The principle of AC generator is MCQ with Answer and Explanation

Explanation:
A potentiometer uses a long wire of uniform cross-section and composition. When a constant steady current flows through it, Ohm's law (V = IR) and the resistance formula (R = rhoL/A) combine to give V = I(rho/A)L. Since I, rho, and A are constant, the potential drop V is strictly directly proportional to the length L of the wire.

Explanation:
Action (bullet forward) and reaction (gun backward). Also momentum conservation.

Explanation:
In Einstein's photoelectric theory, electrons are bound to the metal lattice. The 'work function' (often denoted by Phi or W) is defined strictly as the absolute minimum thermodynamic work (energy) needed to overcome these binding forces and remove an electron from the surface into a vacuum. If incident photon energy (hf) is less than the work function, absolutely no emission occurs.