Question

Which of the following is not a characteristic of Planck’s quantum theory of radiation?
(A)Radiations are associated with energy
(B)Magnitude of energy associated with a quantum is equal to hv
(C)Radiation energy is neither emitted or absorbed continuously
(D)A body can emit less or more than a quantum of energy

Answer 1

Hint: Planck's quantum theory of radiation has certain statements, consider those statements and check whether the options are correct according to that.

Complete step by step answer:
According to Planck’s quantum theory, the smallest amount of energy that can be emitted or absorbed in the form of electromagnetic radiation is known as quantum. The energy of the radiation absorbed or emitted is directly proportional to the frequency ($v$) and inversely proportional to wavelength ($\lambda $)
$E=hv=\dfrac{hc}{\lambda }$
$h$ is Planck’s constant which is equal to 6.626×10-27 erg–sec or 6.626×10-34 J–sec.

When a black body is heated, it emits thermal radiation of various wavelengths or frequencies. To elucidate these radiations, Planck suggests a theory referred to as Planck’s scientific theory. The most points of scientific theory are:
(i) Substances radiate or absorb energy discontinuously within the sort of small packets or bundles of energy.
(ii) The smallest packet of energy is named quantum, within the case of sunshine , the quantum is understood as a photon.
(iii) The energy of a quantum is directly proportional to the frequency of the radiation.
$E=hv$ whereis the frequency of radiation and is $h$ Planck’s constant.
(iv) A body can radiate or absorb energy in integer multiples of a quantum.

Options A: Radiations are associated with energy. This is not the characteristic of Planck’s quantum theory of radiation. Hence option A is the right answer.
Options B: Magnitude of energy associated with a quantum is proportional to the frequency ($v$) and inversely proportional to wavelength ($\lambda $). $E=hv=\dfrac{hc}{\lambda} $
 Hence, option b is the characteristic of Planck’s quantum theory of radiation.
Option C: Radiation energy is neither emitted or absorbed continuously but discontinuously in the form of small packets called quanta. Hence, option c is the characteristic of Planck’s quantum theory of radiation.
Option D: A body can absorb or radiate energy in integer multiples of a quantum $hv$, $2hv$, $3hv$ ........ $nhv$where n is that the positive integer. Hence, option d is the characteristic of Planck’s quantum theory of radiation.

Hence, option (A) is not the characteristic of Planck's quantum theory of radiation.

 Note:
-If frequency is bigger than threshold frequency: Then ejection occurs and also, kinetic energy is imparted to the ejected electron.
-If frequency is adequate to threshold frequency, then only ejection occurs.
-If frequency is a smaller amount than threshold frequency, then no ejection occurs and no kinetic energy is imparted.