1
JEE Main 2022 (Online) 27th July Evening Shift
+4
-1
Out of Syllabus

A compass needle of oscillation magnetometer oscillates 20 times per minute at a place $$\mathrm{P}$$ of $$\operatorname{dip} 30^{\circ}$$. The number of oscillations per minute become 10 at another place $$\mathrm{Q}$$ of $$60^{\circ}$$ dip. The ratio of the total magnetic field at the two places $$\left(B_{Q}: B_{P}\right)$$ is :

A
$$\sqrt{3}: 4$$
B
$$4: \sqrt{3}$$
C
$$\sqrt{3}: 2$$
D
$$2: \sqrt{3}$$
2
JEE Main 2022 (Online) 27th July Morning Shift
+4
-1
Out of Syllabus

Two bar magnets oscillate in a horizontal plane in earth's magnetic field with time periods of $$3 \mathrm{~s}$$ and $$4 \mathrm{~s}$$ respectively. If their moments of inertia are in the ratio of $$3: 2$$, then the ratio of their magnetic moments will be:

A
2 : 1
B
8 : 3
C
1 : 3
D
27 : 16
3
JEE Main 2022 (Online) 27th July Morning Shift
+4
-1
Out of Syllabus

A magnet hung at $$45^{\circ}$$ with magnetic meridian makes an angle of $$60^{\circ}$$ with the horizontal. The actual value of the angle of dip is -

A
$$\tan ^{-1}\left(\sqrt{\frac{3}{2}}\right)$$
B
$$\tan ^{-1}(\sqrt{6})$$
C
$$\tan ^{-1}\left(\sqrt{\frac{2}{3}}\right)$$
D
$$\tan ^{-1}\left(\sqrt{\frac{1}{2}}\right)$$
4
JEE Main 2022 (Online) 25th July Evening Shift
+4
-1
Out of Syllabus

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)

A
$$1.6 \times 10^{5} \mathrm{~Hz}$$
B
$$5.6 \times 10^{5} \mathrm{~Hz}$$
C
$$2.8 \times 10^{6} \mathrm{~Hz}$$
D
$$1.8 \times 10^{6} \mathrm{~Hz}$$
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