1
JEE Main 2022 (Online) 26th July Morning Shift
+4
-1 The magnetic field of a plane electromagnetic wave is given by :

$$\overrightarrow{\mathrm{B}}=2 \times 10^{-8} \sin \left(0.5 \times 10^{3} x+1.5 \times 10^{11} \mathrm{t}\right) \,\hat{j} \mathrm{~T}$$.

The amplitude of the electric field would be :

A
$$6\, \mathrm{Vm}^{-1}$$ along $$x$$-axis
B
$$3\, \mathrm{Vm}^{-1}$$ along $$z$$-axis
C
$$6\, \mathrm{Vm}^{-1}$$ along $$z$$-axis
D
$$2 \times 10^{-8} \,\mathrm{Vm}^{-1}$$ along $$z$$-axis
2
JEE Main 2022 (Online) 26th July Morning Shift
+4
-1 In a series $$L R$$ circuit $$X_{L}=R$$ and power factor of the circuit is $$P_{1}$$. When capacitor with capacitance $$C$$ such that $$X_{L}=X_{C}$$ is put in series, the power factor becomes $$P_{2}$$. The ratio $$\frac{P_{1}}{P_{2}}$$ is:

A
$$\frac{1}{2}$$
B
$$\frac{1}{\sqrt{2}}$$
C
$$\frac{\sqrt{3}}{\sqrt{2}}$$
D
2 : 1
3
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
$${25 \over 2}$$
4
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
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