1
JEE Main 2022 (Online) 30th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Which of the following equations correctly represents a travelling wave having wavelength $$\lambda$$ = 4.0 cm, frequency v = 100 Hz and travelling in positive x-axis direction?

A
$$y = A\sin [(0.50\,\pi \,c{m^{ - 1}})x - (100\,\pi \,{s^{ - 1}})t]$$
B
$$y = A\sin \,\,2\pi [(0.25\,\,c{m^{ - 1}})x - (50\,{s^{ - 1}})t]$$
C
$$y = A\sin \left[ {\left( {{{2\pi } \over 4}\,c{m^{ - 1}}} \right)x - \left( {{{2\pi } \over {100}}\,{s^{ - 1}}} \right)t} \right]$$
D
$$y = A\sin \,\pi [(0.5\,\,c{m^{ - 1}})x - (200\,\,{s^{ - 1}})t]$$
2
JEE Main 2022 (Online) 30th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

An expression for oscillating electric field in a plane electromagnetic wave is given as Ez = 300 sin(5$$\pi$$ $$\times$$ 103x $$-$$ 3$$\pi$$ $$\times$$ 1011t) Vm$$-$$1

Then, the value of magnetic field amplitude will be :

(Given : speed of light in Vacuum c = 3 $$\times$$ 108 ms$$-$$1)

A
1 $$\times$$ 10$$-$$6 T
B
5 $$\times$$ 10$$-$$6 T
C
18 $$\times$$ 109 T
D
21 $$\times$$ 109 T
3
JEE Main 2022 (Online) 30th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

An electric cable of copper has just one wire of radius 9 mm. Its resistance is 14 $$\Omega$$. If this single copper wire of the cable is replaced by seven identical well insulated copper wires each of radius 3 mm connected in parallel, then the new resistance of the combination will be :

A
9 $$\Omega$$
B
18 $$\Omega$$
C
28 $$\Omega$$
D
126 $$\Omega$$
4
JEE Main 2022 (Online) 30th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

In series RLC resonator, if the self inductance and capacitance become double, the new resonant frequency (f2) and new quality factor (Q2) will be :

(f1 = original resonant frequency, Q1 = original quality factor)

A
$${f_2} = {{{f_1}} \over 2}$$ and $${Q_2} = {Q_1}$$
B
$${f_2} = {f_1}$$ and $${Q_2} = {{{Q_1}} \over {{Q_2}}}$$
C
$${f_2} = 2{f_1}$$ and $${Q_2} = {Q_1}$$
D
$${f_2} = {f_1}$$ and $${Q_2} = 2{Q_1}$$
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