1
JEE Main 2021 (Online) 24th February Evening Slot
+4
-1
Figure shows a circuit that contains four identical resistors with resistance R = 2.0$$\Omega$$, two identical inductors with inductance L = 2.0 mH and an ideal battery with emf E = 9V. The current 'i' just after the switch 'S' is closed will be :

A
3.0 A
B
3.37 A
C
9 A
D
2.25 A
2
JEE Main 2020 (Online) 6th September Morning Slot
+4
-1
An AC circuit has R= 100 $$\Omega$$, C = 2 $$\mu$$F and L = 80 mH, connected in series. The quality factor of the circuit is :
A
20
B
2
C
0.5
D
400
3
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
$${L \over R}\ln \left( {{{\sqrt n - 1} \over {\sqrt n }}} \right)$$
4
JEE Main 2020 (Online) 4th September Morning Slot
+4
-1
Choose the correct option relating wave lengths of different parts of electromagnetic wave spectrum:
A
$$\lambda$$radio waves > $$\lambda$$micro waves > $$\lambda$$visible > $$\lambda$$x-rays
B
$$\lambda$$visible > $$\lambda$$x-rays > $$\lambda$$radio waves > $$\lambda$$micro waves
C
$$\lambda$$visible < $$\lambda$$micro waves < $$\lambda$$radio waves < $$\lambda$$x-rays
D
$$\lambda$$x-rays < $$\lambda$$micro waves < $$\lambda$$radio waves < $$\lambda$$visible
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