Wave Optics — Physics STD 12 Science — Question

The patient is asked to drink  for examining the stomach by X-rays because X-rays are

(a) Reflected by heavy atoms	(b) Refracted by heavy atoms
(c) Less absorbed by heavy atoms	(d) More absorbed by heavy atoms

The colour of the second line of Balmer series is

(a) Blue

(b) Yellow

(c) Red

(d) Violet

Li nucleus has three protons and four neutrons. Mass of lithium nucleus is 7.03.6005 amu. Mass of proton is 1.007277 amu and mass of neutron is 1.008665 amu. Mass defect for lithium nucleus in amu is:

In a parallel plate capacitor of capacitance C, a metal sheet is inserted between the plates, parallel to them. If the thickness of the sheet is half of the separation between the plates. The capacitance will be

(a)

(b)

(c) 4C

(d) 2C

Heavy water is

(a) Water at 4 ℃

(b) Compound of deuterium and oxygen

(c) Compound of heavy oxygen and heavy hydrogen

(d) Water, in which soap does not lather

If the length of potentiometer wire is increased, then the length of the previously obtained balance point will:

A long straight wire of circular cross section of radius'a carries a steady current 1. The current is uniformly distributed across its cross section. The ratio of magnitudes of the magnetic field at a point a/2 above the surface of wire to that of a point a 2 below its surface is

An electric dipole is put in north-south direction in a sphere filled with water. Which statement is correct

(a) Electric flux is coming towards sphere

(b) Electric flux is coming out of sphere

(c) Electric flux entering into sphere and leaving the sphere are same

(d) Water does not permit electric flux to enter into sphere

Which causes the formation of rainbow ?

In a double slit arrangement fringes are produced using light of wavelength 4800 Å. One slit is covered by a thin plate of glass of refractive index 1.4 and the other with another glass plate of same thickness but of refractive index 1.7. By doing so the central bright shifts to original fifth bright fringe from centre. Thickness of glass plate is

(a) 8 mm

(b) 6 mm

(c) 4 mm

(d) 10 mm