Electric Charges and Fields — Physics STD 12 Science — Question

A charge is being induced to a sphere with the help of another charged sphere. The extent of induction increase if ____________?

The short range attractive nuclear forces that are responsible for the binding of nucleons in a nucleus are supposed to be caused by the role played by the particles called:

A steady current i is flowing through a conductor of uniform cross-section. Any segment of the conductor has

(a) Zero charge	(b) Only positive charge
(c) Only negative charge	(d) Charge proportional to current i

A photon of wavelength 4400 Å is passing through vacuum. The effective mass and momentum of the photon are respectively

(a) 5	(b) 5
(c) Zero, 1.5	(d) 5

A bar magnet of magnetic moment  J/T is free to rotate in a horizontal plane. The work done in rotating the magnet slowly from a direction parallel to a horizontal magnetic field of 4 ×  T to a direction 60° from the field will be

(a) 0.2 J

(b) 2.0 J

(c) 4.18 J

(d) 2 × 102 J

The transformation ratio in the step-up transformer is

(a) 1

(b) Greater than one

(c) Less than one

(d) The ratio greater or less than one depends on the other factors

The half-life period of radium is 1600 years. Its average life time will be

(a) 3200 years

(b) 4800 years

(c) 2319 years

(d) 4217 years

In Young's double slit experiment, if monochromatic light is replaced by white light

(a) All bright fringes become white

(b) All bright fringes have colours between violet and red

(c) Only the central fringe is white, all other fringes are coloured

(d) No fringes are observed

Image formed on the retina is

(a) Real and inverted	(b) Virtual and erect
(c) Real and erect	(d) Virtual and inverted