Science (English Medium) Class 12 - CBSE Question Bank Solutions for Physics

A bar magnet of magnetic moment 1.5 J T^-1 lies aligned with the direction of a uniform magnetic field of 0.22 T.

What is the torque on the magnet in cases (i) and (ii)?

A circular coil of 16 turns and radius 10 cm carrying a current of 0.75 A rests with its plane normal to an external field of magnitude 5.0 × 10⁻² T. The coil is free to turn about an axis in its plane perpendicular to the field direction. When the coil is turned slightly and released, it oscillates about its stable equilibrium with a frequency of 2.0 s⁻¹. What is the moment of inertia of the coil about its axis of rotation?

A magnetic dipole is under the influence of two magnetic fields. The angle between the field directions is 60°, and one of the fields has a magnitude of 1.2 × 10^–2 T. If the dipole comes to stable equilibrium at an angle of 15° with this field, what is the magnitude of the other field?

Work done by a uniform electric field 'E' in moving a charge 'q' at a distance 'd' from a to b is ______.

If a current I is flowing in a straight wire parallel to x-axis and magnetic field is there in the y-axis then, ______.

According to Ampere's circuital law, ______.

Compass needle of magnetic moment m placed in a uniform magnetic field, experiences a torque equal to ______.

Magnetic potential energy U_m of compass needle of known magnetic moment m in a uniform magnetic field is ______.

A microscope is focussed on a mark on a piece of paper and then a slab of glass of thickness 3 cm and refractive index 1.5 is placed over the mark. How should the microscope be moved to get the mark in focus again?

What is the percentage of the mass of an atom concentrated in the nucleus?

Two cells of emfs approximately 5 V and 10 V are to be accurately compared using a potentiometer of length 400 cm.

A milli voltmeter of 25 milli volt range is to be converted into an ammeter of 25 ampere range. The value (in ohm) of necessary shunt will be ______.

Assertion: The poles of magnet can not be separated by breaking into two pieces.

Reason: The magnetic moment will be reduced to half when a magnet is broken into two equal pieces.

A magnetic dipole is acted upon by two magnetic fields which are inclined to each other at an angle of 75°. One of the fields has a magnitude of 15 mT. The dipole attains stable equilibrium at an angle of 30° with this field. The magntidue of the other field (in mT) is close to ______.