Question

The arm PQ can revolve with uniform speed continuously about P round the circular uniform potentiometer track XYZ. The voltage between RS will vary with respect to lime:

(A) Sinusoidally
(B) Linearly
(C) Rectangularly
(D) Like saw tooth

Answer 1

We know that a potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat. A potentiometer circuit can be used for comparing and measuring potential differences, the principle of action being that the unknown EMF is measured by balancing it against a known potential difference. Potentiometers are commonly used to control electrical devices such as volume controls on audio equipment. Potentiometers operated by a mechanism can be used as position transducers, for example, in a joystick.

Complete step-by step answer:
As the voltage between $RS\text{ }\left( V \right)\,\propto \,$Resistance between P and Z.
Arm PQ is revolving uniformly so resistance between P and Z is changing uniformly
Let resistance XZ = R.
So, we can write resistance between P and Z as the function of time is $r=R-kt$.
Where k is some constant and r is resistance between P and Z which is an equation of decreasing straight line.
As arm comes to point Z resistance r = 0 and again it stands from R as it comes to point X.

Hence, the correct answer is Option D.

Note: We should know that the sawtooth wave or we can say saw wave is a kind of non-sinusoidal waveform. It is so named based, particularly bowed string instruments like violins and cellos, since the slip-stick behaviour of the bow drives the strings with a sawtooth-like motion. The convention is that a sawtooth wave ramps upward and then sharply drops. In a reverse or inverse sawtooth wave, the wave ramps downward and then sharply rises. It can also be considered the extreme case of an asymmetric triangle wave. Sawtooth waves are known for their use in music. The sawtooth and square waves are among the most common waveforms used to create sounds with subtractive analog and virtual analog music synthesizers.
It should also be known to us that the sawtooth wave is the form of the vertical and horizontal deflection signals used to generate a raster on CRT-based television or monitor screens. Oscilloscopes also use a sawtooth wave for their horizontal deflection, though they typically use electrostatic deflection.