JEE Main 2018 (Online) 16th April Morning Slot | Magnetics Question 212 | Physics

JEE Main 2018 (Online) 16th April Morning Slot

MCQ (Single Correct Answer)

-1

A galvanometer with its coil resistance 25 $$\Omega $$ requires a current of 1 mA for its full deflection. In order to construct an ammeter to read upto a current of 2 A, the approximate value of the shunt resistance should be :

$$2.5 \times {10^{ - 3}}\,\Omega $$

$$1.25 \times {10^{ - 2}}\Omega $$

$$1.25 \times {10^{ - 3}}\Omega $$

$$2.5 \times {10^{ - 2}}\Omega $$

JEE Main 2018 (Online) 16th April Morning Slot

MCQ (Single Correct Answer)

-1

A charge q is spread uniformly over an insulated loop of radius r. If it is rotated with an angular velocity $$\omega $$ with resect to normal axis then the magnetic moment of the loop is :

q $$\omega $$r²

$${4 \over 3}$$ q $$\omega $$r²

$${3 \over 2}$$ q $$\omega $$r²

$${1 \over 2}$$ q $$\omega $$r²

JEE Main 2018 (Offline)

MCQ (Single Correct Answer)

-1

An electron, a proton and an alpha particle having the same kinetic energy are moving in circular orbits of radii r_e, r_p, r$$_\alpha$$ respectively in a uniform magnetic field B. The relation between r_e, r_p, r$$_\alpha$$ is:

r_e < r$$_\alpha$$ < r_p

r_e > r_p = r$$_\alpha$$

r_e < r_p = r$$_\alpha$$

r_e < r_p < r$$_\alpha$$

JEE Main 2018 (Offline)

MCQ (Single Correct Answer)

-1

The dipole moment of a circular loop carrying a current I, is m and the magnetic field at the centre of the loop is B₁. When the dipole moment is doubled by keeping the current constant, the magnetic field at the centre of the loop is $${{B_2}}$$. The ratio $${{{B_1}} \over {{B_2}}}$$ is:

$$\sqrt 3 $$

$$\sqrt 2 $$

$$1 \over \sqrt 2 $$

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