Slide 1 / 25
1 The induced emf in a closed coil of wire, according to Faraday’s Law, is proportional to:
A I
B II
C II and II
D III and IV
E IV
I. The magnitude of the magnetic flux
II. The magnetic flux density
III. The number of turns
IV. The rate of change of magnetic flux
Slide 2 / 25
2 A changing magnetic field B induces an emf Ɛ in a coil of radius R. What is the induced emf in the coil of radius 2R?
A ε
B 2ε
C 4ε
D ε /2
E ε /4
Slide 3 / 25
3 A uniform magnetic field is distributed in a space of a circle of radius r. The changing field induces an emf Ɛ in the loop with the radius r. What is the induced emf in the loop with the radius 2r?
A ε
B 2ε
C 4ε
D ε /2
E ε /4
Slide 4 / 25
4 The number of turns in a long solenoid is doubled, how does the inductance of the solenoid change?
A It doesn't change
B It doubles
C It quadruples
D It is cut to a half
E It is cut to a quarter
Slide 5 / 25
5 Which of the following is true about the inductors?
A I
B III
C I and II
D II and III
E All of the above
I. They store energy over a long time
II. They resist the flow of current through it
III. They can produce a magnetic field
Slide 6 / 25
6 Which of the following can act as an inductor?
A I
B III
C I and II
D II and III
E All of the above
I. A long coil
II. A long wire
III. A conducting sphere
Slide 7 / 25
7 At time t =0 the switch is closed. Which of the following graphs best describes the voltage V across the resistance R as a function of time t?
A B
CD
E
Slide 8 / 25
8 If L is inductance measured in H (Henry), what is 1 H is equivalent to?
A 1 Vs/A
B 1 A/Vs
C 1 AV/s
D 1 As/V
E 1 s/AV
Slide 10 / 25
10 In the circuit above, what is the instantaneous current at point P after the switch is closed?
A ε/R
B 2ε/R
C ε/2R
D Lε/R
E 0
Slide 11 / 25
11 In the circuit above, what is the current at point P after the switch is closed for a long time?
A ε/R
B 2ε/R
C ε/2R
D Lε/R
E 0
Slide 12 / 25
12 The switch is closed for a long time in the circuit above, what is the energy stored in the inductor?
A Lε/2R
B Lε2/2R2
C Lε2/2R
D Lε/2R2
E L2ε2/2R
Slide 13 / 25
13 An electric circuit consists of a battery of emf Ɛ, a resistor R and an inductor L. Which of the following represents the time constant?
A R/L
B RL
C ε/RL
D ε/L
E L/R
Slide 14 / 25
14 An electric circuit consists of a battery of emf Ɛ, a resistor R and an inductor L. The circuit has a time constant τ. When another identical resistor R is connected in parallel to the first one, what is the new time constant?
A τ
B 2τ
C 4τ
D τ /2
E τ /4
Slide 15 / 25
15 A resistor R, an inductor L and a battery Ɛ are connected in series. Which of the following represents the Kirchhoff’s loop rule for the given circuit?
A
B
C
D
E
Slide 16 / 25
16 In the circuit above, initially the switch is open and then it is closed at time t =0. What is the current in the resistor at this time?
A 3 A
B 1 A
C 0
D 0.5 A
E 0.3 A
Slide 17 / 25
17 In the circuit above, the switch has been closed for a long time, then it is reopened at time t =0. Which of the following graphs best represents the electric current i as a function of time t?
A B
CD
E
Slide 18 / 25
18 In the circuit above, the switch is closed for a long time. What is the energy stored in the inductor?
A 3 J
B 6 J
C 18 J
D 24 J
E 36 J
Slide 19 / 25
19 An inductor of inductance of 2 H is connected in series to a resistor of 10 Ω and a 12 V battery. What is the time constant of the circuit?
A 5 s
B 10 s
C 0.2 s
D 0.1 s
E 0.6 s
Slide 20 / 25
20 An inductor of inductance of 0.4 H is connected in series to a resistor of 6 Ω and a 12 V battery. What is the energy stored in the inductor?
A 0.8 J
B 1.2 J
C 1.8 J
D 2.4 J
E 3.2 J
Slide 21 / 25
21 In the circuit above, at time t=0 the switch is placed in the position A. What is the current in the resistor at this time?
A 0.3 A
B 0.6 A
C 0
D 3 A
E 6 A
Slide 22 / 25
22 In the circuit above, at time t=0 the switch is placed in the position A. What is the voltage across the resistor at this time?
A 3 V
B 6 V
C 9 V
D 12 V
E 0
Slide 23 / 25
23 In the circuit above, the switch has been kept at the position A for a long time and then at time t=0 is placed at the position B. What is the current in the resistor at this time?
A 0.3 A
B 0.6 A
C 0
D 3 A
E 6 A
Slide 24 / 25
24 In the circuit above, a fully charged capacitor with a capacitance C = 25 µF and charge Q = 4 µC is connected to an inductor L = 10 mH? What is the current in the circuit at the instant when the switch is closed?
A 1 A
B 5 A
C 0
D 10 A
E 15 A
Slide 25 / 25
25 In the circuit above, a fully charged capacitor with a capacitance C = 25 µF and charge Q = 4 µC is connected to an inductor L = 10 mH? Which of the following occurs after the switch is closed?
A The charge instantaneously decreases to zero
B The charge expotentially decreases to zero
C The charge stays unchanged
D The charge oscillate with a period of π ms
E The charge oscillate with a period of π μs