Physics Quiz 6

The air layer between two shirts behaves like insulating media. Air in general is a good thermal insulator, but it can transmit heat through convection. However, if the air pockets inside the insulating material are separated from each other, heat flow from one air pocket to another cannot happen easily.

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.

Decibel (db) is the unit used for the intensity of sound. The 'normal' hearing frequency range of a healthy young person is about 20 to 20,000Hz. Though a 'normal' audible range for loudness is from 0 to 180dB, anything over 85dB is considered damaging.

On a rainy day, due to the Interference of light, small oil films on water show brilliant colours. Interference is a phenomenon in which two waves superimpose to form a resultant wave of the greater, lower, or same amplitude.

ENIAC (Electronic Numerical Integrator and Computer) was the first programmable, electronic, general-purpose digital computer made in 1945 by the United States. ENIAC weighed over 30 tons with over 17,000 valves (vacuum tubes).

When a person walking in bright Sunlight enters a dark room, he is not able to see clearly for a little while because the iris is unable to dilate the pupil immediately.

Speed of light in air is 3×10⁸ m/s and speed of light in common glass is 2×10⁸ m/s.

The major difference between laser light and other light sources (such as a light bulb) is that laser light is monochromatic, directional and coherent. Monochromatic means that all of the light produced by the laser is of the same frequency, amplitude and phase.

The modulus of rigidity, also known as shear modulus, is the ratio of shearing stress to shearing strain. It is the elastic coefficient when a shear force is applied resulting in lateral deformation.

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