Physics
RADAR is used for:

receiving a signals in a radio receiver.
detecting and locating the position of objects such as Aeroplanes.
locating submerged submarines.
locating geostationary satellites.

ANSWER DOWNLOAD EXAMIANS APP

Physics
On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because:

mercury is a metal.
density of mercury is greater than that of water.
cohesion of mercury is greater than its adhesion with glass.
cohesion of water is greater than its adhesion with glass.

ANSWER DOWNLOAD EXAMIANS APP

Physics
Stars twinkle because

None of these
the intensity of light emitted by them changes with time.
the refractive index of the different layers of the earth's atmosphere ch
the distance of the stars from the earth changes with time.

ANSWER DOWNLOAD EXAMIANS APP