Artificial satellites - class-VIII

The total energy of a satellite in an orbit of radius r is E = -GMm / (2r). The energy required to move from 2R to 4R is E2 - E1 = (-GMm / 8R) - (-GMm / 4R) = (-GMm + 2GMm) / 8R = GMm / 8R.

Answer is A.
Geostationary satellites are positioned at an height above the Earth about $36,000\ km$. At this height, they rotate around the Earth at the same speed as the Earth rotates around its axis, so in effect remaining stationary above a point on the Earth (normally directly overhead the equator).
As they remain stationary, they are ideal for use as communications satellites and also for remote imaging as they can repeatedly scan the same points on the Earth beneath them.
Their great height is that they can view the whole Earth disk below them, rather than a small subsection, and they can scan the same area very frequently.
Hence, the statement is true.

To receive and broadcast audio and video signals
Transponders basically receive and transfer signals in satellite communication. Hence, it can be used to broadcast received audio and video signals.

Aryabhatta
The first satellite by ISRO into the space was Aryabhatta launched on April 19, 1975.

Remote Sensing is the process of acquiring Information about an object or phenomenon without making actual physical contact within, as opposed to onsite observation.

A celestial body that revolves around a planet is defined as a satellite (natural or artificial).

Jupiter is having largest no. of satellites.

The first Indian built rocket was launched from Thumba on the outskirts of thiruvananthpuram on November 21 1963.

Chandrayaan-1 was India's first lunar probe. It was launched by Indian Space Research Organisation (ISRO) in Ocyuber 2008 and operated until August 2009. The vehicle was successfully inserted into lunar orbit on 8 November, 2008. The greatest achievement of Chandrayaan is the discovery of the widespread presence of water molecules in the lunar soil.

The scientific payload in Chandrayaan contained 5 Indian Instruments and 6 instruments from other countries.

The scientific payload in Chandrayaan contained 5 Indian instruments and 6 instruments from other countries.

The mass of Chandrayaan was 1380 kg at launch, 675 kg at lunar orbit and 523 kg after releasing the impactor. It was cuboidal in shape. The spacecraft used a bipropellant  integrating propulsion system to reach lunar orbit as well as its maintenance while operating the moon. The power plant consisted of one 440 N engine and eight 220 thrusters. Fuel and oxidiser were stored in two tanks of 390 litres each.

 The Chandrayaan used a bipropellant  integrating propulsion system to reach lunar orbit as well as orbit and altitude maintenance while operating the Moon. The power plant consisted of one 440 N engine and eight 220 thrusters. Fuel and oxidiser were stored in two tanks of 390 litres each.

The Chandrayaan was mainly powered by its solar array, which included one solar panel covering a total area of 2.15 x 1.8 m generating 750 W of peak power, which was stored in a 36 Ah lithium-ion battery for use during eclipses.