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

How does the refractive index of a transparent medium depend on the wavelength of incident light used ?

An equiconvex lens of focal length 'f' is cut into two identical plane convex lenses. How will the power of each part be related to the focal length of the original lens ?

A double convex lens of + 5 D is made of glass of refractive index 1.55 with both faces of equal radii of curvature. Find the value of its radius of curvature.

Give two points to distinguish between a paramagnetic and a diamagnetic substance ?

Using Bohr's postulates, derive the expression for the total energy of the electron in the stationary states of the hydrogen atom ?

Define the terms (i) half-life (T_1/2) and (ii) average life (τ). Find out their relationships with the decay constant (λ).

Using Bohr’s postulates, obtain the expressions for (i) kinetic energy and (ii) potential energy of the electron in stationary state of hydrogen atom.

Draw the energy level diagram showing how the transitions between energy levels result in the appearance of Lymann Series.

Using Bohr’s postulates, obtain the expression for the total energy of the electron in the stationary states of the hydrogen atom. Hence draw the energy level diagram showing how the line spectra corresponding to Balmer series occur due to transition between energy levels.

Using Bohr’s postulates, obtain the expression for total energy of the electron in the n^th orbit of hydrogen atom.

Using Bohr’s postulates, derive the expression for the frequency of radiation emitted when electron in hydrogen atom undergoes transition from higher energy state (quantum number n_i) to the lower state, (n_f).

When electron in hydrogen atom jumps from energy state n_i = 4 to n_f = 3, 2, 1, identify the spectral series to which the emission lines belong.

Use this graph to explain the release of energy in both the processes of nuclear fusion and fission.

The electron in hydrogen atom is initially in the third excited state. What is the maximum number of spectral lines which can be emitted when it finally moves to the ground state?

What characteristic property of nuclear force explains the constancy of binding energy per nucleon (BE/A) in the range of mass number ‘A’ lying 30 < A < 170?

Write two characteristic features observed is photoelectric effect which supports the photon pictures of electromagnetic radiation ?

Draw a graph between the frequency of incident radiation (υ) and the maximum kinetic energy of the electrons emitted from the surface of a photosensitive material state clearly how this graph can be used to determine (i) Planck’s constant and (ii) work function of the material.

Using Bohr’s postulates for hydrogen atom, show that the total energy (E) of the electron in the stationary states tan be expressed as the sum of kinetic energy (K) and potential energy (U), where K = −2U. Hence deduce the expression for the total energy in the n^th energy level of hydrogen atom.

Write the expression for Bohr’s radius in hydrogen atom ?

Give two examples of communication system which use space wave mode.
A TV tower is 80 m tall. Calculate the maximum distance upto which the signal transmitted from the tower can be received.

When light is refracted into a medium, ______________ .

When light is refracted, which of the following does not change?