ISC (Science) ISC Class 12 - CISCE Question Bank Solutions

Draw energy level diagram for a hydrogen atom, showing the first four energy levels corresponding to n=1, 2, 3 and 4. Show transitions responsible for:
(i) Absorption spectrum of Lyman series.
(ii) The emission spectrum of the Balmer series.

How are various lines of Lyman series formed? Explain on the basis of Bohr’s theory.

State how a p-type semiconductor will be obtained from a pure crystal of a semiconductor.

Explain the following term:

Extrinsic semiconductor

If the radius of first electron orbit in hydrogen atom be r then the radius of the fourth orbit ill be ______.

The energy of an electron in an excited hydrogen atom is - 3.4 eV. Calculate the angular momentum of the electron according to Bohr's theory. (h = 6.626 × 10^-34 Js)

Distinguish between n-type and p-type semiconductors.

Using Bohr's postulates derive the expression for the radius of n^th orbit of the electron.

Ratio of longest to shortest wavelength in Balmer series is ______.

With an increase in the temperature, the electrical conductivity of a semiconductor ______.

What type of semiconductor is obtained when a crystal of silicon is doped with a trivalent element?

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.

The majority charge carriers in a P-type semiconductor are ______.

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.

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 ______.

A rectangular loop of area 5m2, has 50 turns and carries a current of 1A. It is hold in a uniform magnetic field of 0.1T, at an angle of 30°. Calculate the torque experienced by the coil.