Physics Final Exam Missed Multiple Choice Questions

How does a tape recorder work?

Tape players work by inducing current from the motion of a magnet past a wire.

When is back emf at its maximum.

The back emf is at a maximum when the motor speed is at a maximum.

Review the right-hand rule.

Review the right-hand rule.

The current in a pure resistor is at a ___ degree angle with the applied voltage.

The current in a pure resistor is at a 0 degree angle with the applied voltage.

Is a current induced in the secondary coil if the input to the transformer is constant?

The current in the secondary is only induced if the input to the transformer is changing. Here it is constant so the current of the secondary is 0A.

Can an electromagnetic wave exceed the speed of light?

The speed of light is recognized as the cosmic speed limit. Nothing can cause an electromagnetic wave to move faster than that speed.

As the angle of incidence for a ray hitting a reflective surface is increased it what angle will it eventually approach?

As the angle of incidence for a ray hitting a reflective surface is increased it will approach the angle of a flat line, ie 180∘.

What values are included in Einstein’s principle of special relativity?

You are correct that Einstein predicted that the measured values for time and length were included in his special relativity calculations. Mass was also predicted through these calculations.

When the wavelength of an incident monochromatic light beam becomes shorter, what happens to the work function?

When the wavelength of an incident monochromatic light beam becomes shorter, the work function of a target material in a phototube will increase.

ϕ=hf−K

Example:

Original: ϕ=6(1/4)−2= 0.5

New: ϕ=6(1/2)−2= 1

So, a shorter wavelength = larger work function.

Does time dilation or length contraction occur with muons?

Interestingly, it is space itself that contracts. The muons are traveling at such a high speed that they experience a length contraction in the space around them and do not need to travel the distance in the conventional way we are familiar with.