1
JEE Main 2022 (Online) 25th July Evening Shift
+4
-1

The electric current in a circular coil of 2 turns produces a magnetic induction B1 at its centre. The coil is unwound and in rewound into a circular coil of 5 tuns and the same current produces a magnetic induction B2 at its centre. The ratio of $${{{B_2}} \over {{B_1}}}$$ is

A
$${5 \over 2}$$
B
$${25 \over 4}$$
C
$${5 \over 4}$$
D
$${25 \over 2}$$
2
JEE Main 2022 (Online) 25th July Evening Shift
+4
-1

Light wave travelling in air along x-direction is given by $${E_y} = 540\sin \pi \times {10^4}(x - ct)\,V{m^{ - 1}}$$. Then, the peak value of magnetic field of wave will be (Given c = 3 $$\times$$ 108 ms$$-$$1)

A
18 $$\times$$ 10$$-$$7 T
B
54 $$\times$$ 10$$-$$7 T
C
54 $$\times$$ 10$$-$$8 T
D
18 $$\times$$ 10$$-$$8 T
3
JEE Main 2022 (Online) 25th July Evening Shift
+4
-1

When you walk through a metal detector carrying a metal object in your pocket, it raises an alarm. This phenomenon works on :

A
Electromagnetic induction
B
Resonance in ac circuits
C
Mutual induction in ac circuits
D
Interference of electromagnetic waves
4
JEE Main 2022 (Online) 25th July Morning Shift
+4
-1

To increase the resonant frequency in series LCR circuit,

A
source frequency should be increased.
B
another resistance should be added in series with the first resistance.
C
another capacitor should be added in series with the first capacitor.
D
the source frequency should be decreased.
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Physics
Mechanics
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Optics
Modern Physics
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