If there were no atmosphere, the length of the day on the earth will
(a) Remain the same
(b) Decrease
(c) Increase
(d) None of these
Answer:
Chromatic aberration in a lens is caused by
(a) Dispersion
(b) Diffraction
(c) Reflection
(d) Interaference
Answer:
Splitting of white light into seven colours is due to
(a) Reflection
(b) Interference
(c) Diffraction
(d) Refraction
Answer:
Which one of the following is used to remove astigmatism for a human eye?
(a) Cylindrical lens
(b) Prismatic lens
(c) Concave lens
(d) Convex lens
Answer:
The principle of light based on which shadow is formed, is
(a) Refraction
(b) Reflection
(c) Rectilinear propagation
(d) Diffraction
Answer:
The resistance of a wire depends on its
(a) Area of cross-section
(b) Length
(c) Shape
(d) Materical
Answer:
The conductivity of a superconductor is
(a) Zero
(b) Very small
(c) Very large
(d) Infinite
Answer:
The coil of an electric heater is made of
(a) Nichrome
(b) Aluminium
(c) Tungsten
(d) None of these
Answer:
Laws of heating are given by
(a) Bohar
(b) Lenz
(c) Joule
(d) Ohm
Answer:
Electricity is produced through dry cell from
(a) Nuclear energy
(b) Mechanical energy
(c) Chemical energy
(d) Thermal energy
Answer: