Physics Quiz 2

In the process of magnetization of a bar, the entire bulk of the bar gets magnetised. By the process of magnetisation, the formed pieces develop North polarity on one end or side and South polarity on the other end or side, in a very short period of time.

Smog is a kind of air pollution. The smoke usually came from large amounts of coal burning in an area and is caused by a mixture of smoke and sulphur dioxide (SO₂).

Gas expands more than liquid for the same tiny change in temperature. Hence, gas thermometers are more sensitive than liquid thermometers.

Optical fibre works on the principle of total internal reflection. When light ray strikes at the internal surface of an optical fibre cable called such that incidence angle is greater than critical angle, then incident light ray reflects in the same medium and this phenomenon repeats.

Hypermetropia, also known as long-sightedness, is a defect of vision in which a person can't see the nearby object clearly (appears blurred), though can see the distant objects clearly. The near point of a hypermetropic eye is greater than 25 cm.

By lowering his hands while catching the cricket ball, the player allows a longer time for momentum change (lower the momentum), thereby preventing his hands from getting injured.

Rocket engines and boosters carry both fuel and an oxidizer. For solid fuel, the components are aluminium and ammonium perchlorate. For liquid fuel, the components are liquid hydrogen and liquid oxygen. When combined, the fuels release water, which allows the rocket to leave the ground.

The most common material used for the heating element is Nichrome. Nichrome is the alloy of the Nickel and chromium; in this alloy, the nickel is 80% and the chromium is 20%. It is corrosion-resistant and has a high melting point of about 1400 degree C.

Adiabatic demagnetization is a process by which the removal of a magnetic field from certain materials serves to lower their temperature. It comes under magnetic cooling, exploiting paramagnetic properties to cool some materials down.

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.