JEE Main 2022 (Online) 25th June Morning Shift | Magnetics Question 65 | Physics

JEE Main 2022 (Online) 25th June Morning Shift

MCQ (Single Correct Answer)

-1

A long straight wire with a circular cross-section having radius R, is carrying a steady current I. The current I is uniformly distributed across this cross-section. Then the variation of magnetic field due to current I with distance r (r < R) from its centre will be :

B $$\propto$$ r²

B $$\propto$$ r

B $$\propto$$ $${1 \over {{r^2}}}$$

B $$\propto$$ $${1 \over {{r}}}$$

JEE Main 2022 (Online) 24th June Evening Shift

MCQ (Single Correct Answer)

-1

The soft-iron is a suitable material for making an electromagnet. This is because soft-iron has

low coercivity and high retentivity.

low coercivity and low permeability.

high permeability and low retentivity.

high permeability and high retentivity.

JEE Main 2022 (Online) 24th June Evening Shift

MCQ (Single Correct Answer)

-1

A proton, a deutron and an $$\alpha$$-particle with same kinetic energy enter into a uniform magnetic field at right angle to magnetic field. The ratio of the radii of their respective circular paths is :

1 : $$\sqrt 2 $$ : $$\sqrt 2 $$

1 : 1 : $$\sqrt 2 $$

$$\sqrt 2 $$ : 1 : 1

1 : $$\sqrt 2 $$ : 1

JEE Main 2022 (Online) 24th June Evening Shift

MCQ (Single Correct Answer)

-1

An electric bulb is rated as 200 W. What will be the peak magnetic field at 4 m distance produced by the radiations coming from this bulb? Consider this bulb as a point source with 3.5% efficiency.

1.19 $$\times$$ 10^$$-$$8T

1.71 $$\times$$ 10^$$-$$8T

0.84 $$\times$$ 10^$$-$$8T

3.36 $$\times$$ 10^$$-$$8T

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