SET 11

🎯 Objectives: TOWARD NECTA Physics - Set 11 Questions and Answers

SET 11: NECTA Form Four Physics Conceptual Questions and Answers

  1. What is meant by the term ‘inertia’?
    Answer: Inertia is the property of a body to resist any change in its state of rest or uniform motion.
    Example: A stationary book remains at rest until pushed.
  2. Explain how a thermocouple works.
    Answer: It produces a voltage when there is a temperature difference between two junctions of different metals.
    Example: Used in temperature sensors.
  3. What is the difference between elastic and plastic deformation?
    Answer: Elastic deformation is temporary and reversible; plastic deformation is permanent.
    Example: Rubber band stretches elastically; clay molds plastically.
  4. Why does a concave lens always produce a virtual image?
    Answer: Because it diverges light rays which never actually meet, forming a virtual image.
    Example: Used in corrective glasses for short-sightedness.
  5. State Boyle’s Law.
    Answer: For a fixed amount of gas at constant temperature, pressure is inversely proportional to volume.
    Example: Compressing air in a syringe.
  6. What causes electrical resistance in a conductor?
    Answer: Collisions between moving electrons and atoms in the conductor.
    Example: Copper wire heats up when current flows.
  7. Explain the principle of superposition of waves.
    Answer: When two or more waves meet, the resultant displacement is the algebraic sum of individual displacements.
    Example: Interference patterns from water waves.
  8. Why is light slower in glass than in air?
    Answer: Glass is denser, causing light to interact more with atoms, slowing it down.
    Example: Refraction occurs at glass-air boundary.
  9. What is meant by the term ‘terminal velocity’?
    Answer: The constant speed reached when the force of gravity is balanced by air resistance.
    Example: A skydiver falling at steady speed.
  10. Why do metals conduct heat better than non-metals?
    Answer: Metals have free electrons that transfer energy quickly.
    Example: Metal cooking pots heat up quickly.
  11. What is meant by electric current?
    Answer: The flow of electric charge (usually electrons) through a conductor.
    Example: Current powering a light bulb.
  12. Describe how a capacitor works.
    Answer: It stores electrical energy in an electric field between two plates.
    Example: Used in camera flashes.
  13. Why does a metal wire stretch when a force is applied?
    Answer: The force pulls atoms apart, elongating the wire.
    Example: Wires elongate under heavy loads.
  14. What is the principle behind a hydraulic brake system?
    Answer: Pressure applied on a small piston is transmitted through a fluid to a larger piston, multiplying force.
    Example: Car brake systems.
  15. Explain why the sky appears blue.
    Answer: Shorter blue wavelengths scatter more than other colors in the atmosphere.
    Example: Clear daytime skies are blue.
  16. What is the relationship between wavelength, frequency, and speed of a wave?
    Answer: Speed = wavelength × frequency.
    Example: Radio waves with longer wavelengths have lower frequency.
  17. Why do some materials become magnets when placed in a magnetic field?
    Answer: Their magnetic domains align in the direction of the field.
    Example: Iron becoming magnetized.
  18. What causes the Doppler effect?
    Answer: Change in frequency or pitch of a wave due to relative motion between source and observer.
    Example: Ambulance siren pitch changes as it passes.
  19. Define electric potential difference (voltage).
    Answer: Work done to move a unit charge between two points.
    Example: Battery voltage.
  20. Why does the mercury level in a thermometer rise when heated?
    Answer: Mercury expands with temperature, increasing its volume.
    Example: Measuring body temperature.

📖 Reference Book: N/A

📄 Page: 11