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

Draw equipotential surfaces for (i) an electric dipole and (ii) two identical positive charges placed near each other.

How will the energy of a hydrogen atom change if n increases from 1 to ∞?

State Bohr's postulate to explain stable orbits in a hydrogen atom. Prove that the speed with which the electron revolves in n^th orbit is proportional to `(1/"n")`.

A long straight wire of radius 'a' carries a steady current 'I'. The current is uniformly distributed across its area of cross-section. The ratio of the magnitude of magnetic field `vecB_1` at `a/2` and `vecB_2` at distance 2a is ______.

What is meant by ionisation energy?

Write the ionisation energy value for the hydrogen atom.

Read the following paragraph and answer the questions.

1. Explain the reason for the jumping of the ring when the switch is closed in the circuit.
2. What will happen if the terminals of the battery are reversed and the switch is closed? Explain.
3. Explain the two laws that help us understand this phenomenon.

Specify the transition of an electron in the wavelength of the line in the Bohr model of the hydrogen atom which gives rise to the spectral line of the highest wavelength ______.

The radius of the n^th orbit in the Bohr model of hydrogen is proportional to ______.

State three postulates of Bohr's theory of hydrogen atom.

Find the angular momentum of an electron revolving in the second orbit in Bohr's hydrogen atom.

The wavelength of the second line of the Balmer series in the hydrogen spectrum is 4861 Å. Calculate the wavelength of the first line of the same series.

The energy of an electron in the n^th orbit of the hydrogen atom is E_n = -13.6/n²eV. The negative sign of energy indicates that ______.

The given figure shows a long straight wire of a circular cross-section (radius a) carrying steady current I. The current I is uniformly distributed across this cross-section. Calculate the magnetic field in the region r < a and r > a.

Briefly explain various ways to increase the strength of the magnetic field produced by a given solenoid.

(i) In Young's double-slit experiment, deduce the condition for (a) constructive and (b) destructive interferences at a point on the screen. Draw a graph showing variation of intensity in the interference pattern against position 'x' on the screen.

(b) Compare the interference pattern observed in Young's double-slit experiment with single-slit diffraction pattern, pointing out three distinguishing features.

Why is base band signal not transmitted directly? Give any two reasons

Derive an expression for path difference in Young’s double slit experiment and obtain the conditions for constructive and destructive interference at a point on the screen.

The intensity at the central maxima in Young’s double slit experiment is I₀. Find out the intensity at a point where the path difference is` lambda/6,lambda/4 and lambda/3.`

Given the ground state energy E₀ = - 13.6 eV and Bohr radius a₀ = 0.53 Å. Find out how the de Broglie wavelength associated with the electron orbiting in the ground state would change when it jumps into the first excited state.