1
JEE Main 2019 (Online) 9th April Evening Slot
+4
-1
A very long solenoid of radius R is carrying current I(t) = kte–at(k > 0), as a function of time (t $$\ge$$ 0). counter clockwise current is taken to be positive. A circular conducting coil of radius 2R is placed in the equatorial plane of the solenoid and concentric with the solenoid. The current induced in the outer coil is correctly depicted, as a function of time, by :-
A
B
C
D
2
JEE Main 2019 (Online) 9th April Morning Slot
+4
-1
The total number of turns and cross-section area in a solenoid is fixed. However, its length L is varied by adjusting the separation between windings. The inductance of solenoid will be proportional to :
A
1/L2
B
1/L
C
L
D
L2
3
JEE Main 2019 (Online) 8th April Evening Slot
+4
-1
A circuit connected to an ac source of emf e = e0sin(100t) with t in seconds, gives a phase difference of $$\pi$$/4 between the emf e and current i. Which of the following circuits will exhibit this ?
A
RC circuit with R = 1 k$$\Omega$$ and C = 1μF
B
RL circuit with R = 1k$$\Omega$$ and L = 1mH
C
RC circuit with R = 1k$$\Omega$$ and C = 10 μF
D
RL circuit with R = 1 k$$\Omega$$ and L = 10 mH
4
JEE Main 2019 (Online) 8th April Morning Slot
+4
-1
A 20 Henry inductor coil is connected to a 10 ohm resistance in series as shown in figure. The time at which rate of dissipation of energy (joule's heat) across resistance is equal to the rate at which magnetic energy is stored in the inductor is :
A
$${2 \over {\ln 2}}$$
B
$${\ln 2}$$
C
$$2{\ln 2}$$
D
$${1 \over 2}{\ln 2}$$
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