Question # 1

Light of frequency 2 times the threshold frequency is incident on the metalsurface. Ifthe frequency is by quartered and intensity is doubled, the photoelectric becomes

Choose an answer

Quadrupled

Zero

Doubled

Halved

Light elements do not emit X-rays because

Choose an answer

Electrons in it have high binding energy

These materials are non- material

There is a small difference in their energy shells

Electrons in it require very large energy to remove from these materials

What is the momentum of a photon of light of wavelength 500 nm in kgm/s:

Choose an answer

1.32 × 10−21

1.32 × 10−23

1.32 × 10−25

1.32 × 10−27

electrons from the surface of a metal when:

Choose an answer

It is heated to a high temperature

Radiation of suitable wavelength falls on it

Electrons of suitable velocity strike it

It is placed in a strong electric field

Which one is the correct express of de-Broglie equation for the length of atoms of mass m at temp? T(k=Boltzmann’s constant):

Choose an answer

Monochromatic light of wavelength 300 nm is incident normally on a surface of area 4 cm2.

If the intensity of light is 150 mW/m2; the rate at which photon strike the surface:

Choose an answer

2.53 × 1019

7.5 × 1019

9.1 × 1013

2.53 × 1013

The hydrogen atoms are excited to the stationary state designated by the principal quantum number n=4, the number of maximum spectral lines are observe:

Choose an answer

2

3

4

6

In electron microscope, we use high speed electrons because them

Choose an answer

Penetration power is higher

Wavelength is smaller

Frequency is smaller

K.E is smaller

The de-Broglie wavelength of the particle of mass m and energy E is:

Choose an answer

ℎ

𝜆 = ℎ√2𝑚𝐸

𝜆 = 1

For X-rays which of the following is not correct:

Choose an answer

Cause of ionization in air when they pass through it

Can be deflected by electric and magnetic fields

Can be used to detect flaws in metal casting

Travel with the speed of light

When ultraviolet rays are incident in metal plate, then photoelectric effect does not occur. It occurs by the incidence of:

Choose an answer

x-rays

Infrared rays

Radio wave

Greenhouse effect

In which region of the electromagnetic spectrum does the Lyman series of hydrogen atom lie?

Choose an answer

Infrared

Visible

Ultraviolet

X-rays

The Balmer series is found in the spectrum of:

Choose an answer

Hydrogen

Nitrogen

Oxygen

All

In photoelectric effect experiment, stopping potential depend upon

Choose an answer

Intensity of light

Frequency of light

Photoelectric current

Both A and B

The minimum energy required to remove an electron is called:

Choose an answer

Stopping potential

Work function

Kinetic energy

None of these

A photo cell receives light from a source at 50 cm away and produces 40mAcurrent inthe circuit. When the same source at is at distance 1 m from photo cell,current in the circuit will be

Choose an answer

20 mA

80mA

60 mA

10 mA

Which of the following is not true?

Choose an answer

The Lyman series is a continuous spectrum

The Ballmer series is a line spectrum in the visible region

The Paschen series is a line spectrum in the infrared region

The spectral series formula can be derived from Rutherford’s model of the hydrogen atom 18. The photoelectric effect is the ejection of

Intensity of light from a point source at the edge of unit sphere will be:

Choose an answer

𝑃

P(4π)

4𝜋

Figure represents a graph of kinetic energy (K) of the photoelectrons (in eV) and frequency (v) for a metal used as cathode in photoelectric experiment. The work function of metal is:

Choose an answer

1 eV

2 eV

1.5 eV

3 eV

Maximum speed of electrons in X-rays tube which is producing X-rays photons of frequency f is

More Classes

Other Links

MDCAT Physics Chapter 12 Atomic spectra Induction Online Test MCQs With Answers

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer