(a) A jet engine combines oxygen from the air with fuel at high temperature. There is usually a spark to ignite the fuel vapor, but once the engine starts running , it will continue running until it runs out of fuel or air. A rocket, carries its own supply of liquid oxygen for combustion.

(d) Brahmagupta was an Indian mathematician and astronomer who had written numerous books on mathematics and astronomy. He anticipated Newton by declaring that all things gravitate to the earth.

(a) As monkey and bullet both fall under the same gravitational force, so bullet will hit exactly the same point it has been aimed.

(a) Cryogenics is the study of the production of very low temperature (below –150 °C, – 238 °F or 123 K) and the behavior of materials at those temperatures. In magnetic levitation, a strong and spatially varying magnetic field exerts an upward force on a body that is sufficient to counteract its weight due to gravity. This effect can be enhanced by immersing the body in cold oxygen gas, which provides a further strong and adjustable buoyancy force that allows a wide range of materials to be levitated in an open, unpressurized vessel. Cryogenic liquids are also used in the space program. For example, cryogens are used to propel rockets into space. A tank of liquid hydrogen provides the fuel to be burnt and a second tank of liquid oxygen is kept for helping combustion. Cryogenic processes are also used to supply “banks” storing eye corneas, blood, and sperm for future surgical procedures. In 1961 American surgeon Irving S. Cooper introduced a freezing technique called cryosurgery. Cryosurgery is relatively bloodless because the low temperatures used constrict the blood vessels, decreasing the loss of blood.

(c) The anomalous expansion of water as it cools from 4°C to 0°C means that the density of water is greatest at 4°C. So the ice that forms in cold weather forms at the top of the water (where the less dense coldest water gathers) and then acts as an insulating barrier preventing the water underneath from getting much colder (because heat cannot escape).

(b) In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents through each component. The wiring for most homes is parallel .In parallel circuit each branch receives equal current. If one branch in the circuit is broken, electric current will still flow in other branches.

(a) Earth’s magnetic field diverts them torwards its poles.

(a) X-ray computed tomography (CT) is a medical imaging method employing tomography created by computer processing. This technique is used to generate a three dimensional image of the inside of an object.

(d) There is no significant production of silicon wafers in India . · Tariffs are determined under the Electricity Act.

(d) · In 2010 International Team of Astronomers confirmed Albert Einstein’s theory of general relativity and that the expansion of the universe is accelerating after looking at data from the Hubble Space Telescope. There is an unknown source of energy in the universe which is causing the cosmic expansion to speed up. In 2016 Japanese researchers’ study finds that the expansion of the universe could be explained by a cosmological constant, as proposed by Einstein in his theory of general relativity. In 2018 Hubble Space Telescope captured image of a phenomenon called Einstein Ring. Einstein in his theory of general relativity, had suggested that a massive object would warp space and time.