What does Planck’s black body radiation theory describe?
a) The emission of light from black holes
b) The emission of electromagnetic radiation from a perfect absorber and emitter of radiation
c) The reflection of light from a black surface
d) The scattering of light by a black surface
Correct answer: b) The emission of electromagnetic radiation from a perfect absorber and emitter of radiation
Description: Planck’s black body radiation theory explains the radiation emitted by a perfect absorber and emitter of radiation, known as a black body.
According to Planck’s theory, the energy of emitted radiation is quantized into discrete units called:
a) Quanta
b) Photons
c) Protons
d) Electrons
Correct answer: b) Photons
Description: Planck introduced the concept of quantized energy in the form of photons to explain the spectrum of black body radiation.
What is the relationship between the frequency (ν) and the energy (E) of a photon according to Planck’s theory?
a) E ∝ ν
b) E ∝ ν^2
c) E ∝ 1/ν
d) E ∝ 1/ν^2
Correct answer: a) E ∝ ν
Description: Planck’s theory states that the energy of a photon is directly proportional to its frequency.
Which of the following represents Planck’s black body radiation formula?
a) E = mc^2
b) E = hf
c) E = h/λ
d) E = hν
Correct answer: d) E = hν
Description: This formula represents the energy of a photon, where E is energy, h is Planck’s constant, and ν is the frequency.
What does the Wien displacement law describe?
a) The relationship between the temperature of a black body and the wavelength at which its emission spectrum peaks
b) The relationship between the temperature of a black body and the total emitted radiation
c) The relationship between the temperature of a black body and the area under its emission spectrum curve
d) The relationship between the temperature of a black body and the intensity of its emitted radiation
Correct answer: a) The relationship between the temperature of a black body and the wavelength at which its emission spectrum peaks
Description: The Wien displacement law states that the wavelength at which the emission spectrum of a black body peaks is inversely proportional to its temperature.
At what temperature does a black body radiate most of its energy in the visible spectrum?
a) 500 K
b) 1000 K
c) 3000 K
d) 5000 K
Correct answer: c) 3000 K
Description: At around 3000 K, a black body radiates most of its energy in the visible spectrum, appearing as a glowing red color.
Which law describes the distribution of energy among different wavelengths of radiation emitted by a black body at a given temperature?
a) Stefan-Boltzmann law
b) Wien displacement law
c) Planck’s law
d) Beer-Lambert law
Correct answer: c) Planck’s law
Description: Planck’s law describes the distribution of energy among different wavelengths of radiation emitted by a black body at a specific temperature.
According to Planck’s theory, what happens to the intensity of black body radiation as the temperature increases?
a) It decreases
b) It remains constant
c) It increases
d) It oscillates
Correct answer: c) It increases
Description: Planck’s theory predicts that the intensity of black body radiation increases with increasing temperature.
What is the significance of Planck’s constant (h) in black body radiation?
a) It represents the maximum wavelength of emitted radiation
b) It represents the minimum wavelength of emitted radiation
c) It relates the energy of a photon to its frequency
d) It determines the speed of light
Correct answer: c) It relates the energy of a photon to its frequency
Description: Planck’s constant relates the energy of a photon to its frequency, providing a fundamental constant in the description of black body radiation.
Which of the following is NOT a consequence of Planck’s black body radiation theory?
a) Explanation of the ultraviolet catastrophe
b) Emergence of the concept of quantized energy
c) Development of quantum mechanics
d) Explanation of the photoelectric effect
Correct answer: d) Explanation of the photoelectric effect
Description: While Planck’s theory contributed to the development of quantum mechanics, it did not directly explain the photoelectric effect, which was later explained by Einstein.
What does the term “black body” refer to in the context of Planck’s radiation theory?
a) A body that absorbs all incident radiation and reflects none
b) A body that emits radiation at all wavelengths
c) A body that reflects all incident radiation and absorbs none
d) A body that emits and absorbs radiation at only specific wavelengths
Correct answer: a) A body that absorbs all incident radiation and reflects none
Description: A black body is an idealized physical body that absorbs all incident electromagnetic radiation, reflecting none.
Which of the following is a key assumption in Planck’s black body radiation theory?
a) Radiation is continuous
b) Radiation is quantized
c) Radiation is always emitted at the same intensity
d) Radiation is unaffected by temperature
Correct answer: b) Radiation is quantized
Description: Planck introduced the assumption of quantized energy to explain the observed spectrum of black body radiation.
At what temperature does a black body emit radiation with the maximum intensity?
a) 0 K
b) 100 K
c) 5000 K
d) There is no specific temperature
Correct answer: c) 5000 K
Description: A black body emits radiation with the maximum intensity at around 5000 K.
