Figure shows three spherical and equipotential surfaces A, B and C round a point charge q. The potential difference VA − VB = VB − VC. If t1 and t2 be the distance between them. Then
t1 = t2
t1 > t2
t1 < t2
t1 ≤ t2
C.
t1 < t2
Three capacitors of capacitances 1 µF, 2 µF and 4 µF are connected first in a series combination, and then in a parallel combination. The ratio of their equivalent capacitances will be
2 : 49
49 : 2
4 : 49
49 : 4
A fully charged capacitor has a capacitance C. It is discharged through a small coil of resistance wire embedded in a thermally insulated block of specific heat capacity s and mass m. If temperature of the block is raised by ΔT, the potential difference V across the capacitor is
In the given figure, a hollow spherical capacitor is shown. The electric field will not be zero at
r < r1
r1 < r2
r < r2
r1 < r < r2
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 capacitor of capacitance 5 µF is connected as shown in the figure. The internal resistance of the cell is 0.5 Ω. The amount of charge on the capacitor plates is
80 µC
40 µC
20 µC
10 µC
Two identical cells of the same emf and same internal resistance give the same current through an external resistance 22, regardless of whether they are connected in series or parallel. The internal resistance of the cell is
1 Ω
2 Ω
3 Ω
4 Ω
Six equal resistance are connected between points P, Q and R as shown in the figure. Then the net resistance will be maximum between
P and Q
Q and R
P and Q
only two points