1
JEE Main 2020 (Online) 8th January Evening Slot
+4
-1
A plane electromagnetic wave of frequency 25 GHz is propagating in vacuum along the z-direction. At a particular point in space and time, the magnetic field is given by $$\overrightarrow B = 5 \times {10^{ - 8}}\widehat jT$$. The corresponding electric field $$\overrightarrow E$$ is (speed of light c = 3 × 108 ms–1)
A
15 $$\widehat i$$V / m
B
-15 $$\widehat i$$V / m
C
1.66 × 10–16 $$\widehat i$$V / m
D
-1.66 × 10–16 $$\widehat i$$V / m
2
JEE Main 2020 (Online) 8th January Evening Slot
+4
-1
A very long wire ABDMNDC is shown in figure carrying current I. AB and BC parts are straight, long and at right angle. At D wire forms a circular turn DMND of radius R. AB, BC parts are tangential to circular turn at N and D. Magnetic field at the centre of circle is :
A
$${{{\mu _0}I} \over {2\pi R}}\left( {\pi + 1} \right)$$
B
$${{{\mu _0}I} \over {2\pi R}}\left( {\pi - {1 \over {\sqrt 2 }}} \right)$$
C
$${{{\mu _0}I} \over {2R}}$$
D
$${{{\mu _0}I} \over {2\pi R}}\left( {\pi + {1 \over {\sqrt 2 }}} \right)$$
3
JEE Main 2020 (Online) 8th January Morning Slot
+4
-1
Photon with kinetic energy of 1MeV moves from south to north. It gets an acceleration of 1012 m/s2 by an applied magnetic field (west to east). The value of magnetic field : (Rest mass of proton is 1.6 × 10–27 kg) :
A
0.71mT
B
7.1mT
C
0.071mT
D
71mT
4
JEE Main 2020 (Online) 8th January Morning Slot
+4
-1
At time t = 0 magnetic field of 1000 Gauss is passing perpendicularly through the area defined by the closed loop shown in the figure. If the magnetic field reduces linearly to 500 Gauss, in the next 5s, then induced EMF in the loop is :
A
48 μV
B
28 μV
C
56 μV
D
36 μV
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