Selected MCQ

Current Question
The Planck constant has dimensions of:
  • A. Energy
  • B. Momentum
  • C. Action
  • D. Force
Correct Answer: C
Explanation:
Planck constant has units of energy × time (action).
Related Question 1
Which constant defines thermal energy scale?
  • A. Planck constant
  • B. Boltzmann constant
  • C. Avogadro number
  • D. Gas constant
Correct Answer: B
Explanation:
(k_B) relates temperature to energy.
Related Question 2
Which thermodynamic quantity remains constant in adiabatic process?
  • A. Temperature
  • B. Pressure
  • C. Entropy (reversible case)
  • D. Volume
Correct Answer: C
Explanation:
Reversible adiabatic process is isentropic.
Related Question 3
The cosmological constant is associated with:
  • A. Gravity weakening
  • B. Dark energy
  • C. Dark matter
  • D. Nuclear force
Correct Answer: B
Explanation:
Cosmological constant models accelerated expansion.
Related Question 4
In thermodynamics, the Helmholtz free energy is minimized at constant:
  • A. Pressure and temperature
  • B. Volume and temperature
  • C. Volume and entropy
  • D. Pressure and entropy
Correct Answer: B
Explanation:
Helmholtz free energy applies to constant T and V systems.
Related Question 5
Which constant relates energy and frequency?
  • A. Boltzmann constant
  • B. Planck constant
  • C. Avogadro number
  • D. Gas constant
Correct Answer: B
Explanation:
(E = h\nu).