1
JEE Main 2020 (Online) 4th September Evening Slot
+4
-1
A series L-R circuit is connected to a battery of emf V. If the circuit is switched on at t = 0, then the time at which the energy stored in the inductor reaches $$\left( {{1 \over n}} \right)$$ times of its maximum value, is :
A
$${L \over R}\ln \left( {{{\sqrt n } \over {\sqrt n + 1}}} \right)$$
B
$${L \over R}\ln \left( {{{\sqrt n } \over {\sqrt n - 1}}} \right)$$
C
$${L \over R}\ln \left( {{{\sqrt n + 1} \over {\sqrt n - 1}}} \right)$$
D
$${L \over R}\ln \left( {{{\sqrt n - 1} \over {\sqrt n }}} \right)$$
2
JEE Main 2020 (Online) 3rd September Morning Slot
+4
-1
A 750 Hz, 20 V (rms) source is connected to a resistance of 100 $$\Omega$$, an inductance of 0.1803 H and a capacitance of 10 $$\mu$$F all in series. The time in which the resistance (heat capacity 2 J/oC) will get heated by 10oC. (assume no loss of heat to the surroudnings) is close to :
A
348 s
B
418 s
C
245 s
D
365 s
3
JEE Main 2020 (Online) 2nd September Evening Slot
+4
-1
An inductance coil has a reactance of 100 $$\Omega$$. When an AC signal of frequency 1000 Hz is applied to the coil, the applied voltage leads the current by 45o. The self-inductance of the coil is
A
6.7 $$\times$$ 10–7 H
B
1.1 $$\times$$ 10–1 H
C
5.5 $$\times$$ 10–5 H
D
1.1 $$\times$$ 10–2 H
4
JEE Main 2020 (Online) 9th January Evening Slot
+4
-1
In LC circuit the inductance L = 40 mH and
capacitance C = 100 $$\mu$$F. If a voltage
V(t) = 10sin(314t) is applied to the circuit, the
current in the circuit is given as :
A
0.52 cos 314 t
B
5.2 cos 314 t
C
0.52 sin 314 t
D
10 cos 314 t
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