic radiation that fills the entire universe.

This radiation is thought to be the afterglow of the Big Bang and is consistent with the predictions of the theory. Additionally, observations of the distribution and movement of galaxies in the universe suggest that the universe is expanding. Finally, the observed abundance of light elements in the universe, such as hydrogen and helium, is also consistent with the predictions of the Big Bang theory. Together, these observations provide strong evidence that the universe began with a sudden expansion from a singularity.

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System 2 has a higher temperature because the particles are moving with greater speed. The particles in System 2 have greater kinetic energy than System 1.

What is kinetic energy?

Kinetic energy is a form of energy that an object possesses by virtue of its motion. It is defined as the energy an object possesses due to its motion and is determined by its mass and velocity. The greater an object's mass and velocity, the greater its kinetic energy.

What is velocity?

Velocity is a vector quantity that describes the rate at which an object changes its position in a specific direction. It is defined as the displacement of an object per unit of time and is measured in meters per second (m/s) or other appropriate units of distance over time. Velocity takes into account both the speed of the object and its direction of motion, making it a more precise measurement than speed.

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Answer:

60 Ω

Explanation:

When when there is a series connection, the resistances of the resistors are added together;

R = R1 + R2 + R3

R = 20 Ω + 30 Ω + 10 Ω = 60 Ω

A mass of 1.53 kg is attached to a spring and the system is undergoing simple harmonic oscillations with a frequency of 1.95 hz and an amplitude of 7.50 cm. The total mechanical energy of the system is 0.198 J.

The total mechanical energy of a system undergoing simple harmonic oscillations can be calculated using the formula:

E = (1/2) kA²

where E is the total mechanical energy of the system, k is the spring constant, and A is the amplitude of the oscillation.

To calculate the spring constant, you can use the formula:

k = (4π²m)/T²

where m is the mass attached to the spring, and T is the period of the oscillation, which can be calculated using the formula:

T = 1/f

where f is the frequency of the oscillation.

Substituting the given values into these formulas, we have:

k = (4π² × 1.53) / (1/1.95)²= 70.59 N/m

E = (1/2) × 70.59 × (0.075)²= 0.198 J

Therefore,  0.198 J is the total mechanical energy of the system.

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Answer:

a patch of light appears at a specific point on the floor due to reflection from a nearby surface. This phenomenon occurs due to the law of reflection, which states that when light hits a surface, it reflects off at an angle equal to the angle at which it struck.

Explanation:

please follow po and u can ask me for help.

Jet streams are bands of high-speed wind found at elevations of 9-15 km. This wind current, referred to as jet streams, is formed by a combination of atmospheric temperature, Earth's rotation, and pressure differences in the atmosphere.

What are jet streams, Jet streams are fast-flowing, narrow air currents located in the upper atmosphere or the troposphere, generally around 8 to 9 miles high in the Earth's atmosphere.

They are formed due to the combination of the Earth's rotation, temperature, and atmospheric pressure.The temperature of the air in the atmosphere decreases with increasing altitude. Because the Earth's rotation is faster at the equator than at the poles, the temperature difference causes high-altitude air to flow from west to east, resulting in a jet stream.

The band of high-speed wind called the jet stream can influence the weather in the areas they pass over. They push high and low-pressure systems around, affecting weather patterns. Jet streams are caused by differences in atmospheric pressure, Earth's rotation, and atmospheric temperature.

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The person does 31.4 Joules of work when pulling the starter cord.

To calculate the work done by the person pulling the starter cord, we need to find the distance that the cord moves as it is pulled.

The circumference of the drum can be calculated as:

C = 2πr = 2 x 3.14 x 0.1m = 0.628m

So, each complete turn of the drum will wind or unwind the cord by a distance of 0.628m.

Assuming that the person pulls the cord with a constant force of 100N, the work done can be calculated as:

Work = Force x Distance

where distance is the length of cord pulled.

Since the cord is wound on the drum, the distance pulled will be equal to the length of the cord unwound from the drum.

