General Awareness – Physics
1-The process of using X rays in medical diagnosis is called radiography.
2-The radiations that have wavelengths larger than those of visible light is Infrared.
3-The radiations that can be detected by Thermopiles,voltmeters etc are infrared.
4-Infrared radiations can be used to take photographs of objects in darkness.
5-The process of curing certain diseases using X rays is called radio therapy.
6-All electronic magnetic waves are in transverse in nature.
7-Atmospheric ozone is depleted in recent years as a result of chemical reactions with fluorocarbons.
8-Rays that are produced in the decay of certain elementary particles are Gamma rays.
9-The radiation of shorter wavelength are Gamma rays.
10-The most penetrating radiations are Gamma rays.
11-A medium transmits sound wave through it by virtue of its elasticity and inertia.
12-Energy is carried continuously by progressive waves.
13-The points in a standing wave where the amplitude is maximum are called antinodes.
14-A wave that consists of set of crests and troughs is known as transverse wave.
Transverse plane wave
15-A wave that consists of a set of compressions and rarefactions is called longitudinal wave.
16-Periodic vibrations of decreasing amplitude are called Damped vibrations.
17-When a body is set into vibrations and then left to itself , the vibrations are called Free Vibrations.
18-When the body executes vibrations under the action of an external periodic force then the vibrations of the body are called Forced Vibrations.
19-Sound can not travel through vacuum.
20-S.I unit of wavelength is metre.
21-The velocity of sound is the product of its wavelength andfrequency.
22-The waves that oscillates between nodes and antinodes is called stationary wave.
23-When soldiers cross a suspension bridge, they are asked to break their steps to prevent resonance.
24-The elevation in a transverse wave is called a crest.
25-The distance travelled by the wave in a time period is called wavelength.
26-The unit of frequency is Hertz.
27-The depression in a transverse wave is called a trough.
28-In longitudinal waves the distance between any two successive compressions or rarefactions is equal to wavelength.
29-Particles undergo minimum displacement at nodes in a stationary wave.
30-The wave theory of light was proposed by Huygen.