83 free MCQs on Dual Nature of Radiation and Matter, each with its own worked answer and explanation. Photoelectric effect, de Broglie waves, Bohr's model, atomic spectra.
Take the timed Dual Nature of Radiation and Matter chapterwise test →83 practice questions on Dual Nature of Radiation and Matter, sorted Easy → Hard. Try each one first, then open its answer page for the worked explanation. Want the full theory first? Read the Dual Nature of Radiation and Matter notes.
In the photoelectric setup, light striking the metal plate ejects electrons that cross the evacuated tube to the collector, producing a measurable current on the ammeter.
Q1.
A metal surface is illuminated with light of frequency above its threshold frequency. If the intensity is increased while frequency remains unchanged, the maximum kinetic energy of emitted electrons:
Q2.
Two photons have frequencies ν and 3ν. What is the ratio of their momenta?
Q3.
An electron and a proton have the same de Broglie wavelength. Which quantity must be the same for both?
Q4.
In a photoelectric experiment, the stopping potential is zero when the incident light has:
Q5.
For a photon, which relation between energy E and momentum p is correct in vacuum?
Q6.
The photoelectric effect demonstrates that light has:
Q7.
The energy of a photon with frequency f (h = Planck's constant) is:
Q8.
Work function of a metal is the minimum energy needed to:
Q9.
Threshold frequency in photoelectric effect is the frequency below which:
Q10.
Stopping potential in photoelectric effect is the voltage needed to:
Q11.
De Broglie wavelength of a particle of momentum p:
Q12.
In Bohr's model, electrons occupy:
Q13.
Planck's constant h has the value:
Q14.
Increasing intensity of light in photoelectric effect increases:
Q15.
Thomson's atomic model is called:
Q16.
Photon has mass:
Q17.
Compton effect shows that:
Q18.
Davisson-Germer experiment confirmed:
Q19.
Light can behave both as a wave and as a:
Q20.
A quantum (packet) of light energy is called a:
Q21.
The photoelectric effect is the emission of ___ when light strikes a metal surface:
Q22.
The energy of a photon is directly proportional to its:
Q23.
The photoelectric effect was successfully explained by:
Q24.
A photon has a rest mass of:
Q25.
Increasing the intensity of the incident light increases the number of emitted:
Q26.
A 100 W sodium lamp emits light of wavelength 589 nm. Approximately how many photons does it emit per second? Take hc = 1240 eV nm and 1 eV = 1.6 × 10<sup>-19</sup> J.
Q27.
An electron and a proton are moving with equal kinetic energies. What is the ratio of their de Broglie wavelengths, λ<sub>e</sub>/λ<sub>p</sub>?
Q28.
A metal has work function 2.48 eV. What is its threshold wavelength? Take hc = 1240 eV nm.
Q29.
Light of wavelength 400 nm falls on a metal with work function 2.0 eV. Taking hc = 1240 eV nm, what is the stopping potential?
Q30.
An electron has de Broglie wavelength 0.20 nm. If its momentum is increased by 25%, what is its new wavelength?
Q31.
De Broglie wavelength of a particle with momentum p is lambda =
Q32.
In the photoelectric effect, stopping potential depends on:
Q33.
The work function of a metal is 2 eV. Threshold frequency (h = 6.6×10⁻³⁴ J·s) is approx:
Q35.
The energy of the electron in nth orbit of hydrogen: En =
Q36.
Heisenberg uncertainty principle: Delta_x × Delta_p ≥
Q37.
X-rays are produced when:
Q38.
If wavelength of electron = wavelength of photon, which has more energy?
Q39.
The first emission line in Balmer series corresponds to transition:
Q40.
Kinetic energy of emitted photoelectron when light of frequency f hits metal:
Q41.
Compton scattering: a photon scatters from an electron. The scattered photon has:
Q42.
Ionization energy of hydrogen from ground state:
Q43.
The wavelength of matter waves decreases when:
Q44.
