1
JEE Main 2022 (Online) 25th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The rms value of conduction current in a parallel plate capacitor is $$6.9 \,\mu \mathrm{A}$$. The capacity of this capacitor, if it is connected to $$230 \mathrm{~V}$$ ac supply with an angular frequency of $$600 \,\mathrm{rad} / \mathrm{s}$$, will be :

A
5 pF
B
50 pF
C
100 pF
D
200 pF
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) 28th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

An EM wave propagating in x-direction has a wavelength of 8 mm. The electric field vibrating y-direction has maximum magnitude of 60 Vm$$-$$1. Choose the correct equations for electric and magnetic fields if the EM wave is propagating in vacuum :

A

$${E_y} = 60\sin \left[ {{\pi \over 4} \times {{10}^3}(x - 3 \times {{10}^8}t)} \right]\widehat j\,\,V{m^{ - 1}}$$

$${B_z} = 2\sin \left[ {{\pi \over 4} \times {{10}^3}(x - 3 \times {{10}^8}t)} \right]\widehat k\,\,T$$

B

$${E_y} = 60\sin \left[ {{\pi \over 4} \times {{10}^3}(x - 3 \times {{10}^8}t)} \right]\widehat j\,\,V{m^{ - 1}}$$

$${B_z} = 2 \times {10^{ - 7}}\sin \left[ {{\pi \over 4} \times {{10}^3}(x - 3 \times {{10}^8}t)} \right]\widehat k\,\,T$$

C

$${E_y} = 2 \times {10^{ - 7}}\sin \left[ {{\pi \over 4} \times {{10}^3}(x - 3 \times {{10}^8}t)} \right]\widehat j\,\,V{m^{ - 1}}$$

$${B_z} = 60\sin \left[ {{\pi \over 4} \times {{10}^3}(x - 3 \times {{10}^8}t)} \right]\widehat k\,\,T$$

D

$${E_y} = 2 \times {10^{ - 7}}\sin \left[ {{\pi \over 4} \times {{10}^4}(x - 4 \times {{10}^8}t)} \right]\widehat j\,\,V{m^{ - 1}}$$

$${B_z} = 60\sin \left[ {{\pi \over 4} \times {{10}^4}(x - 4 \times {{10}^8}t)} \right]\widehat k\,\,T$$

4
JEE Main 2022 (Online) 28th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A radar sends an electromagnetic signal of electric field (E0) = 2.25 V/m and magnetic field (B0) = 1.5 $$\times$$ 10$$-$$8 T which strikes a target on line of sight at a distance of 3 km in a medium. After that, a part of signal (echo) reflects back towards the radar with same velocity and by same path. If the signal was transmitted at time t = 0 from radar, then after how much time echo will reach to the radar?

A
2.0 $$\times$$ 10$$-$$5 s
B
4.0 $$\times$$ 10$$-$$5 s
C
1.0 $$\times$$ 10$$-$$5 s
D
8.0 $$\times$$ 10$$-$$5 s
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