Knockout NEET May 2021 (One Month)
An exhaustive E-learning program for the complete preparation of NEET..
A student uses the circuit diagram of a potentiometer as shown in the figure
(a) For a steady current I passing through the potentiometer wire, he gets a null point for the cell and not for
. Give the reason for this observation and suggest how this difficulty can be resolved.
(b) What is the function of resistance R used in the circuit? How will the change in its value affect the null point?
(c) How can the sensitivity of the potentiometer be increased?
An exhaustive E-learning program for the complete preparation of NEET..
Master Maths with "Foundation course for class 10th" -AI Enabled Personalized Coaching -200+ Video lectures -Chapter-wise tests.
An exhaustive E-learning program for the complete preparation of JEE Main..
An exhaustive E-learning program for the complete preparation of NEET..
An exhaustive E-learning program for the complete preparation of JEE Main..
a) Both
have the positive terminal connected at A whereas negative terminal of
is connected to A. So null point is not obtained for cell 2
By interchanging the terminal of
, the difficulty can be resolved.
b) The resistance R protects the galvanometer by reducing the current flowing through it. As the null point is obtained for zero galvanometer reading, change in resistance R does not affect the null point reading.
c) By increasing the length of the potentiometer the sensitivity can be increased.