JEE Main 2020 (Online) 6th September Morning Slot | Alternating Current Question 125 | Physics

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 :

$${L \over R}\ln \left( {{{\sqrt n } \over {\sqrt n + 1}}} \right)$$

$${L \over R}\ln \left( {{{\sqrt n } \over {\sqrt n - 1}}} \right)$$

$${L \over R}\ln \left( {{{\sqrt n + 1} \over {\sqrt n - 1}}} \right)$$

$${L \over R}\ln \left( {{{\sqrt n - 1} \over {\sqrt n }}} \right)$$

JEE Main 2020 (Online) 3rd September Morning Slot

MCQ (Single Correct Answer)

-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 10^oC. (assume no loss of heat to the surroudnings) is close to :

348 s

418 s

245 s

365 s

JEE Main 2020 (Online) 2nd September Evening Slot

MCQ (Single Correct Answer)

-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 45^o. The self-inductance of the coil is

6.7 $$ \times $$ 10^–7 H

1.1 $$ \times $$ 10^–1 H

5.5 $$ \times $$ 10^–5 H

1.1 $$ \times $$ 10^–2 H

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