Length of cord unwound = π x diameter of drum

= π x 10cm = 0.314m

Therefore, the work done by the person is:

Work = Force x Distance = 100N x 0.314m = 31.4 Joules (J)

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The forces operating on the thing in question are considered to be into equilibrium when there is no net force on it.

The rate at which velocity changes is referred to as acceleration. velocity change over time is measured by acceleration (a). As a result, any change in direction or speed will result in a change to velocity, which will then result in acceleration.

According for the equation that a = v/t, acceleration (a) equals the product of the alteration in velocity (v) and a change in time (t).

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The car battery has a rating of 89Ah, which implies that it can supply a current of 89 A for 1 hour before being completely discharged. If you leave your headlights on until the battery is completely dead, the amount of charge that leaves the battery is 320400 coulombs.

The amount of charge that leaves the battery is given by:

C = I × t

where C is the charge, I is the current, and t is the time taken.

In this case, the current I = 89 A and the time t = 1 hour = 3600 s

Therefore, the charge that leaves the battery is:

C = 89 A × 3600 s

C = 320400 C

Therefore, 320400 coulombs is The amount of charge that leaves the battery.

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According to fossil evidence, South America and Africa were formerly part of a single geographical mass.

The eastern Greenland and Appalachian mountain ranges' similarity is scientists evidence for the theory of continental drift. In rocks that are the same age but on continents that are currently far apart, ancient fossils of the same species of extinct plants and animals can be found.s.

The most convincing proof, in his opinion, that the two continents were formerly connected is the existence of identical fossil species along the coasts of South America and Africa.

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A 264 kg merry-go-round spinning at 24 rpm has its angular velocity reduced to 14.3 rpm after a 35.4 kg person jumps on.

To tackle this issue, we really want to utilize protection of precise energy. At first, the carousel is turning at a specific precise speed and has a specific snapshot of dormancy. At the point when John bounces onto the carousel, he expands the snapshot of inactivity, which makes the carousel delayed down. Notwithstanding, since precise energy is monitored, the result existing apart from everything else of dormancy and rakish speed should stay steady.

To begin with, we should track down the snapshot of idleness of the carousel:

I =[tex](1/2)mr^2[/tex]

where

m = 264 kg (mass of the carousel)

r = 1.385 m (span of the carousel, which is half of the width)

I = [tex](1/2)(264 kg)(1.385 m)^2[/tex] = 255 kg[tex]m^2[/tex]

Then, how about we convert the underlying precise speed of the carousel from rpm to rad/s:

w_i = (24 rpm)(2π rad/1 rev)(1 min/60 s) = 2.51 rad/s

The underlying precise force of the framework is then:

L_i = Iw_i = (255 kg [tex]m^2[/tex])(2.51 rad/s) = 642.05 kg [tex]m^2/s[/tex]

At the point when John hops onto the carousel, the snapshot of inactivity of the framework increments to:

I_f = I + m*[tex]r^2[/tex]

where

m = 35.4 kg (mass of John)

r = 1.385 m (span of the carousel)

I_f = (264 kg)[tex](1.385 m)^2[/tex] + (35.4 kg)[tex](1.385 m)^2[/tex]= 429.78 kg [tex]m^2[/tex]

To find the last precise speed of the framework, we can utilize protection of rakish energy:

L_i = L_f

Iw_i = I_fw_f

Settling for w_f, we get:

w_f = (Iw_i)/I_f = (255 kg [tex]m^2/s[/tex])(2.51 rad/s)/(429.78 kg [tex]m^2[/tex]) = 1.50 rad/s

At long last, we can change over the last precise speed from rad/s back to rpm:

w_f = (1.50 rad/s)(60 s/2π rad)(1 fire up/1 turn) = 14.3 rpm

Consequently, the rakish speed of the carousel, in rpm, after John hops on is 14.3 rpm.

