SCIENCE FOR DESIGN EXAMINATIONS

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BASIC SCIENCE 

PHYSICS — 30 MCQs WITH EXPLORATORY ANSWERS

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1. Which of the following is NOT a source of light?

A. Sun
B. Candle
C. Moon
D. Torch

Answer: C. Moon
Explanation: The Moon looks bright but doesn’t produce its own light. It reflects sunlight. Sun, candle, and torch are luminous objects because they generate light. The Moon is non-luminous.

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2. The SI unit of force is:

A. Joule
B. Newton
C. Watt
D. Pascal

Answer: B. Newton
Explanation: Force = mass × acceleration. Newton is named after Isaac Newton.
Joule = energy, Watt = power, Pascal = pressure.

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3. When a substance changes state from solid to liquid, the process is called:

A. Condensation
B. Sublimation
C. Melting
D. Evaporation

Answer: C. Melting
Explanation: Heat is absorbed by solid → particles loosen → becomes liquid.
Condensation = gas → liquid, Evaporation = liquid → gas, Sublimation = solid → gas.

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4. Speed is defined as:

A. Distance × Time
B. Distance ÷ Time
C. Time ÷ Distance
D. Force ÷ Distance

Answer: B. Distance ÷ Time
Explanation: Speed tells how fast an object is moving.
Formula: Speed = Distance/Time.

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5. Which of the following is an example of a non-contact force?

A. Friction
B. Tension
C. Magnetic force
D. Push

Answer: C. Magnetic force
Explanation: Non-contact forces act without physical touch—gravity, electricity, magnetism.

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6. Sound cannot travel through:

A. Solids
B. Water
C. Air
D. Vacuum

Answer: D. Vacuum
Explanation: Sound needs a medium with particles. No particles → no vibration → no sound.

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7. Which type of mirror is used in car headlights?

A. Plane mirror
B. Convex mirror
C. Concave mirror
D. Cylindrical mirror

Answer: C. Concave mirror
Explanation: Concave mirrors focus light into a beam, making headlights powerful.

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8. Which of these has the highest density?

A. Ice
B. Water
C. Iron
D. Wood

Answer: C. Iron
Explanation: Density = mass per volume. Metals like iron are very dense. Ice < water because ice has a more open structure.

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9. The unit of electric current is:

A. Volt
B. Ampere
C. Ohm
D. Watt

Answer: B. Ampere
Explanation: Electric current = flow of electrons. Measured in Ampere.

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10. A rainbow is formed due to:

A. Reflection of light
B. Refraction of light
C. Dispersion of light
D. Both B and C

Answer: D. Both B and C
Explanation:
Sunlight enters raindrop → Refraction
White light splits → Dispersion
Colours form a circular arc.

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11. The image formed on the retina of the human eye is:

A. Virtual and upright
B. Real and inverted
C. Real and upright
D. Diminished only

Answer: B. Real and inverted
Explanation: Lens in eye focuses light inward → real inverted image. Brain flips it automatically.

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12. Friction always acts:

A. In the direction of motion
B. Opposite to motion
C. Perpendicular to motion
D. Randomly

Answer: B. Opposite to motion
Explanation: Friction tries to stop movement, so it opposes motion.

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13. A device used to measure temperature is:

A. Barometer
B. Hygrometer
C. Thermometer
D. Anemometer

Answer: C. Thermometer
Explanation:
Barometer = pressure
Hygrometer = humidity
Anemometer = wind speed.

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14. Which of these is the best conductor of heat?

A. Wood
B. Rubber
C. Plastic
D. Copper

Answer: D. Copper
Explanation: Metals conduct heat well because their particles are free-moving.

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15. Why does a black T-shirt feel hotter in sunlight?

A. Black reflects heat
B. Black absorbs all colours
C. Black emits cold
D. Because it is thick

Answer: B. Black absorbs all colours
Explanation: Black absorbs heat; white reflects it. That’s why black clothes feel hotter.

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16. The gravitational force of Earth acts:

A. Away from the centre
B. Toward the centre of Earth
C. Only on heavy objects
D. Only on living things

Answer: B. Toward the centre
Explanation: Gravity pulls everything towards the Earth’s centre.

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17. The ability to do work is called:

A. Power
B. Force
C. Energy
D. Momentum

Answer: C. Energy
Explanation: Without energy nothing can move or change.

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18. Which of the following travels fastest?

A. Sound in air
B. Sound in water
C. Sound in steel
D. Light in vacuum

Answer: D. Light in vacuum
Explanation:
Light in vacuum = fastest known speed (3×10⁸ m/s).
Sound travels fastest in solids, but still much slower than light.

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19. What causes day and night?

A. Revolution of Earth
B. Rotation of Earth
C. Tilt of Earth
D. Gravity

Answer: B. Rotation of Earth
Explanation: Earth spins on its axis → one half faces Sun (day), other half in shade (night).

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20. A simple pendulum’s time period depends on:

A. Weight of bob
B. Angle of swing
C. Length of string
D. Colour of bob

Answer: C. Length of string
Explanation: Longer string → slower swing → more time to complete one oscillation.

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21. Which property of light explains the formation of shadows?

A. Light bends
B. Light travels in straight lines
C. Light scatters
D. Light reflects

Answer: B. Light travels in straight lines
Explanation: Straight-line travel causes shadows when an object blocks light.

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22. Which quantity is a vector?

A. Speed
B. Mass
C. Distance
D. Velocity

Answer: D. Velocity
Explanation: Velocity has magnitude + direction.
Speed, mass, distance → scalars.

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23. The force that pulls objects downward is:

A. Magnetic force
B. Gravitational force
C. Muscular force
D. Electromagnetic force

Answer: B. Gravitational force
Explanation: Gravity keeps everything on Earth and makes things fall.

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24. Which form of energy is stored in food?

A. Kinetic energy
B. Chemical energy
C. Potential energy
D. Thermal energy

Answer: B. Chemical energy
Explanation: Food stores energy in chemical bonds → released during digestion.

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25. Which of these is a renewable source of energy?

A. Petrol
B. Coal
C. Natural gas
D. Solar energy

Answer: D. Solar energy
Explanation: Sunlight is inexhaustible; fossil fuels are limited and polluting.

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26. What will increase the evaporation rate of water?

A. Lower temperature
B. Less surface area
C. More wind
D. Higher humidity

Answer: C. More wind
Explanation: Wind removes water vapour → speeds up evaporation.

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27. In an electric circuit, the device that supplies energy is:

A. Switch
B. Bulb
C. Battery
D. Wire

Answer: C. Battery
Explanation: Battery provides potential difference → pushes electrons → current flows.

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28. Which motion does a ceiling fan blade show?

A. Linear motion
B. Oscillatory motion
C. Circular motion
D. Random motion

Answer: C. Circular motion
Explanation: Fan blades rotate around a fixed axis.

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29. Which gas is required for burning?

A. Nitrogen
B. Oxygen
C. Carbon dioxide
D. Hydrogen

Answer: B. Oxygen
Explanation: Oxygen supports combustion; nitrogen is inert.

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30. A rainbow always appears in which direction relative to the Sun?

A. Same direction
B. Opposite direction
C. Above the Sun
D. Below the Sun

Answer: B. Opposite direction
Explanation: Sun behind → raindrops in front → refraction + dispersion → rainbow forms.