Practice Physics MCQs for PPSC Assistant (BS-16) Everyday Science — topic-wise sets with solved answers.
Q1. Sound travels fastest in:
Answer: Solid
Explanation: Solid is the scientifically accurate choice. The concept tested here is core everyday science for MDCAT, ECAT, and general ability papers.
Q2. Fiber optics are primarily used in which field?
Answer: Telecommunication
Explanation: Telecommunication is the scientifically accurate choice. The concept tested here is core everyday science for MDCAT, ECAT, and general ability papers.
Q3. An ice mass that covers more than 50,000 square kilometers of land area is classified as an:
Answer: Ice sheet
Explanation: An ice sheet is defined as a continental glacier covering more than 50,000 km²; the two existing ice sheets are in Antarctica and Greenland.
Q4. The instrument used to measure the velocity of wind is a barometer.
Answer: Wrong
Explanation: Wind velocity is measured by an anemometer, not a barometer; a barometer measures atmospheric pressure.
Q5. In a fission nuclear reaction, a heavy nucleus breaks up into smaller nuclei. In contrast, when two or more lighter nuclei fuse to form a heavier nucleus, the reaction is called a:
Answer: Fusion nuclear reaction
Explanation: Nuclear fusion is the reaction in which two or more light atomic nuclei combine to form a heavier nucleus, releasing enormous energy - the process that powers the Sun.
Q6. Sound travels faster in iron than in air.
Answer: Right
Explanation: Sound travels at approximately 5,120 m/s in iron compared to only 343 m/s in air, because solids have stronger intermolecular bonds that transmit vibrations more efficiently.
Q7. The speed of sound is maximum through which of the following?
Answer: Glass
Explanation: Sound travels fastest through glass among the listed options because glass is a rigid solid with high elastic modulus; sound speed in glass is about 5,640 m/s.
Q8. Which mirror is used in the headlights of cars?
Answer: Concave
Explanation: Concave is the scientifically accurate choice. The concept tested here is core everyday science for MDCAT, ECAT, and general ability papers.
Q9. ______ is an instrument for measuring a small electric current.
Answer: Galvanometer
Explanation: A galvanometer is a sensitive electromagnetic instrument used to detect and measure very small electric currents by deflecting a needle proportional to current flow.
Q10. Though the temperature inside a lighted electric bulb is around 2700°C, the filament does not burn because:
Answer: The oxygen necessary for combustion (and burning) is not available as the bulb is evacuated and filled with pure nitrogen or inert gases
Explanation: The bulb is filled with nitrogen or inert gases (like argon) instead of oxygen; without oxygen, the tungsten filament cannot undergo combustion even at temperatures exceeding 2,700°C.
Q11. In which medium does sound travel fastest?
Answer: Steel
Explanation: Sound travels fastest in steel (approximately 5,960 m/s) because the high density and elastic modulus of steel allow sound waves to propagate with minimal energy loss.
Q12. The waves used for sending signals to a satellite from a ground station are:
Answer: Microwaves
Explanation: Microwaves (GHz frequency range) are used to communicate with satellites because they can penetrate Earth's atmosphere with minimal absorption and travel in line-of-sight paths.
Q13. Sound cannot travel through a:
Answer: Vacuum
Explanation: Sound requires a material medium to travel; in a vacuum there are no molecules to carry mechanical vibrations, so sound cannot propagate.
Q14. One thousand watts of power is called:
Answer: 1.0 kilowatt
Explanation: By SI definition, 1 kilowatt (kW) equals exactly 1,000 watts; so 1,000 W = 1.0 kW.
Q15. What are the primary colors of light?
Answer: Red, blue, green
Explanation: The three primary colors of light (additive color model) are red, green, and blue (RGB); combining all three at full intensity produces white light.
Q16. A plant with green leaves placed in red light will appear:
Answer: Black
Explanation: Green leaves absorb red light (not reflecting it) for photosynthesis, so under red light the leaves appear black because they absorb the red light and have no other color to reflect.
Q17. What is the SI unit of heat?
Answer: Joule
Explanation: In the SI system, the joule (J) is the standard unit of energy, including heat energy; one joule equals one Newton-meter or one watt-second.
Q18. A light-year measures what?
Answer: Distance
Explanation: A light-year is a unit of distance - the distance light travels in one year (approximately 9.46 × 10¹² km) - not a unit of time despite containing the word "year."
Q19. All forms of energy that we use are ultimately transformed into:
Answer: Heat energy
Explanation: By the second law of thermodynamics, all energy conversions ultimately produce heat as a byproduct; heat is the final, degraded form into which all useful energy is eventually transformed.
Q20. Einstein's famous equation, which states that mass and energy are interchangeable, is:
Answer: E = mc²
Explanation: Einstein's mass-energy equivalence equation E = mc² states that energy equals mass multiplied by the square of the speed of light, showing mass and energy are interchangeable.
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