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If Olaf catches the ball, the speed with which Olaf and the ball move afterward can be determined using the principle of conservation of momentum. The total momentum of a system remains constant if no external force acts on it.

the ball's momentum before being caught by Olaf equals the combined momentum of Olaf and the ball after the catch. The expression that represents this concept is pi= pf, where pi is the initial momentum of the ball (which is equal to the final momentum), and pf is the final momentum of the ball and Olaf. In general, momentum is defined as:p = mv where,m is the mass of the object in kg,v is the velocity of the object in m/sandp is the momentum of the object in kg m/s.Applying the conservation of momentum principle:pi= pf m1v1= m1v1'+m2v2', where,m1 is the mass of the ball,v1 is the velocity of the ball before being caught by Olaf,v1' is the velocity of the ball and Olaf after the catch,m2 is the mass of Olaf, andv2' is the velocity of Olaf after the catch.The velocity of Olaf before the catch is assumed to be zero because it is not mentioned in the problem statement. The problem statement asks for the velocity of Olaf and the ball after the catch, which we will represent asv1'.So, using the above formula, we get:0.5 × 3.0 kg × 20.0 m/s = 0.5 × 3.0 kg × v1' + 20.0 kg × 0 m/sHere,m1 = 0.5 kg, v1 = 20 m/s, m2 = 20 kg, andv2' = 0 m/sSolving forv1', we get:v1' = (0.5 × 3.0 kg × 20.0 m/s)/ (0.5 × 3.0 kg + 20.0 kg)= 2.73 m/sTherefore, if Olaf catches the ball, the speed with which Olaf and the ball move afterwards is 2.73 m/s.

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When a parallel-plate capacitor is connected to a battery, if the plate separation is doubled the stored energy decreases by a factor of 2 while the capacitor remains connected to the battery. The correct option is (c)

The stored energy in a capacitor can be computed from the amount of charge stored on the plates and the voltage difference between them.

It is given by the formula E=½QV, where E is the energy, Q is the charge, and V is the voltage between the plates.

A capacitor stores energy in its electric field, which is created by the charge distribution on its plates.

When the plate separation is increased while the capacitor is connected to a battery, the electric field inside the capacitor decreases since the voltage across it is constant. This results in a reduced potential energy, as well as a decrease in stored energy.

As a result, the stored energy of the capacitor is reduced by a factor of 2 when the plate separation is doubled, as the electric field in the capacitor decreases by half. Therefore,option (c) is correct.

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The magnitude of the force per meter of length on the wire is 6.375 N/m when the wire is carrying an 8.50-A current perpendicular to a 0.75-T uniform magnetic field.

The magnitude of the force per meter of length on a straight wire carrying an 8.50-A current when perpendicular to a 0.75-T uniform magnetic field can be calculated using the formula F = BIL, where F is the magnitude of the force, B is the magnetic field strength, I is current, and L is the length of the wire.

Substituting the given values, we get:

F = (0.75 T) x (8.50 A) x 1 m

F = 6.375 N/m

This force is known as the Lorentz force, which describes the force experienced by a charged particle, such as an electron when moving in a magnetic field. In this case, the moving charges are the electrons in the wire, and the magnetic field causes them to experience a force perpendicular to their direction of motion.

This force can be used in various applications, such as electric motors and generators, where the motion of electrons in a magnetic field is utilized to produce mechanical work or generate electricity.

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When the solenoid carries a current of 0.780 a, 0.00372 J energy is stored in its magnetic field

The energy stored in a magnetic field of an inductor (such as a solenoid) is given by:

U = (1/2) x L x [tex]I^2[/tex]

where U is the energy stored,

L is the inductance, and

I is the current flowing through the inductor.

To calculate the inductance of the solenoid, we can use the formula:

L = [tex]\frac{ (\mu_0 \times N^2 \times A)}{l}[/tex]

where [tex]\mu_0[/tex] is the permeability of free space (4π x [tex]10^{-7}[/tex] T·m/A),

N is the number of turns,

A is the cross-sectional area of the solenoid, and

l is the length of the solenoid.

The cross-sectional area of the solenoid is given by:

A = π x [tex]r^2[/tex]

where r is the radius of the solenoid (half of its diameter).

