Physics Quiz 4

Electrostatic precipitators are used for air pollution control, particularly for removing harmful particulate matter from waste gases at industrial facilities and power-generating stations.

Spread his hands outwards should a person on a freely rotating turntable do to decrease his (angular) speed. A person on the rotating table will maintain approximately the same angular momentum during the spin. When he spreads his hands outward, the angular rotation is decreased.

Aluminium and its alloys are used for making aircraft and rockets, due to their high strength at relatively low density.

The apparent weight of a man in a lift is less than the real weight when the lift is going down with an acceleration. When a lift accelerates upwards, the apparent weight of the person inside it increases; and when a lift accelerates downwards, the apparent weight of the person inside it decreases.

X-ray inspection systems are mostly capable of detecting defects and contaminants in precious stones and diamonds.

The working of the quartz crystal in the watch is based on Piezoelectric effect. Piezoelectric Effect is the ability of certain materials to generate an electric charge in response to applied mechanical stress. A commonly known piezoelectric material is quartz.

Lambert's law is related to Illumination. This law stated that the loss of light intensity when it propagates in a medium is directly proportional to intensity and path length.

Heat transfer horizontally within the atmosphere is called advection. Advection is the transfer of heat or matter by the flow of a fluid, especially horizontally in the atmosphere or the sea. The horizontal movement of the air is comparatively more significant than the vertical movement.

Energy of Ultraviolet rays is greater than Infrared rays. Radio waves have photons with the lowest energies. Microwaves have a little more energy than radio waves. Infrared has still more, followed by visible, ultraviolet, X-rays and gamma rays. Cosmic rays are (not part of the electromagnetic spectrum) high-energy outer space particles.

When the two ice cubes are pressed together, melting point of ice is lowered, so they melt to form a thin layer of water (between them). On releasing the pressure, the water formed freezes because decrease in pressure raises the freezing point. Hence they unite to form one cube. When water freezes, water molecules form a crystalline structure maintained by hydrogen bonding.