1
JEE Main 2021 (Online) 25th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Magnetic fields at two points on the axis of a circular coil at a distance of 0.05 m and 0.2 m from the centre are in the ratio 8 : 1. The radius of coil is ________.
A
1.0 m
B
0.15 m
C
0.2 m
D
0.1 m
2
JEE Main 2020 (Online) 6th September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A charged particle going around in a circle can be considered to be a current loop. A particle of mass m carrying charge q is moving in a plane with speed v under the influence of magnetic field $$\overrightarrow B $$. The magnetic moment of this moving particle:
A
$${{m{v^2}\overrightarrow B } \over {2{B^2}}}$$
B
-$${{m{v^2}\overrightarrow B } \over {2{B^2}}}$$
C
-$${{m{v^2}\overrightarrow B } \over {{B^2}}}$$
D
-$${{m{v^2}\overrightarrow B } \over {2\pi {B^2}}}$$
3
JEE Main 2020 (Online) 6th September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A square loop of side 2$$a$$ and carrying current I is kept in xz plane with its centre at origin. A long wire carrying the same current I is placed parallel to z-axis and passing through point (0, b, 0), (b >> a). The magnitude of torque on the loop about z-axis will be :
A
$${{2{\mu _0}{I^2}{a^2}} \over {\pi b}}$$
B
$${{2{\mu _0}{I^2}{a^2}b} \over {\pi \left( {{a^2} + {b^2}} \right)}}$$
C
$${{{\mu _0}{I^2}{a^2}b} \over {2\pi \left( {{a^2} + {b^2}} \right)}}$$
D
$${{{\mu _0}{I^2}{a^2}} \over {2\pi b}}$$
4
JEE Main 2020 (Online) 6th September Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A particle of charge q and mass m is moving with a velocity $$ - v\widehat i$$ (v $$ \ne $$ 0) towards a large screen placed in the Y - Z plane at a distance d. If there is a magnetic field $$\overrightarrow B = {B_0}\widehat k$$ , the maximum value of v for which the particle will not hit the screen is :
A
$${{2qd{B_0}} \over m}$$
B
$${{qd{B_0}} \over {3m}}$$
C
$${{qd{B_0}} \over {2m}}$$
D
$${{qd{B_0}} \over {m}}$$
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