So, first, let's calculate the inductance:

r = 1.20 cm / 2 = 0.60 cm = 0.0060 m

A = π x [tex](0.0060 m)^2[/tex] = 1.13 x [tex]10^{-4}\: m^2[/tex]

l = 8.00 cm = 0.0800 m

N = 60

μ0 = 4π x [tex]10^{-7}[/tex] T·m/A

L = [tex]\frac{ (\mu_0 \times N^2 \times A)}{l}[/tex]

L = [tex]\frac{(4\pi \times 10^{-7} \times 60^2 \times 1.13 \times 10^{-4} ) }{0.0800 m}[/tex]

L = 0.0128 H

Now we can use the formula for the energy stored in the magnetic field:

U = (1/2) x L x [tex]I^2[/tex] = (1/2) x 0.0128 H x [tex](0.780 \:A)^2[/tex]

U  = 0.00372 J

Therefore, the energy stored in the magnetic field of the solenoid is 0.00372 J.

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The gravitational force on the object with a mass of 5 kg on the surface of the Earth is 49.05 N.

The equation that can help Stacy find the gravitational force on an object if she knows its mass is:

F = w = m x g

where:

F is the gravitational force (in Newtons, N)

m is the mass of the object (in kilograms, kg)

g is the acceleration due to gravity (in meters per second squared, [tex]m/s^2)[/tex]

The value of g varies depending on the location of the object, but on the surface of the Earth, it is approximately 9.81 [tex]m/s^2.[/tex]

To test the equation using a set of values from the table, let's say we have an object with a mass of 5 kg. Using the value of g on the surface of the Earth, we can calculate the gravitational force on the object as:

F = 5 kg x 9.81[tex]m/s^2[/tex]

F = 49.05 N.

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The required angle of principle maxima when wavelength and diffraction grating are given is calculated to be 15.07°.

The wavelength is given as 780 nm = 780 × 10⁻⁹ m

It is given that the diffraction grating contains 3300 lines per centimetre.

Distance between the slits d = 1 cm/3300 lines = 10⁻² m/3300 lines = 3×10⁻⁶ m

The angles of principle maxima are to be found out.

We know that,

d sin θ = m λ

where,

d is the distance between slits

θ is the angle with respect to the path of the incident light

m is the order of interference

sin θ = m λ/d

θ = sin⁻¹(m λ/d) =  sin⁻¹[(1× 780 × 10⁻⁹)/(3×10⁻⁶)] = sin⁻¹ (26× 10⁻²) = sin⁻¹(0.26) = 15.07°

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The logic gate in figure 5.88a is NAND gate. When two inputs are joined together it will act as a NOT gate. This is shown  in figure 5.88b.

A truth table is a table that shows the output of a logic gate for all possible combinations of its input values.

a. Truth table of NAND gate is:

A B Output

0 0 1

0 1 1

1 0 1

1 1 0

b. When one input each is given to two different NOT gates and these two gates are connected to an AND gate, a NOT gate is formed.

This is the truth table for these gates:

A B ~A ~B ~A AND ~B

0 0  1   1       1

0 1  1   0       0

1 0  0   1       0

1 1  0   0       0

As you can see from the truth table, the output of the AND gate is 1 (logic high) only when both inputs to the NOT gates are 0 (logic low). In all other cases, the output of the AND gate is 0 (logic low). Therefore, the output of the entire circuit is the negation of the input A. This is the behavior of a NOT gate.

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The image of the question is attached.

The focal length of the eyepiece lens should be 0.076 m to give a magnification of magnitude 250.According to the magnification formula, Magnification = focal length of the objective lens / focal length of the eyepiece lens.

Magnification = 250focal length of the objective lens = 19 m Magnification = focal length of the objective lens / focal length of the eyepiece lens.250 = 19 / focal length of the eyepiece lens Rearranging the above equation to get the focal length of the eyepiece lens: focal length of the eyepiece lens = 19 / 250focal length of the eyepiece lens = 0.076 m Therefore, the focal length of the eyepiece lens should be 0.076 m to give a magnification of magnitude 250.
To achieve a magnification of 250 with a telescope at Yerkes Observatory in Wisconsin, you can use the formula.

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Answer: Thursday, April 6, at 12:34 a.m.

Explanation:

You can determine if it is a lens or a mirror by checking if the light rays pass through or bounce off the optical device. If the rays pass through, it's a lens; if they bounce off, it's a mirror.

