Video Lecture
Theory For Making Notes
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Practice Questions (Level-1)
Q.1
Two pure inductors, each of self inductance L are connected in parallel but are well separated from each other, then the total inductance is
(a) L
(b) 2L
(c) \frac{L}{2}
(d) \frac{L}{4}
Ans : (c)
Q.2
The current through an inductor of 1 H is given by
i = 3t sin t
The voltage across the inductor of 1 H is
(a) 3 sin t + 3 cos t
(b) 3 cos t + t sin t
(c) 3 sin t – 3t cos t
(d) 3t cos t + 3 sin t
Ans : (d)
Q.3
Dimensions of self-inductance are
(a) [MLT–2 A–2]
(b) [ML2T–1 A–2]
(c) [ML2T–2 A–2]
(d) [ML2T–2 A–1]
Ans : (c)
Q.4
The minimum value of inductance which can be obtained using three inductances of values 2H, 3H and 6H is
(a) 1H (b) 1/6H (c) 1/3H (d) 1H
Ans : (a)
Q.5
The inductance of a coil in which a current of 0.1 A increasing at the rate of 0.5 A/s represents a power flow of 0.5 W is
(a) 2 H (b) 8 H (c) 20 H (d) 10 H
Ans : (d)
Practice Questions (Level-2)
Q1
In the circuit shown in figure, A1 and A2 are ammeters, C is capacitance, L is the inductance, R1 and R2 are resistances and E is the emf. Just after key K is pressed, the reading is
(a) Maximum in both A1 and A2
(b) Zero in both A1 and A2
(c) Zero in A1 and maximum in A2
(d) Maximum in A1 and zero in A2
Ans. (d)
Q.2
In given figure two bulbs B1 and B2 and resistance R and an inductance L are connected in given circuit.
(a) Both B1 and B2 die out promptly
(b) Both B1 and B2 die out with same delay
(c) B2 dies out promptly but B1 with some delay
(d) B1 dies out promptly but B2 with some delay
Ans. (b)
Q.3
In the figure, a lamp P is in series with an iron-core inductor L. When the switch S is closed, the lamp brightness rises relatively slowly to its full brightness. This is due to
(a) the low resistance of P
(b) the low resistance of L
(c) the back emf in L
(d) the high voltage of the battery
Ans. (c)
Q.4
The time constant for the given circuit is
(a) 4 s
(b) \frac{1}{4}s
(c) 2 s
(d) \frac{1}{2}\,s
Ans. (b)
Q.5
The current i in an induction coil varies with time t according to the graph shown in the figure. Which of the following graphs shows the induced emf (E) in the coil with time
Ans. (c)
Q.6
When the number of turns in a coil is doubled without any change in the length of the coil, its self-inductance becomes
(a) four times
(b) doubled
(c) halved
(d) squared
Ans. (b)
Q.7
A uniformly wound long solenoid of inductance L and resistance R is broken into two equal parts, which are then joined in parallel. This combination is then joined to a cell of emf e. The time constant of the circuit is
(a) L/R (b) L/2R (c) 2 L/R (d) L/4R
Ans. (a)
Q.8
When a coil carrying a steady current is short-circuited, the current in it decrease h times in time t0. The time constant of the circuit is
(a) {{t}_{0}}1\text{n}\,\eta
(b) \frac{{{{t}_{0}}}}{{\ln \ \eta }}
(c) \frac{{{{t}_{0}}}}{\eta }
(d) \frac{{{{t}_{0}}}}{{\eta -1}}
Ans. (b)