Bohr model explains only the spectrum of:
Q45.
The energy of a photon of frequency ν is given by:
Q46.
The minimum frequency of light needed to eject electrons from a metal is the ___ frequency:
Q47.
The minimum energy required to free an electron from a metal surface is called the:
Q48.
The de Broglie wavelength of a particle of momentum p is:
Q49.
The stopping potential in the photoelectric effect depends on the ___ of the incident light:
Q50.
Below the threshold frequency, no electrons are emitted no matter how great the light’s:
Q51.
Two metals A and B are illuminated by the same monochromatic light. Their stopping potentials are 1.2 V and 0.7 V respectively. What is the difference between their work functions?
Q52.
An electron and a proton are accelerated through the same potential difference. What is the ratio of their de Broglie wavelengths, λ<sub>e</sub>/λ<sub>p</sub>?
Q53.
A photon undergoes Compton scattering through an angle of 90°. What is the increase in its wavelength? Take h/(m<sub>e</sub>c) = 2.43 pm.
Q54.
A metal has threshold frequency 5.0 × 10<sup>14</sup> Hz. It is illuminated with light of frequency 8.0 × 10<sup>14</sup> Hz. If the incident frequency is changed to 1.1 × 10<sup>15</sup> Hz, by what factor does the maximum kinetic energy increase? Assume the work function remains unchanged.
Q55.
An electron and a photon have the same momentum. If the photon has energy E, what is the kinetic energy of the electron in the non-relativistic limit?
Q56.
Moseley law for characteristic X-ray frequency: sqrt(f) ∝
Q57.
The quantum numbers (n, l, ml, ms) for the outermost electron of Na (Z=11):
Q58.
The minimum wavelength of X-rays produced by electrons accelerated through potential V is:
Q59.
In Compton scattering, the Compton wavelength shift is given by:
Q60.
The angular momentum of an electron in s orbital is:
Q61.
The cutoff frequency (threshold) in photoelectric effect for a metal with work function phi:
Q62.
The ground state wavefunction of hydrogen: psi ∝ e<sup>-r/a₀</sup>. Probability density peaks at:
Q63.
Electron affinity differs from work function because:
Q64.
Photo current in photoelectric effect is proportional to:
Q65.
Electron spin quantum number ms can only be:
Q66.
Pauli exclusion principle states that:
Q67.
Einstein’s photoelectric equation is KE_max = hν minus the:
Q68.
The de Broglie (matter) wavelength is appreciable only for particles of very ___ mass:
Q69.
The photoelectric effect provides direct evidence for the ___ nature of light:
Q70.
A photon of wavelength λ carries a momentum of:
Q71.
If the frequency of the incident light is increased above threshold, the maximum kinetic energy of the photoelectrons:
Q72.
The work function of a metal determines its ___ frequency:
Q73.
An electron accelerated through a potential difference V has a de Broglie wavelength proportional to:
Q74.
The Davisson–Germer experiment confirmed the ___ nature of electrons:
Q75.
Above the threshold frequency, the photoelectric current is proportional to the ___ of the incident light:
Q76.
Light of photon energy 5 eV falls on a metal of work function 2 eV. The maximum kinetic energy of the emitted photoelectrons is:
Q77.
If the incident light frequency is below the threshold frequency of a metal, then increasing the intensity results in:
Q78.
The de Broglie wavelength of a particle is inversely proportional to its momentum. If the momentum is doubled, the wavelength:
Q79.
In the photoelectric effect, the stopping potential is:
Q80.
An electron accelerated through a potential difference of 100 V has a de Broglie wavelength of about:
Q81.
The energy of a photon of wavelength 500 nm (using hc = 1240 eV·nm) is:
Q82.
Increasing the intensity of incident light (frequency unchanged, above threshold) in the photoelectric effect results in:
Q83.
A photon has wavelength 6.6×10⁻⁷ m (h = 6.6×10⁻³⁴ J·s). Its momentum is:
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