Physics MCQs

Notes:
Total internal reflection can take place when light travels from diamond to glass.
When light travels from one medium to another it changes speed and is refracted. If the light rays are travelling for a less dense material to a dense medium they are refracted towards the normal and if they are travelling from a dense to less dense medium they are refracted away from the normal.
For total internal reflection to occur the light must travel from a dense medium to a less dense medium (e.g. glass to air or water to air).As the angle of incidence increases so does the angle of refraction. When the angle of incidence reaches a value known as the critical angle the refracted rays travel along the surface of the medium or in other words are refracted to an angle of 90°. The critical angle for the angle of incidence in glass is 42°.

Notes:
Alpha particle consists of two protons and two neutrons and hence the charge of the alpha particle is +2.

Notes:
Alpha, beta and gamma radiations are emitted during the radioactive decay process. Alpha is positive particle with double positive charge, beta particle is an electron and hence negative charge, gamma radiation is neutral.

Notes:
According to Newton’s third law of motion, to every action there is an equal and opposite reaction’. It indicates that when one object exerts a force on another object, the second object instantaneously exerts a force back on the first object. These two forces are always equal in magnitude, but opposite in direction.

Notes:
The number of waves or vibrations passing through a point in one second is called Frequency. The SI (System International) Unit of Frequency is Hertz(Hz). It is named for Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves.

Notes:
The force acting on an object perpendicular to the surface is called thrust. It is a reaction force described quantitatively by Isaac Newton’s second and third laws. Force, and thus thrust, is measured in the International System of Units (SI) as the newton.

Notes:
In pressure cooker as the name suggest, the developed high pressure raises the boiling point of water to about 120°C-140°C. This raised temperature not only speed up cooking but also proper cooking of foods cooked inside it.

Notes:
The average kinetic energy of gas molecules is directly proportional to absolute temperature only. This implies that all molecular motion ceases if the temperature is reduced to absolute zero.

Notes:
Candela, it is the standard unit of luminous intensity, the luminous power per unit solid angle emitted by a point light source in a particular direction. In simple, it refers to candle.