JEE Main 2020 (Online) 6th September Morning Slot | Alternating Current and Electromagnetic Induction Question 134 | Physics

JEE Main 2020 (Online) 6th September Morning Slot

MCQ (Single Correct Answer)

-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 :

0.5

400

JEE Main 2020 (Online) 4th September Evening Slot

MCQ (Single Correct Answer)

-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 :

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

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

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

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

JEE Main 2020 (Online) 4th September Morning Slot

MCQ (Single Correct Answer)

-1

Choose the correct option relating wave lengths of different parts of electromagnetic wave spectrum:

$$\lambda $$_{radio waves} > $$\lambda $$_{micro waves} > $$\lambda $$_visible > $$\lambda $$_x-rays

$$\lambda $$_visible > $$\lambda $$_x-rays > $$\lambda $$_{radio waves} > $$\lambda $$_{micro waves}

$$\lambda $$_visible < $$\lambda $$_{micro waves} < $$\lambda $$_{radio waves} < $$\lambda $$_x-rays

$$\lambda $$_x-rays < $$\lambda $$_{micro waves} < $$\lambda $$_{radio waves} < $$\lambda $$_visible

JEE Main 2020 (Online) 3rd September Evening Slot

MCQ (Single Correct Answer)

-1

The electric field of a plane electromagnetic wave propagating along the x direction in vacuum is
$$\overrightarrow E = {E_0}\widehat j\cos \left( {\omega t - kx} \right)$$.
The magnetic field $$\overrightarrow B $$ , at the moment t = 0 is :

$$\overrightarrow B = {{{E_0}} \over {\sqrt {{\mu _0}{ \in _0}} }}\cos \left( {kx} \right)\widehat j$$

$$\overrightarrow B = {{{E_0}} \over {\sqrt {{\mu _0}{ \in _0}} }}\cos \left( {kx} \right)\widehat k$$

$$\overrightarrow B = {E_0}\sqrt {{\mu _0}{ \in _0}} \cos \left( {kx} \right)\widehat k$$

$$\overrightarrow B = {E_0}\sqrt {{\mu _0}{ \in _0}} \cos \left( {kx} \right)\widehat j$$

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