Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

A primary cell has an e.m.f. of 1.5 volts, when short-circuited it gives a current of 3 amperes. The internal resistance of the cell is(a) 4.5 ohm (b) 2 ohm(c) 0.5 ohm(d) 1/4.5 ohm

If the two ends of a p-n junction are joined by a wire:

The frequency of revolution of a charged particle in a cyclotron does not depend on ‘X’. Identify X.

The energy that should be added to an electron to reduce its de Broglie wavelength from one nm to 0.5 nm is(a) Four times the initial energy      (b) Equal to the initial energy(c) Twice the initial energy(d) Thrice the initial energy

When potential difference is applied across an electrolyte, then Ohm's law is obeyed at:

The audio signal:

Which of the following would you prefer to use while reading small letters found in a dictionary?

The electrostatic energy of the system made by two electric dipoles kept at a distance 'r' is proportional to :