The sun appears red at sunrise and sunset while it appears white at noon, because:
- (A) It is cooler at sunrise and at sunset
- (B) Of refraction
- (C) Of diffraction leading to red end of the spectrum reaching the earth
- (D) Of scattering of light due to dust particles and air molecules
- (D) Of scattering of light due to dust particles and air molecules
Sun appears red in color during sunrise and sunset due to:
- (A) The fact that sun emits only red color at that time
- (B) Red light having longer wavelength scatters away
- (C) The fact that all other colors scatter away except red
- (D) Of diffraction leading to red end of the spectrum reaching the earth
- (B) Red light having longer wavelength scatters away
The beautiful color patterns exhibited by a peacock in its tail feathers are due to:
- (A) Interference of light
- (B) Selective absorption of light
- (C) Selective reflection of light
- (D) Natural color pattern of feathers
- (B) Selective absorption of light
T.V transmission cannot cover a very large area because:
- (A) Picture cannot be transmitted clearly after a specific distance
- (B) The strength of T.V waves is very limited
- (C) The shape of the earth is spherical
- (D) The air is not a good conductor of light and sound waves
- (C) The shape of the earth is spherical
Copper wires are generally used for electrical power transmission instead of iron wire because:
- (A) Copper is cheaper than iron
- (B) Copper is lighter than iron
- (C) Copper is a better conductor of electricity than iron
- (D) Copper can take higher power than iron
- (C) Copper is a better conductor of electricity than iron
Tungsten is used for the manufacture of the filament of an electric bulb because:
- (A) It is a good conductor
- (B) It is economical
- (C) It is malleable
- (D) It has a very high melting point
- (D) It has a very high melting point
Air is completely removed from an electric bulb to prevent:
- (A) Loss of light due to absorption
- (B) Bursting of the bulb
- (C) Oxidation of tungsten filament
- (D) Cracking of bulb immediately
- (C) Oxidation of tungsten filament
When the door of an operating refrigerator is opened the temperature of the room will:
- (A) Decreases
- (B) Increases
- (C) Remained unchanged
- (D) Fall down immediately
- (B) Increases
On earth a moving body ordinarily comes to rest by itself because of:
- (A) Law of inertia
- (B) Forces of friction
- (C) Gravitational force
- (D) Conversation of momentum
- (B) Forces of friction
The necessary centripetal force to the moving car around a corner track is provided by:
- (A) Coulomb’s force
- (B) Gravitational force
- (C) Force of friction
- (D) Centrifugal force
- (C) Force of friction