Question

If the jockey is touched at a point on the wire 1.0 cm away from the balance point, then the galvanometer (G = 1 kΩ) will show a current equal to

(a)   2 μA 

(b)   4 μA 

(c)   6 μA 

(d)   8 μA 

Answer 1

Correct option     6 μA 

Explanation:

Potential gradient across the wire : 0.6 mV/mm = 6 mV/cm 

Potential difference across 1 cm length of the wire : 6 x 1 = 6 mV

Resistance of the galvanometer : 1 kΩ

Current through the galvanometer : i = v/G = 6 x 10^-3/1 x 10^-3

A large number of pendulums with identical bobs (mass m) but varying lengths are suspended from a thick thread. Another pendulum of heavier bob (mass M) is also suspended from the same thread as shown.

This pendulum with the heavier bob is used as a driver to drive the other pendulums called driven pendulums. Assume that the amplitude of the driver is maintained constant (by some suitable mechanism). Let the frequency of the driver be f_o