The internal resistance of a primary cell is 42. It generates a current of 0.2 A in an external resistance of 21 n. The rate at which chemical energy to consumed in providing current is

• 1 J/s

• 5 J/s

• 0.42 J/s

• 0.8 J/s

22.

220 V, 50 Hz, AC source is connected to an inductance of 0.2 Hand a resistance of 20 Ω in series. Whatis the current in the circuit?

• 3.33 A

• 33.3 A

• 5 A

• 10 A

In 0.2 s, the current in a coil increases from 2.0 A to 3.0 A. If inductance of coil is 60 mH, then induced current in external resistance of 3 Ω will be

• 1A

• 0.5 A

• 0.2 A

• 0.1 A

A galvanometer acting as a voltmeter should have

• low resistance in series with its coil

• low resistance in parallel with its coil

• high resistance in series with its coil

• high resistance in parallel with its coil

The equivalent resistance across A and B is

• 2 Ω

• 3 Ω

• 4 Ω

• 5 Ω

At room temperature, copper has free electron density of 8.4 x 10²⁸ m^-3, The electron drift velocity in a copper conductor of cross-sectional area of 10^-6 m² and carrying a current of 5.4 A, will be

• 4 ms^-1

• 0.4 ms^-1

• 4 cm s^-1

• 0.4 mm s^-1

A uniform wire of resistance R and length L is cut into four equal parts, each of length  L/4 which are then connected in parallel combination. The effective resistance of the combination will be

• R

• 4R

• $\frac{\mathrm{R}}{4}$

• $\frac{\mathrm{R}}{16}$

A 5 amp fuse wire can withstand a maximum power of 1 W in circuit. The resistance of the fuse wire is

• 0.2 Ω

• 5 Ω

• 0.4 Ω

• 0.04 Ω

Two equal negative charges - q are fixed at the point (0, a) and (0, - a) on the y-axis. A positive charge Q is released from rest at the point (2a, 0) on the x-axis. The charge wil

• execute SHM about the origin

• move to the origin and remain at rest

• move to infinity

• execute oscillatory but not SHM

Light travels faster in air than that in glass. This is accordance with

• wave theory of light

• corpuscular theory of light

• neigther (a) nor (b)

• Both (a) and (b)