Free Planck's Quantum Theory MCQs with Answers

• A. continuously in any amount
• B. in discrete packets whose energy is proportional to frequency
• C. only as heat
• D. in packets whose energy is proportional to wavelength

Explanation: Planck proposed that radiation is emitted in quanta of energy E equal to h times the frequency, where h is Planck's constant.

• A. 6.63 times 10 to the minus 34 J s
• B. 3.0 times 10 to the 8 J s
• C. 1.6 times 10 to the minus 19 J s
• D. 9.1 times 10 to the minus 31 J s

Explanation: The extreme smallness of Planck's constant is why quantisation is invisible in everyday life and only matters at atomic scale.

• A. wavelength
• B. frequency
• C. speed
• D. amplitude

Explanation: Energy equals Planck's constant multiplied by frequency, so higher frequency means more energetic quanta, and since frequency and…

• A. 6.6262x10-30 J.sec
• B. 6.6262x10-32 J.sec
• C. 6.6262x10+34 J.sec
• D. 6.6262x10-34 J.sec

Explanation: Planck's constant is 6.626 times 10 to the minus 34 joule seconds, and its extreme smallness is why quantisation is invisible in everyday…

• A. reflection
• B. interference
• C. diffraction
• D. refraction

Explanation: When light enters a prism, it changes speed at the boundary between air and glass and bends, which is refraction.

• A. Ultra voilet
• B. Gamma rays
• C. Infrared
• D. All of these

Explanation: The Earth receives much of the Sun’s incoming energy in visible and shorter-wavelength radiation, but its cooler surface emits mainly…

• A. 159.6kJ
• B. 135.5 KJ
• C. 110.5 KJ
• D. 80.4 KJ

Explanation: The energy of one photon is E = hν, so the energy of one mole is E = NAhν = (6.022 x 10^23 mol-1)(6.626 x 10^-34 J s)(4 x 10^14 s-1) =…

• A. Spectrophotometer method
• B. Dilatometric method
• C. Optical relation method
• D. Refractometric method

Explanation: A spectrophotometer measures how much radiation a substance absorbs at selected wavelengths, usually by comparing incident and transmitted…

• A. Moseley
• B. Davisson and Germer
• C. Einstein
• D. Roentgen

Explanation: Davisson and Germer verified the wave nature and de Broglie wavelength of electrons by observing electron diffraction from a nickel…

• A. Is independent of wavelength
• B. Depends upon source
• C. Depends upon its frequency
• D. Equals to the square of amplitude

Explanation: In a vacuum, every photon travels at the constant speed of light, c, regardless of its wavelength or frequency.

• A. de-Broglie duel nature of matter
• B. Bohrs model
• C. Plancks Quantum theory
• D. Rutherfords atomic model

Explanation: Planck's quantum theory gives the photon-energy relation E = hν, where h is Planck's constant and ν is frequency.

• A. Shorter wavelength
• B. Larger wavelength
• C. X-ray not produced
• D. All are possible

Explanation: According to Moseley's relationship, increasing atomic number increases the frequency of characteristic X-rays.

• A. Beta-rays
• B. Alpha-rays
• C. X-rays
• D. Gamma-rays

Explanation: When high-speed electrons strike a heavy-metal target, they are suddenly decelerated and emit X-rays, including bremsstrahlung and…

• A. 2-times
• B. 3-times
• C. 4-times
• D. 6 times

Explanation: According to the Bohr model, the radius of an orbit is proportional to n2, so r2/r1 = 2²/1² = 4.

• A. In continuous manner
• B. Discontinuous manner
• C. Simultaneously
• D. In the form of heat

Explanation: Planck proposed that energy is emitted or absorbed in definite packets called quanta, so the exchange is discontinuous rather than…

• A. 0.33 nm
• B. 0.34 nm
• C. 0.35 nm
• D. 0.36 nm

Explanation: The de Broglie wavelength is λ = h/mv = (6.626 x 10^-34 J s)/[(9.109 x 10^-31 kg)(2.188 x 10^6 m/s)] = 3.33 x 10^-10 m.

• A. E= hcv
• B. E= c/v
• C. E= cv
• D. None of these

Explanation: Planck's quantum theory is fundamentally characterized by the equation E = hv, where E is the energy of a photon, h is Planck's constant…

• A. Photon
• B. Wavelength
• C. Frequency
• D. Velocity

Explanation: According to E = hf, it can be seen that 'E' (energy of quantum) is directly proportional to 'f' (frequency).

• A. 6.62 x 10^-34Js
• B. 6.02 x 10^-34Js
• C. 6.62 x 10^-33Js
• D. 6.34 x 10^-34 Js

Explanation: The value of Planck's constant (h) is approximately 6.62607015 × 10-34 Joule-seconds (Js) or 4.135667696 × 10-15 electron volts-seconds…

• A. E = hc/v
• B. E = c/v
• C. E = cv
• D. None of these options are correct

Explanation: The equation for Planck's quantum theory is:E = hfwhere E is the energy of a photon, h is Planck's constant (6.626 x 10^-34…