Physics MCQs

Notes:
The dimensions of Force are M (mass), L (length) and T^-2 (time). It can also be expressed as [Newton] = [kilogram] [metre] [second]^-2 which is MLT^-2.

Notes:
A body moving with a constant speed in a circle is an example of uniform circular motion. The velocity vector is constant in magnitude but changing in direction. Since, velocity is a vector quantity that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity which leads to change in acceleration.

Notes:
Absolute zero is the lowest possible temperature at which all atomic or molecular motion in matter stops. By international agreement, absolute zero is defined as precisely; 0 K on the Kelvin scale, which is a thermodynamic (absolute) temperature scale; and .273.15 degrees Celsius on the Celsius scale.

Notes:
Acceleration due to gravity is given by the formula : g = GM/r2 According to the question, mass of the second planet is same as that of earth and radius is twice So, using the formula of g, we get the acceleration due to gravity of the second planet as g/4.

Notes:
The key to why clouds float is that the density of the same volume of cloud material is less than the density of the same amount of dry air. Just as oil floats on water because it is less dense, clouds float on air because the moist air in clouds is comparatively less denser than dry air.

Notes:
Total internal reflection is responsible for glittering which occurs when the light from a denser media (liquid) tries to enter less dense media (air in bubble). This reflected light when captured by our eyes is seen as glittering.

Notes:
Magnetic keepers are pieces of soft iron that are placed across the poles of a bar magnet or a horseshoe magnet. They help prevent the loss of magnetism. i.e. help retain the magnetic strength of the magnates placed together.

Notes:
Light scattering in colloidal solutions or particles in suspension is known as Tyndall Effect. It is similar to Rayleigh scattering, in that the intensity of the scattered light depends on the fourth power of the frequency, so blue light is scattered much more strongly than red light.

Notes:
It is possible to transform unpolarized light into polarized light. A light wave that is vibrating in more than one plane is referred to as unpolarized light. Polarized light waves are light waves in which the vibrations occur in a single plane. The process of transforming unpolarized light into polarized light is known as polarization.

Notes:
When the missile is launched with a velocity less than the escape velocity, it will be influenced by our gravitation. So it will constitute a bound system for which the total energy (sum of its kinetic energy and potential energy) will be negative.