1
JEE Main 2019 (Online) 10th January Morning Slot
+4
-1
If the magnetic field of a plane electromagnetic wave is given by (the speed of light = 3 × 108 B = 100 × 10–6 sin $$\left[ {2\pi \times 2 \times {{10}^{15}}\left( {t - {x \over c}} \right)} \right]$$ then the maximum electric field associated with it is -
A
4.5 $$\times$$ 104 N/C
B
4 $$\times$$ 104 N/C
C
6 $$\times$$ 104 N/C
D
3 $$\times$$ 104 N/C
2
JEE Main 2019 (Online) 9th January Evening Slot
+4
-1
A power transmission line feeds input power at 2300 V to a srep down transformer with its primary windings having 4000 turns. The output power is delivered at 230 V by the transformer. If the current in the primary of the transformer is 5A and its efficiency is 90%, the output current would be :
A
50 A
B
45 A
C
35 A
D
25 A
3
JEE Main 2019 (Online) 9th January Evening Slot
+4
-1
A series AC circuit containing an inductor (20 mH), a capacitor (120 $$\mu$$F) and a resistor (60 $$\Omega$$) is driven by an AC source of 24V/50 Hz. The energy dissipated in the circuit in 60 s is :
A
5.65 $$\times$$ 102J
B
2.26 $$\times$$ 103J
C
5.17 $$\times$$ 102 J
D
3.39 $$\times$$ 103 J
4
JEE Main 2018 (Online) 16th April Morning Slot
+4
-1
A coil of cross-sectional area A having n turns is placed in a uniform magnetic field B. When it is rotated with an angular velocity $$\omega ,$$ the maxium e.m.f. induced in the coil will be:
A
3 nBA$$\omega$$
B
$${3 \over 2}$$ nBA$$\omega$$
C
nBA$$\omega$$
D
$${1 \over 2}$$ nBA$$\omega$$
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