JEE Main 2022 (Online) 25th July Evening Shift | Magnetics Question 42 | Physics

JEE Main 2022 (Online) 25th July Evening Shift

MCQ (Single Correct Answer)

-1

An electron with energy 0.1 keV moves at right angle to the earth's magnetic field of 1 $$\times$$ 10^$$-$$4 Wbm^$$-$$2. The frequency of revolution of the electron will be

(Take mass of electron = 9.0 $$\times$$ 10^$$-$$31 kg)

$$1.6 \times 10^{5} \mathrm{~Hz}$$

$$5.6 \times 10^{5} \mathrm{~Hz}$$

$$2.8 \times 10^{6} \mathrm{~Hz}$$

$$1.8 \times 10^{6} \mathrm{~Hz}$$

JEE Main 2022 (Online) 25th July Morning Shift

MCQ (Single Correct Answer)

-1

Two charged particles, having same kinetic energy, are allowed to pass through a uniform magnetic field perpendicular to the direction of motion. If the ratio of radii of their circular paths is $$6: 5$$ and their respective masses ratio is $$9: 4$$. Then, the ratio of their charges will be :

8 : 5

5 : 4

5 : 3

8 : 7

JEE Main 2022 (Online) 25th July Morning Shift

MCQ (Single Correct Answer)

-1

The magnetic moment of an electron (e) revolving in an orbit around nucleus with an orbital angular momentum is given by :

$$ \vec{\mu}_{\mathrm{L}}=\frac{\overrightarrow{\mathrm{eL}}}{2 \mathrm{~m}} $$

$$\vec{\mu}_{\mathrm{L}}=-\frac{\overrightarrow{\mathrm{eL}}}{2 \mathrm{~m}}$$

$$\vec{\mu}_{l}=-\frac{\overrightarrow{e L}}{\mathrm{~m}}$$

$$ \vec{\mu}_{l}=\frac{2 \overrightarrow{\mathrm{eL}}}{\mathrm{m}} $$

JEE Main 2022 (Online) 30th June Morning Shift

MCQ (Single Correct Answer)

-1

A coil of n number of turns wound tightly in the form of a spiral with inner and outer radii r₁ and r₂ respectively. When a current of strength I is passed through the coil, the magnetic field at its centre will be :

$${{{\mu _0}nI} \over {2({r_2} - {r_1})}}$$

$${{{\mu _0}nI} \over {{r_2}}}$$

$${{{\mu _0}nI} \over {{r_2} - {r_1}}}{\log _e}{{{r_1}} \over {{r_2}}}$$

$${{{\mu _0}nI} \over {2({r_2} - {r_1})}}{\log _e}{{{r_2}} \over {{r_1}}}$$

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