1
JEE Main 2020 (Online) 5th September Morning Slot
+4
-1
An electron is constrained to move along the y-axis with a speed of 0.1 c (c is the speed of light) in the presence of electromagnetic wave, whose electric field is
$$\overrightarrow E = 30\widehat j\sin \left( {1.5 \times {{10}^7}t - 5 \times {{10}^{ - 2}}x} \right)$$ V/m.
The maximum magnetic force experienced by the electron will be :
(given c = 3 $$\times$$ 108 ms–1 and electron charge = 1.6 $$\times$$ 10–19 C)
A
4.8 $$\times$$ 10–19 N
B
2.4 $$\times$$ 10–18 N
C
3.2 $$\times$$ 10–18 N
D
1.6 $$\times$$ 10–18 N
2
JEE Main 2020 (Online) 4th September Evening Slot
+4
-1
The electric field of a plane electromagnetic wave is given by
$$\overrightarrow E = {E_0}\left( {\widehat x + \widehat y} \right)\sin \left( {kz - \omega t} \right)$$
Its magnetic field will be given by :
A
$${{{E_0}} \over c}\left( {\widehat x + \widehat y} \right)\sin \left( {kz - \omega t} \right)$$
B
$${{{E_0}} \over c}\left( {\widehat x - \widehat y} \right)\sin \left( {kz - \omega t} \right)$$
C
$${{{E_0}} \over c}\left( {\widehat x - \widehat y} \right)\cos \left( {kz - \omega t} \right)$$
D
$${{{E_0}} \over c}\left( { - \widehat x + \widehat y} \right)\sin \left( {kz - \omega t} \right)$$
3
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
4
JEE Main 2020 (Online) 3rd September Evening Slot
+4
-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 :
A
$$\overrightarrow B = {{{E_0}} \over {\sqrt {{\mu _0}{ \in _0}} }}\cos \left( {kx} \right)\widehat j$$
B
$$\overrightarrow B = {{{E_0}} \over {\sqrt {{\mu _0}{ \in _0}} }}\cos \left( {kx} \right)\widehat k$$
C
$$\overrightarrow B = {E_0}\sqrt {{\mu _0}{ \in _0}} \cos \left( {kx} \right)\widehat k$$
D
$$\overrightarrow B = {E_0}\sqrt {{\mu _0}{ \in _0}} \cos \left( {kx} \right)\widehat j$$
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