Physics Quiz 5

Geostationary satellites orbit the earth at a fixed distance of 35,786 km. The speed of the satellite at this distance matches the earth's rotation, thereby keeping the satellite stationary over a particular point on the earth.

Bats navigate and find insect prey using echolocation. They produce ultrasound. The sound waves emitted by bats bounce off objects in their environment. Then, the sounds return to the bats' ears, which are finely tuned to recognize their own unique calls.

The concept was first proposed by Herman Potocnik in 1928 and popularised by the science fiction author Arthur C Clarke in a paper in Wireless World in 1945.

Bats, whales, and dolphins, which hunt in darkness or murky water, find their way by using sound. This is called echolocation.

Detergents clean surfaces or clothes on the principle of surface tension. Adding detergent to water reduces its surface tension.

Asteroids are rocky objects revolving around the sun that are too small to be called planets. The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Mars and Jupiter.

A colour-blind person cannot distinguish between certain colours. Colour blindness often happens when someone cannot distinguish between certain colours. This usually happens between greens and reds, and occasionally blues.

A satellite in vacuum does not require any energy for orbiting. A satellite orbits Earth when its speed is balanced by the pull of Earth's gravity. The gravitational force between the earth and the satellite provides the necessary centripetal force to move around the earth.

The Indian Space Research Organisation (ISRO) is the national space agency of India, headquartered in Bengaluru. ISRO was formed on 15 August 1969. Dr. Vikram A Sarabhai is considered as the founding father of space programmes in India.

During washing of clothes, we use indigo due to its proper pigmental composition. The combination of yellow and blue colours gives white colour. Hence we add blue indigo to remove yellow tint from the white clothes.