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

A uniform magnetic field of 3000 G is established along the positive z-direction. A rectangular loop of sides 10 cm and 5 cm carries a current of 12 A. What is the torque on the loop in the different cases shown in fig.? What is the force on each case? Which case corresponds to stable equilibrium?

The instrument for the accurate measurement of the e.m.f of a cell is ______.

Kirchhoff’s second law is a consequence of law of conservation of ______.

Figure shows current in a part of an electrical circuit. Then current I is ______.

Consider the motion of a charged particle in a uniform magnetic field directed into the paper. If velocity v of the particle is in the plane of the paper the charged particle will ______.

Considering the magnetic field of the earth, the correct relation of the geographic pole and the magnetic pole is ______.

Sodium and copper have work function 2.3 eV and 4.5 eV respectively. Then, the ratio of the wavelengths is nearest to ______.

Nuclear mass M is found to be ______.

Correct expression for mass defect Δm is ______.

The Gaussian surface ______.

Assertion: Kirchhoff’s junction rule follows from conservation of charge.
Reason: Kirchhoff’s loop rule follows from conservation of momentum.

The Kirchhoff's second law (ΣiR = ΣE), where the symbols have their usual meanings, is based on ______.

Two points A and B are situated at a distance x and 2x respectively from the nearer pole of a magnet 2 cm long. The ratio of magnetic field at A and B is ______.

The surface considered for Gauss’s law is called ______.

Which of the following statements is not true about Gauss’s law?

The SI unit of magnetic field intensity is ____________.