Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Physics

Answer the following question.
Define the term "Intensity" in the photon picture of electromagnetic radiation.

Answer the following question.
Two infinitely long straight wire A₁ and A₂ carrying currents I and 2I flowing in the same direction are kept' distance apart. Where should a third straight wire A₃ carrying current 1.5 I be placed between A₁ and A₂ so that it experiences no net force due to A₁ and A₂? Does the net force acting on A₃ depend on the current flowing through it?

Use Einstein's photoelectric equation to show how from this graph,
(i) Threshold frequency, and
(ii) Planck's constant can be determined.

A variable resistor R is connected across a cell of emf ε and internal resistance r as shown in the figure. Draw a plot showing the variation of
(i) Terminal voltage V and
(ii) the current I, as a function of R.

Choose the correct answer from given options
Photons of frequency v are incident on the surface of two metals A and B of threshold frequency 3/4 v and 2/3 v, respectively. The ratio of maximum kinetic energy of electrons emitted from A to that from B is

If 10⁹ electrons move out of a body to another body every second, how much time is approximately required to get a total charge of 1C on the other body?

Electrostatic force is the force exerted by ______.

If a charge q₀ is there in an electric field caused by several point charges q_i. The potential energy of q₀ is given by ________.

If a current I is flowing in a straight wire parallel to x-axis and magnetic field is there in the y-axis then, ______.

According to Ampere's circuital law, ______.

Magnetic intensity is given by ______.

If `vec"H"` = magnetic intensity, `chi` = susceptibility, magnetic moment per unit volume `vec"M"` equals ______.

According to Einstein's photoelectric equation, the plot of the kinetic energy of the emitted photoelectrons from a metal versus the frequency of the incident radiation gives a straight line, whose slope ______.

Each photon has the same speed but different ______.

Basic materials used in the present solid state electronic devices like diode, transistor, ICs, etc are ______.

Diffusion in a p-n junction is due to ______.

An electrical cable of copper has just one wire of radius 9 mm. Its resistance is 5 ohm. This single copper wire of the cable is replaced by 6 different well insulated copper wires each of radius 3 mm. The total resistance of the cable will now be equal to ______.