N
 Newton’s first law: Everybody continues in its state of rest or of uniform motion in a straight line unless it is compelled by an external force to change that state. Newton’s second law: The rate of change of momentum of a body is directly proportional to external force acting on it and takes place in the direction of force. Newton’s third law: For every action there is equal and opposite reaction. Non-conservative force: If the work done by a force acting on a body depends on path followed then it is called as non-conservative force. Non-polar dielecric: It is the substance in which the net electric dipole moment is zero because of its symmetrical structure. The center of gravity of positive and negative charges will coincide. Newton’s universal law of gravitation: Every two bodies in the universe attract each other with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between the masses. Nano materials: Materials whose dimensions are less than 100nm. Normal force: When two bodies are in contact or when one body is placed over another body, the contact force which either body exerts on other body normal to contact surface is called normal force or normal reaction. Nucleon: The charge independence of nuclear interactions suggests that neutron and protons are two states of single entity, the nucleon. Neutrino: An elementary particle introduced by Pauli in weak interactions involving beta decay to avoid violation of law of conservation of energy and angular momentum. Node: The position of particle in a wave which always remains at mean position is referred to as Node. Node is a position of zero displacement and maximum strain. N-type semiconductor: A semiconductor doped with donor impurity atoms. This type of semiconductor has electrons as predominant charge carriers. Newton’s law of cooling: The rate of loss of heat from the body (or rate of cooling of body) is directly proportional to the difference in temperatures of body and surroundings. Non-Inertial frames of reference: The frames relative to which an un accelerated body appears accelerated are called non-inertial frames. All accelerated frames are non-inertial frames. Norton’s theorem: In a linear network consisting of emfs’ and resistances when viewed from its output terminals, is equivalent to constant current source with parallel effective resistance. The constant current is equal to current which would flow in a short circuit placed across terminals, and the parallel resistance is resistance of network when viewed from open circuited terminals after all emf’s have been removed & replaced by internal resistances.   Negative feedback: When feedback energy is out of phase with input signal and opposite it, it is called negative effect. Non-ferrous alloy: A metal alloy for which iron is not prime constituent. Norton’s theorem: In a linear network consisting of emf’s and resistances when viewed from its output terminals, is equivalent to constant current source with parallel effective resistance. The constant current is equal to current which would flow in a short circuit placed across terminals, and the parallel resistance is resistance of network when viewed from open circuited terminals after all emf’s have been removed & replaced by internal resistances. Nutation: The rise and fall of axis of rotation about its position of dynamic equilibrium is called as Nutation.