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
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
C.
4 Ω
The equivalent circuit can be redrawn as
We have
So, the given circuit is a balanced Wheatstone's bridge.
Hence, the equivalent resistance
=
RAB = 4 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
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)