ISC (Science) ISC Class 12 - CISCE Question Bank Solutions for Physics (Theory)

Name the electromagnetic wave/radiation which is used to study crystal structure.

With reference to semiconductor physics, answer the following question.

What is meant by “Forbidden band" of energy levels?

With reference to semiconductor physics, answer the following question.

In which material “Forbidden band” is absent?

How much is the angular momentum of an electron when it is orbiting in the second Bohr orbit of hydrogen atom?

Using Bohr’s Theory of hydrogen atom, obtain an expression for the velocity of an electron in the n^th orbit of an atom.

If potential difference between the two ends of a metallic wire is doubled, drift speed of free electrons in the wire ______.

The figure below is the Energy level diagram for the Hydrogen atom. Study the transitions shown and answer the following question:

1. State the type of spectrum obtained.
2. Name the series of spectrum obtained.

Using Huygen's wave theory, show that (for refraction of light):

`sin i/sin r = "constant"`

where terms have their usual meaning. You must draw a neat and labelled diagram.

RMS value of an alternating current flowing in a circuit is 5A. Calculate its peak value.

On the basis of Bohr's theory, derive an expression for the radius of the n^th orbit of an electron of hydrogen atom.

State the Bohr's postulate of angular momentum of an electron.

What is the velocity of an electron in the 3rd orbit of hydrogen atom if its velocity in the 1^st orbit is v₀?

The de Broglie wavelength of an electron in the first Bohr’s orbit of hydrogen atom is equal to ______.

Current I flowing through a metallic wire is gradually increased. Show graphically how heating power (P) developed in it varies with the current (I).

In the Figure below, the current-voltage graphs for a conductor are given at two different temperatures, T₁ and T_2.

1. At which temperature T₁ or T₂ is the resistance higher?
2. Which temperature (T₁ or T₂) is higher?

With the help of a neatly drawn labelled diagram, prove the law of reflection on the basis of Huygen’s wave theory.

What is motional emf? State any two factors on which it depends.

What are means by pair annihilation? Write a balanced equation for the same.

What is meant by the term Quantization of charge?

Wavelengths of the first lines of the Lyman series, Paschen series and Balmer series, in hydrogen spectrum are denoted by `lambda_L, lambda_P and lambda_B` respectively. Arrange these wavelengths in increasing order.