Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions

Do the same with the replacement of the earlier transformer by a 40,000-220 V step-down transformer (Neglect, as before, leakage losses though this may not be a good assumption any longer because of the very high voltage transmission involved). Hence, explain why high voltage transmission is preferred?

Electric-field magnitude 'E' at points inside and outside a positively charged spherical conductor having charge Q and a radius R are ______.

If R is the radius of a spherical conductor, V_m the dielectric strength, then the maximum electric-field magnitude to which it can be raised is ______.

Two cells of 1.25 V and 0.75 V are connected in series with anode of one connected to anode of the other. The effective voltage will be ______.

If the kinetic energy of a free electron double, its de-Broglie wavelength changes by the factor ______.

Motion of hole is a convenient way of describing ______.

The electrostatic potential on the surface of a charged conducting sphere is 100V. Two statements are made in this regard S₁ at any point inside the sphere, electric intensity is zero. S₂ at any point inside the sphere, the electrostatic potential is 100 V. Which of the following is a correct statement?

The electrostatic force between the metal plates of an isolated parallel plate capacitor C having a charge Q and area A, is ______.

A coil of circular cross-section having 1000 turns and 4 cm² face area is placed with its axis parallel to a magnetic field which decreases by 10^–2 Wb m^–2 in 0.01 s. The e.m.f. induced in the coil is ______.

A metallic rod of mass per unit length 0.5 kg m^–1 is lying horizontally on a smooth inclined plane which makes an angle of 30°with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction 0.25 T is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is ______.

A charged particle enters in a uniform magnetic field with a certain velocity. The power delivered to the particle by the magnetic field depends on ______.

A current carrying circular loop of radius R is placed in the x-y plane with centre at the origin. Half of the loop with x > 0 is now bent so that it now lies in the y-z plane.

A proton and an alpha particle both enter a region of uniform magnetic field B, moving at right angles to field B. If the radius of circular orbits for both the particles is equal and the kinetic energy acquired by proton is 1 MeV the energy acquired by the alpha particle 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.

The plane in which eddy currents are produced in a conductor is inclined to the plane of the magnetic field at an angle equal to ______.