Quantum Physics

Which of the following statement is not a characteristic of photoelectric effect?

• Intensity of light affects the energy of photoelectron

• The greater the frequency of photons, the greater the maximum kinetic energy of photoelectrons

• The emission of electrons from the surface of a metal occurs instantaneously

• The minimum frequency known as threshold frequency is required to emit the electrons.

The maximum wavelength able to release electron from sodium surface is 650 nm.
Determine the maximum kinetic energy of electron ejected from the sodium surface if light of wavelength 436 nm is incidental on its surface in vacuum.

• 1.50 x 10^(-18) J

• 1.50 x 10^(-19) J

• 3.06 x 10^(-19) J

• 4.56 x 10^(-19) J

The minimum frequency able to release electron from sodium surface is 4.615 x 10^(14) Hz.
Determine the maximum kinetic energy of electron ejected from the sodium surface if light of frequency

6.880 x 10^(14) Hz is incidental on its surface in vacuum.

• 1.50 x 10^(-18) J

• 1.50 x 10^(-19) J

• 3.06 x 10^(-19) J

• 4.56 x 10^(-19) J

Given that the photon energy of red light is 2.93 x 10^(-19) J and the work function of lithium metal is 2.5eV.

What would happen if the red light shone on the lithium metal surface ?

[ 1eV = 1.60 x 10^-19 J ]

• The photoelectric effect does not occur

• The electrons escape the metal surface instantaneously

• The maximum kinetic energy of photoelectron increases

• The threshold frequency is smaller than the light frequency

The diagram shows the change in the spectrum of black body radiation with temperature.

Which comparison is correct ?

• T1 > T2 > T3

• T2 > T1 > T3

• T2 >T3 > T1

• T3 > T2 > T1