It seems that there is a missing diagram. However, I can provide you with general guidelines to determine the type of lens or mirror used to produce the image in a ray diagram.
1. Identify the object and image positions: Look at the diagram and locate the object (usually represented by an arrow) and the image (represented by another arrow, usually a different colour).
2. Determine if the image is real or virtual: If the image is formed by the actual intersection of light rays, it is a real image. If it is formed by the apparent intersection of light rays, it is a virtual image.
3. Determine if the image is upright or inverted: If the image arrow points in the same direction as the object arrow, the image is upright. If the image arrow points in the opposite direction, the image is inverted.
4. Determine if the image is magnified or reduced: Compare the height of the object and image arrows. If the image arrow is taller, the image is magnified. If the image arrow is shorter, the image is reduced.
Now, based on these properties, you can identify the type of lens or mirror used:
- If the image is real, inverted, and reduced, it could be a converging (convex) lens or a concave mirror.
- If the image is virtual, upright, and magnified, it could be a diverging (concave) lens or a convex mirror.
Once you have all this information, you can determine the type of lens or mirror used in the provided ray diagram.

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One phenomenon that we see when two monochromatic light source interfere constructively or destructively is the colors that are observed on the surface of a soap bubble. So option A is correct.

Constructive interference is when two light waves overlap and combines to form a larger wave. Destructive interference is when the waves cancel each other. Constructive interference occurs when the waves are in phase with each other, and destructive occurs when they are out of phase.

A soap bubble will have an internal and an external surface. Both these surface reflects light that falls in it regardless of the source. When these two reflected waves constructively or destructively interfere, we could see colors on the surface even the light reflected by both surfaces are white.

So the correct answer is option A.

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The complete question is

We have seen that two monochromatic light waves can interfere constructively or destructively, depending on their phase difference. One consequence of this phenomenon is

A) the colors you see when white light is reflected from a soap bubble.

B) the appearance of a mirage in the desert.

C) a rainbow.

D) the way in which Polaroid sunglasses work.

E) the formation of an image by a converging lens, such as the lens in your eye

Explanation:

Vf = Vo + at         Vo = 0        a = 9.81 m/s       t = 2

Vf = 0 + 9.81 (2) = 19.62 m/s

The velocity of the penny after it has fallen for 2 seconds is approximately 19.6 m/s.

When an object is dropped from rest, its velocity increases due to the acceleration of gravity. The acceleration of gravity on Earth is approximately 9.8 m/s².

The distance fallen by the penny after 2 seconds can be calculated using the formula:

d = 1/2 * g * t²

where d is the distance fallen, g is the acceleration due to gravity, and t is the time elapsed.

Substituting the values, we get:

d = 1/2 * 9.8 m/s² * (2 s)²

d = 19.6 m

Thus, the penny falls a distance of 19.6 meters in 2 seconds.

The velocity of the penny can be calculated using the formula:

v = √(2 * g * d)

where v is the velocity of the penny and d is the distance fallen.

Substituting the values, we get:

v = √(2 * 9.8 m/s² * 19.6 m)

v = √(384.16)

v = 19.6 m/s (approximately)

Therefore, the penny's speed is around 19.6 meters per second when it has been falling for 2 seconds.

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When light transmits through a refractive medium from air (like an air-water or an air-plastic interface) the speed of light decreases, while its frequency and wavelength remain constant.

Light is an electromagnetic wave that travels at a constant speed through a vacuum or a transparent medium. The frequency, wavelength, and speed of light are characteristics of this wave.

When light enters a refractive medium, such as air or water, it bends because its velocity changes due to the refractive index of the medium it is passing through.

Speed of light in different mediums

The speed of light is always slower when it passes through a refractive medium.

Light's frequency and wavelength remain constant

When light travels from air to another medium, such as water or plastic, its frequency and wavelength remain constant. Because these variables are properties of the wave and not influenced by the medium, this is the case.

When light enters a denser medium, the distance between its peaks remains constant, so its wavelength remains constant.

Similarly, because frequency is the number of peaks passing through a point per unit of time, it remains constant regardless of the medium.

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