JEE Main 2019 (Online) 12th January Evening Slot | Electromagnetic Induction Question 91 | Physics

A 10 m long horizontal wire extends from North East to South West. It is falling with a speed of 5.0 ms^–1, at right angles to the horizontal component of the earth's magnetic field of 0.3 $$ \times $$ 10^–4 Wb/m². The value of the induced emf in wire is :

0.3 $$ \times $$ 10^–3 V

2.5 $$ \times $$ 10^–3 V

1.5 $$ \times $$ 10^–3 V

1.1 $$ \times $$ 10^–3 V

JEE Main 2019 (Online) 11th January Evening Slot

MCQ (Single Correct Answer)

-1

A copper wire is wound on a wooden frame, whose shape is that of an equilateral triangle. If the linear dimension of each side of the frame is increased by a factor of 3, keeping the number of turns of the coil per unit length of the frame the same, then the self inductance of the coil:

decreases by a factor of $$9\sqrt 3 $$

increases by a factor of 27

decreases by a factor of 9

increases by a factor of 3

JEE Main 2019 (Online) 11th January Morning Slot

MCQ (Single Correct Answer)

-1

There are two long co-axial solenoids of same length $$l$$. The inner and outer coils have radii r₁ and r₂ and number of turns per unit length n₁ and n₂, respectively. The ratio of mutual inductance to the self - inductance of the inner-coil is :

$${{{n_2}} \over {{n_1}}}.{{{r_2}^2} \over {{r_1}^2}}$$

$${{{n_2}} \over {{n_1}}}$$

$${{{n_1}} \over {{n_2}}}$$

$${{{n_2}} \over {{n_1}}}.{{{r_1}} \over {{r_2}}}$$

JEE Main 2019 (Online) 10th January Evening Slot

MCQ (Single Correct Answer)

-1

The self induced emf of a coil is 25 volts. When the current in it is changed at uniform rate from 10 A to 25 A in 1s, the change in the energy of the inductance is -

740 J

637.5 J

540 J

437.5 J

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