Selected MCQ

Current Question
Which statement about simple harmonic motion is correct?
  • A. Acceleration is proportional to displacement and in the same direction
  • B. Velocity is maximum at extreme position
  • C. Total energy varies sinusoidally
  • D. Acceleration is proportional to displacement and opposite in direction
Correct Answer: D
Explanation:
SHM requires a restoring acceleration opposite to displacement.
Related Question 1
Which statement about radiometric dating is correct?
  • A. It depends on constant atmospheric pressure
  • B. It uses known decay rates of radioactive isotopes
  • C. It works only on sedimentary rocks directly
  • D. It requires fossils in all samples
Correct Answer: B
Explanation:
Isotopic parent-daughter ratios and decay constants allow age estimation.
Related Question 2
Which statement is correct for a buffer solution?
  • A. It resists all pH changes regardless of added amount
  • B. It contains a strong acid and strong base in equal amounts
  • C. It resists pH change upon small addition of acid or base
  • D. Its pH is always 7
Correct Answer: C
Explanation:
Buffers work through conjugate acid-base pairs that neutralize small perturbations.
Related Question 3
Which statement about hydrogen bonding is correct?
  • A. It occurs only in hydrocarbons
  • B. It requires hydrogen bonded to highly electronegative atoms such as N, O, or F
  • C. It is weaker than all London forces
  • D. It is a covalent bond between two molecules
Correct Answer: B
Explanation:
Strong intermolecular hydrogen bonding needs a polarized H attached to N, O, or F.
Related Question 4
Which statement about electron affinity is generally correct?
  • A. It becomes less exothermic across a period
  • B. Noble gases usually have strongly negative values
  • C. Halogens tend to have highly exothermic electron affinities
  • D. It is identical to ionization energy
Correct Answer: C
Explanation:
Halogens readily gain one electron to complete their valence shell.
Related Question 5
Which statement about entropy is correct for an isolated system?
  • A. It always decreases
  • B. It remains zero
  • C. It cannot decrease in spontaneous processes
  • D. It depends only on pressure
Correct Answer: C
Explanation:
The second law states entropy of an isolated system does not spontaneously decrease.