JEE Main 2021 (Online) 25th February Morning Shift | Magnetics Question 123 | Physics

JEE Main 2021 (Online) 25th February Morning Shift

MCQ (Single Correct Answer)

-1

A proton, a deuteron and an $$\alpha$$ particle are moving with same momentum in a uniform magnetic field. The ratio of magnetic forces acting on them is _________ and their speed is _______, in the ratio.

2 : 1 : 1 and 4 : 2 : 1

4 : 2 : 1 and 2 : 1 : 1

1 : 2 : 4 and 2 : 1 : 1

1 : 2 : 4 and 1 : 1 : 2

JEE Main 2021 (Online) 25th February Morning Shift

MCQ (Single Correct Answer)

-1

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 ________.

1.0 m

0.15 m

0.2 m

0.1 m

JEE Main 2021 (Online) 24th February Evening Shift

MCQ (Single Correct Answer)

-1

A soft ferromagnetic material is placed in an external magnetic field. The magnetic domains :

may increase or decrease in size and change its orientation.

increase in size but no change in orientation.

decrease in size and changes orientation.

have no relation with external magnetic field.

JEE Main 2020 (Online) 6th September Evening Slot

MCQ (Single Correct Answer)

-1

For a plane electromagnetic wave, the magnetic field at a point x and time t is

$$\overrightarrow B \left( {x,t} \right)$$ = $$\left[ {1.2 \times {{10}^{ - 7}}\sin \left( {0.5 \times {{10}^3}x + 1.5 \times {{10}^{11}}t} \right)\widehat k} \right]$$ T

The instantaneous electric field $$\overrightarrow E $$ corresponding to $$\overrightarrow B $$ is :
(speed of light c = 3 × 10⁸ ms^–1)

$$\overrightarrow E \left( {x,t} \right) = \left[ {36\sin \left( {1 \times {{10}^3}x + 1.5 \times {{10}^{11}}t} \right)\widehat i} \right]$$ $${V \over m}$$

$$\overrightarrow E \left( {x,t} \right) = \left[ {36\sin \left( {0.5 \times {{10}^3}x + 1.5 \times {{10}^{11}}t} \right)\widehat k} \right]{V \over m}$$

$$\overrightarrow E \left( {x,t} \right) = \left[ {36\sin \left( {1 \times {{10}^3}x + 0.5 \times {{10}^{11}}t} \right)\widehat j} \right]{V \over m}$$

$$\overrightarrow E \left( {x,t} \right) = \left[ { - 36\sin \left( {0.5 \times {{10}^3}x + 1.5 \times {{10}^{11}}t} \right)\widehat j} \right]{V \over m}$$

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