I thinks it’s 2...........
Answer: A) Transformer
Explanation: A Transformer is an apparatus, device or a component in a system that is used to convert high voltage into low voltage. It is used to either increase or decrease the voltage of an alternating current.
A transformer uses the basic principle of electro magnetic induction, having two or more coils, the voltage is changed from one coil to another but with thesame frequency as alternating current energy passes through them.
Answer: The unpolarized light's intensity is reduced by the factor of two when it passes through the polaroid and becomes linearly polarized in the plane of the Polaroid. When the polarized light passes through the polaroid with the plane of polarization at an angle
with respect to the polarization plane of the incoming light, the light's intensity is reduced by the factor of
(this is the Law of Malus).
Explanation: Let us say we have a beam of unpolarized light of intensity
that passes through two parallel Polaroid discs with the angle of
between their planes of polarization. We are asked to find
such that the intensity of the outgoing beam is
. To solve this we follow the steps below:
Step 1. It is known that when the unpolarized light passes through a polaroid its intensity is reduced by the factor of two, meaning that the intensity of the beam passing through the first polaroid is

This beam also becomes polarized in the plane of the first polaroid.
Step 2. Now the polarized beam hits the surface of the second polaroid whose polarization plane is at an angle
with respect to the plane of the polarization of the beam. After passing through the polaroid, the beam remains polarized but in the plane of the second polaroid and its intensity is reduced, according to the Law of Malus, by the factor of
This yields
. Substituting from the previous step we get

yielding

and finally,

(2.00 hours) x (3,600 seconds/hour) = 7,200 seconds
(9.00 minutes) x (60 seconds/minute) = 540 seconds
The record time = (7,200 + 540 + 21) = 7,761 seconds
Distance = (speed) x (time)
= (5.436 m/s) x (7,761 sec) =<span> 42,188.8 meters
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The official length of the marathon run is 42,195 meters.
If we divide that by the record time in the question, we get
5.4368... m/s .
Rounded to the nearest thousandth, that's 5.437 m/s.
If the question had given the speed as 5.437 instead of 5.436 ,
then we would have calculated the distance to be
(5.437 m/s) x (7,761 sec) =<span> 42,196.6 meters,
4.6 meters closer to the official distance than the answer we did get.
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2.0 meters The skateboarder has 2 forces acting upon him to slow him down. The forces are friction, and climbing against the gravitational acceleration. So let's calculate the magnitude of these forces to see how fast he's decelerated. The coefficient of kinetic friction is a multiplier to use against the normal force of the object. We can calculate the normal force by multiplying the mass of the object by the local gravitational acceleration and the cosine of the angle. So Df = 60 kg * 9.8 m/s^2 * cos(20°) * 0.30 Df = 60 kg * 9.8 m/s^2 * 0.939692621 * 0.30 Df = 60 kg * 9.8 m/s^2 * 0.939692621 * 0.30 Df = 165.7617783 kg*m/s^2 Df = 165.7617783 N
The second amount of force is that caused by gravitational acceleration while climbing. That is determine by the amount of height gained for every meter along the slope. We can calculate that using the sine of the angle. So
Dg = 60 kg * 9.8 m/s^2 * sin(20°)
Dg = 60 kg * 9.8 m/s^2 * 0.342020143
Dg = 201.1078443 kg*m/s^2
Dg = 201.1078443 N
So the amount of force decelerating the skateboarder is:
F = Df + Dg
F = 165.7617783 N + 201.1078443 N
F = 366.8696226 N
Now let's determine how much kinetic energy needs to be dissipated. The equation is
E = 0.5 MV^2
So we'll substitute the known values and calculate
E = 0.5 MV^2
E = 0.5* 60 kg * (5 m/s)^2
E = 0.5* 60 kg * 25 m^2/s^2
E = 750 kg*m^2/s^2
E = 750 J
Now let's divide the energy by the force.
750 kg*m^2/s^2 / 366.8696226 kg*m/s^2 = 2.04432298 m
Rounding to 2 significant figures gives a distance of 2.0 meters.