CBSE
Multiple Choice QuestionsA 30 µF capacitor is charged by a constant current of 30 mA. If the capacitor is initially uncharged, how long does it take for the potential difference to reach 400 V?
0.2 s
0.4 s
0.6 s
0.8 s
A condenser of capacitance 6 µF was originally charged to 10 V. Now potential difference is made 20 V. The increase in potential energy is
3×10-4 J
6×10-4 J
9×10-4 J
12×10-4 J
A gang capacitor is formed by interlocking a number of plates as shown in the figure.The distance between the consecutive plates is 0.885 cm and the overlapping area of the plates is 5 cm. The capacity of the unit is
1.06 pF
4 pF
6.36 pF
12.72 pF
What is the area of the plates of a 3F parallel plate capacitor, if the separation between the plates is 5 mm?
1.694 × 109 m2
4.529 × 109 m2
9.281 × 109 m2
12.981 × 109 m2
The outer sphere of a spherical air capacitor is earthed. For increasing its capacitance
vacuum is created between two spheres
dielectric material is filled between the two
spheres
the space between two spheres is increased
the earthing of the outer sphere is removed
Two identical capacitors each of capacitance 5 µF are charged to potentials 2 kV and 1 kV respectively. Their -ve ends are connected together. When the +ve ends are also connected together, the loss of energy of the system is
160 J
Zero
5 J
1.25 J
The ratio of magnetic potentials due to a magnetic dipole in the 'end on position' to that in the 'broad side on position' for the same distance from it is
zero
infinite
1
2
From the figure find the capacitance of the capacitor?
A parallel plate air capacitor has a capacitance C. When it is half-filled with a dielectric of dielectric constant 5, the percentage increase in the capacitance will be
400%
66.6%
33.3%
200%
If a unit positive charge is taken from one point to another over an equipotential surface, then
work is done on the charge
work is done by the charge
work done is constant
no work is done
