JEE Main 2020 (Online) 2nd September Evening Slot | Alternating Current and Electromagnetic Induction Question 141 | Physics

JEE Main 2020 (Online) 2nd September Evening Slot

MCQ (Single Correct Answer)

-1

In a plane electromagnetic wave, the directions of electric field and magnetic field are represented by $$\widehat k$$ and $$2\widehat i - 2\widehat j$$, respectively. What is the unit vector along direction of propagation of the wave?

$${1 \over {\sqrt 5 }}\left( {\widehat i + 2\widehat j} \right)$$

$${1 \over {\sqrt 5 }}\left( {2\widehat i + \widehat j} \right)$$

$${1 \over {\sqrt 2 }}\left( {\widehat i + \widehat j} \right)$$

$${1 \over {\sqrt 2 }}\left( {\widehat j + \widehat k} \right)$$

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

JEE Main 2020 (Online) 2nd September Morning Slot

MCQ (Single Correct Answer)

-1

A plane electromagnetic wave, has
frequency of 2.0 $$ \times $$ 10¹⁰ Hz and its energy density is 1.02 $$ \times $$ 10^–8 J/m³ in vacuum. The amplitude of the magnetic field of the wave is close to
( $${1 \over {4\pi {\varepsilon _0}}} = 9 \times {10^9}{{N{m^2}} \over {{C^2}}}$$ and speed of light
= 3 $$ \times $$ 10⁸ ms^–1)

190 nT

150 nT

160 nT

180 nT

JEE Main 2020 (Online) 9th January Evening Slot

MCQ (Single Correct Answer)

-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 :

0.52 cos 314 t

5.2 cos 314 t

0.52 sin 314 t

10 cos 314 t

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