Modern Physics and Electronic Devices — Practice

Question 1

In the photoelectric effect, if the intensity of the incident light is increased (frequency unchanged), then

Accepted Answer

A

Question 2

Light of photon energy 5 eV strikes a metal of work function 2 eV. The maximum kinetic energy of the emitted electrons is

Accepted Answer

A

Question 3

The energy of a photon of wavelength 620 nm is approximately

Accepted Answer

A

Question 4

The momentum of a photon of wavelength λ is

Accepted Answer

A

Question 5

If the speed of a particle is doubled (mass unchanged), its de Broglie wavelength becomes

Accepted Answer

A

Question 6

The energy of the electron in the ground state (n = 1) of the hydrogen atom is

Accepted Answer

A

Question 7

The energy required to ionise a hydrogen atom from its ground state is

Accepted Answer

A

Question 8

If the radius of the first Bohr orbit of hydrogen is 0.53 Å, the radius of the second orbit (n = 2) is

Accepted Answer

A

Question 9

The energy released when an electron in hydrogen falls from n = 2 to n = 1 is

Accepted Answer

A

Question 10

The series of hydrogen spectral lines that lies in the visible region is the

Accepted Answer

A

Question 11

After 2 half-lives, the fraction of a radioactive sample remaining undecayed is

Accepted Answer

A

Question 12

When a nucleus emits an alpha particle, its mass number A and atomic number Z change by

Accepted Answer

A

Question 13

The binding energy per nucleon is maximum for nuclei near

Accepted Answer

A

Question 14

An n-type semiconductor is made by doping silicon with a

Accepted Answer

A

Question 15

A p–n junction diode conducts appreciably when it is

Accepted Answer

A

Practice — Modern Physics and Electronic Devices