1
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
2
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
3
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
$${1 \over 2}{\ln 2}$$
4
JEE Main 2019 (Online) 8th April Morning Slot
+4
-1
An alternating voltage v(t) = 220 sin 100 $$\pi$$t volt is applied to a purely resistance load of 50$$\Omega$$ . The time taken for the current to rise from half of the peak value to the peak value is :
A
5 ms
B
2.2 ms
C
3.3 ms
D
7.2 ms
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