Showing posts with label Displacement. Show all posts
Showing posts with label Displacement. Show all posts


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Dimension of a space or object is informally defined as minimum number of coordinates required to specify any point with in it. Dimension of physical quantity is combination of basic physical dimensions (usually mass, length, time, temperature etc) which describe it.

Dimensional Analysis

Analysis to find relation among physical quantities by using their dimensions.

Dimensional Equation

When the dimensional formula of physical quantity is expressed in the form of an equation, then such equation is known as dimensional equation. 

Dimensional Formula

An expression showing the powers to which the fundamental units are to be raised to obtain one unit of derived quantity is called as dimensional formula.


It is an electronic device that rectifies electric current i.e. current flow in one direction only.

Dipole Moment

The product of either charge in an electric dipole with the distance separating them.

Dipole Relaxation

When external alternating field is applied to some materials it leads to formation of permanent dipole moment, the phenomenon termed as dipole relaxation. 


A dipole is an entity in which equal positive and negative charges are separated by a small distance.

Dirac Constant

Constant used in quantum mechanics equal to Planck’s constant divided by 2π. It has a value of  1.05 x 10-34 joules seconds.

Direct Band Gap Semiconductor

The semi conductor in which an electron in conduction band can fall to any empty state in valence band giving off the energy difference (energy gap) as a photon of light. 

Direct Current

Continuous electric current flowing in one direction without substantial variation in magnitude is called as direct current.

Directly Ionizing Radiation

Comprises charged particles (electrons, protons, charged particles, heavy ions) that deposit energy in the absorber through a direct one-step process involving Coulomb interactions between the directly ionizing charged particle and orbital electrons of the atoms in the absorber.


Discrimination in radiation detection circuits refers to the process of distinguishing between different types of radiation on the basis of pulse height. A discriminator circuit selects the minimum or maximum pulse height that is to be counted.

Disintegration Constant

See decay constant.


Physical process by which atomic nucleus emits particles or energetic rays, which make composition of nucleus to change.


A linear crystalline defect around which there is atomic misalignment.

Dispersion of Light

The phenomenon of splitting of light into different colors is called as dispersion. It arises due to variation of refractive index with wavelength.


Whenever the speed of wave depends on its frequency, supporting medium is called dispersive. The phenomenon of changing of shape by wave having range of frequencies in a medium is called as dispersion.

Dispersive Power of Grating

The rate of variation of angle of diffraction with the wavelength of light is called dispersive power of grating.

Dispersive Power of Prism

The rate of variation of the angle of deviation with the wavelength of light is called as dispersive power of prism.

Dispersive Power

The ratio of angular dispersion between two colors to deviation of mean ray produced by the prism is called dispersion power of material of prism for those colors. 


The shortest distance between the initial and final positions of a body.


Distance travelled by an object in a specified direction.

Displacement Current

Changing electric field leads to a current which flows as long as electric field is changing and produces magnetic field. The current is called as displacement current.   

Difference between Distance & Displacement

Displacement is a vector quantity as it is associated with direction,but distance is a scalar quantity which does not give any information about direction of motion.Distance and displacement magnitude are numerically equal only when the body travels in a straight line from A to B(i.e the shortest distance from a point to another). Also distance has always a non-zero magnitude,but displacement can be zero if the body returns to the point of origin at the end of motion.