Which of the following statements best describes the relationship between the wavelength and intensity of black body radiation?
a) As wavelength increases, intensity decreases
b) As wavelength decreases, intensity increases
c) Wavelength and intensity are not related
d) Intensity decreases with increasing temperature
Correct answer: b) As wavelength decreases, intensity increases
Description: This relationship is described by Wien’s displacement law, where shorter wavelengths correspond to higher intensities.
What phenomenon does Planck’s black body radiation theory successfully explain?
a) The photoelectric effect
b) The behavior of electrons in atoms
c) The ultraviolet catastrophe
d) The interference of light waves
Correct answer: c) The ultraviolet catastrophe
Description: Planck’s theory successfully explains the
What term describes the phenomenon where classical physics fails to correctly predict the intensity of black body radiation at short wavelengths?
a) Ultraviolet paradox
b) Infrared anomaly
c) Ultraviolet catastrophe
d) Black body enigma
Correct answer: c) Ultraviolet catastrophe
Description: The ultraviolet catastrophe refers to the discrepancy between classical physics predictions and experimental observations of black body radiation intensity at short wavelengths.
Which of the following scientists first proposed the concept of quantized energy to explain black body radiation?
a) Albert Einstein
b) Max Planck
c) Niels Bohr
d) Werner Heisenberg
Correct answer: b) Max Planck
Description: Max Planck introduced the idea of quantized energy to explain the spectrum of black body radiation, which was a revolutionary concept in physics.
According to Planck’s black body radiation theory, what property of a black body changes with temperature?
a) The rate of radiation emission
b) The color of emitted light
c) The density of the body
d) The speed of light within the body
Correct answer: b) The color of emitted light
Description: As the temperature of a black body changes, the color of the emitted light shifts, following a specific pattern described by Wien’s displacement law.
Which law states that the total energy radiated per unit surface area of a black body is directly proportional to the fourth power of its absolute temperature?
a) Planck’s law
b) Wien’s law
c) Stefan-Boltzmann law
d) Beer-Lambert law
Correct answer: c) Stefan-Boltzmann law
Description: The Stefan-Boltzmann law describes the total energy radiated by a black body, showing how it increases rapidly with temperature.
What effect did Planck’s black body radiation theory have on classical physics?
a) It confirmed the predictions of classical physics
b) It had no impact on classical physics
c) It challenged and ultimately led to the development of quantum mechanics
d) It disproved the laws of thermodynamics
Correct answer: c) It challenged and ultimately led to the development of quantum mechanics
Description: Planck’s theory challenged classical physics and paved the way for the development of quantum mechanics, which revolutionized our understanding of the microscopic world.
Which of the following quantities is not represented by a constant in Planck’s black body radiation formula?
a) Speed of light (c)
b) Planck’s constant (h)
c) Frequency (ν)
d) Wavelength (λ)
Correct answer: d) Wavelength (λ)
Description: Wavelength is a variable in Planck’s formula, not a constant. The constants are speed of light (c) and Planck’s constant (h).
What is the name of the phenomenon where a black body emits less radiation at specific wavelengths than predicted by classical physics?
a) Infrared anomaly
b) Ultraviolet catastrophe
c) Black body enigma
d) Wien’s effect
Correct answer: a) Infrared anomaly
Description: The infrared anomaly refers to the discrepancy between classical physics predictions and observed radiation intensities at specific infrared wavelengths.
What does the term “Planck’s constant” represent in the context of black body radiation?
a) The maximum possible energy of a photon
b) The minimum possible energy of a photon
c) The proportionality constant relating energy and frequency of a photon
d) The proportionality constant relating energy and wavelength of a photon
Correct answer: c) The proportionality constant relating energy and frequency of a photon
Description: Planck’s constant (h) relates the energy of a photon to its frequency, as described by Planck’s formula for black body radiation.
Which of the following statements best describes the significance of Planck’s black body radiation theory?
a) It reconciled classical physics with quantum mechanics
b) It disproved the laws of thermodynamics
c) It explained the behavior of light in vacuum
d) It predicted the existence of black holes
Correct answer: a) It reconciled classical physics with quantum mechanics
Description: Planck’s theory played a crucial role in reconciling classical physics with the emerging field of quantum mechanics, laying the foundation for modern physics.
What is the name of the theoretical construct that absorbs all incident electromagnetic radiation without reflecting or transmitting any?
a) Perfect reflector
b) Black hole
c) Ideal absorber or black body
d) Photon emitter
Correct answer: c) Ideal absorber or black body
Description: A black body is an idealized theoretical construct that absorbs all incident electromagnetic radiation without reflecting or transmitting any, making it an ideal absorber.