Quiz 28
Multiple-choice questions on capacitors and inductance
1.
The capacitance of a capacitor is the ratio
(a)
charge to p.d. between plates
(b)
p.d. between plates to plate spacing
(c)
p.d. between plates to thickness of dielectric
(d))
2.
p.d. between plates to charge
The p.d. across a 10 μF capacitor to charge it with 10 mC is:
(a) 10 V
3.
(b) 1 kV
7.
8.
(b) 0.5 μF
(d) 6 μF
Four 2 μF capacitors are connected in series. The equivalent capacitance is:
(a) 8 μF
(c) 2 μF
6.
(b) 0.1 C
(d) 0.01 μC
Four 2 μF capacitors are connected in parallel. The equivalent capacitance is:
(a) 8 μF
(c) 2 μF
5.
(d) 100 V
The charge on a 10 pF capacitor when the voltage applied to it is 10 kV is
(a) 100 μC
(c) 0.1 μC
4.
(c) 1 V
(b) 0.5 μF
(d) 6 μF
State which of the following is false. The capacitance of a capacitor
(a)
is proportional to the cross-sectional area of the plates
(b)
is proportional to the distance between the plates
(c)
depends on the number of plates
(d)
is proportional to the relative permittivity of the dielectric
Which of the following statements is false?
(a)
An air capacitor is normally a variable type
(b)
A paper capacitor generally has a shorter service life than most other types of capacitor
(c)
An electrolytic capacitor must be used only on a.c. supplies
(d)
Plastic capacitors generally operate satisfactorily under conditions of high temperature
The energy stored in a 10 μF capacitor when charged to 500 V is:
(a) 1.25 mJ
(c) 1.25 J
(b) 0.025 μJ
(d) 1.25 C
Science for Engineering. 978-1-138-82688-5, © John Bird. Published by Taylor & Francis. All rights reserved.
10.
11.
12.
The capacitance of a variable air capacitor is at maximum when
(a)
the movable plates half overlap the fixed plates
(b)
the movable plates are most widely separated from the fixed plates
(c)
both sets of plates are exactly meshed
(d)
the movable plates are closer to one side of the fixed plate than to the other
When a voltage of 1 kV is applied to a capacitor, the charge on the capacitor is 500 nC. The capacitance
of the capacitor is:
(a) 2 × 109 F
(b) 0.5 pF
(c) 0.5 mF
(d) 0.5 nF
When a magnetic flux of 10 Wb links with a circuit of 20 turns in 2 s, the induced e.m.f. is:
(a) 1 V
(b) 4 V
(c) 100 V
(d) 400 V
A current of 10 A in a coil of 1000 turns produces a flux of 10 mWb linking with the coil. The coil
inductance is:
(a) 106 H
(c) 1 μ H
13.
14.
(b) 1 H
(d) 1 mH
Which of the following statements is false? The inductance of an inductor increases:
(a)
with a short, thick, coil
(b)
when wound on an iron core
(c)
as the number of turns increases
(d)
as the cross-sectional area of the coil decreases
Self-inductance occurs when:
(a)
the current is changing
(b)
the circuit is changing
(c)
the flux is changing
(d)
the resistance is changing
Answers
1. (a) 2. (b) 3. (c) 4. (a) 5. (b)
6. (b) 7. (c) 8. (c) 9. (c) 10. (d)
11. (c) 12. (b) 13. (d) 14. (a)
9.