1
JEE Main 2019 (Online) 11th January Evening Slot
+4
-1
A paramagnetic substance in the form of a cube with sides 1 cm has a magnetic dipole moment of 20 $$\times$$ 10–6 J/ T when a magnetic intensity of 60 $$\times$$ 103 A/m is applied. Its magnetic susceptibility is
A
3.3 $$\times$$ 10–4
B
2.3 $$\times$$ 10–2
C
4.3 $$\times$$ 10–2
D
3.3 $$\times$$ 10–2
2
JEE Main 2019 (Online) 11th January Evening Slot
+4
-1
A 27 mW laser beam has a cross-sectional area of 10 mm2. The magnitude of the maximum electric field in this electromagnetic wave is given by :
[Given permittivity of space $$\in$$0 = 9 $$\times$$ 10–12 SI units, Speed of light c = 3 $$\times$$ 108 m/s]
A
2 kV/m
B
1 kV/m
C
1.4 kV/m
D
0.7 kV/m
3
JEE Main 2019 (Online) 11th January Morning Slot
+4
-1
An electromagnetic wave of intensity 50 Wm–2 enters in a medium of refractive index 'n' without any loss. The ratio of the magnitudes of electric, and the ratio of the magnitudes of magnetic fields of the wave before and after entering into the medium are respectively, given by:
A
$$\left( {{1 \over {\sqrt n }},{1 \over {\sqrt n }}} \right)$$
B
$$\left( {\sqrt n ,\sqrt n } \right)$$
C
$$\left( {\sqrt n ,{1 \over {\sqrt n }}} \right)$$
D
$$\left( {{1 \over {\sqrt n }},\sqrt n } \right)$$
4
JEE Main 2019 (Online) 10th January Evening Slot
+4
-1
The self induced emf of a coil is 25 volts. When the current in it is changed at uniform rate from 10 A to 25 A in 1s, the change in the energy of the inductance is -
A
740 J
B
637.5 J
C
540 J
D
437.5 J
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