All Free Everyday Science MCQs with Answers

1931. Dioptre is used to measure ?

• A. Lens refractive power
• B. Luminous intensity
• C. Power
• D. Distance of heavenly bodies

Explanation: A dioptre is the unit of optical power of a lens, calculated as the reciprocal of its focal length in metres. It is not a unit of luminous intensity or astronomical distance.

1932. A transformer works on the principle of _______________?

• A. Self induction
• B. Mutual induction
• C. Generator
• D. Inverter

Explanation: A transformer transfers alternating-current energy between coils through a changing magnetic field, which induces voltage in the secondary coil. This process is called mutual induction because two separate coils interact.

1933. A tight-rope walker carries a long pole which he holds across his body. The purpose of this pole is to____________?

• A. Prop him up if he falls
• B. Spread out his weight and reduce the pressure on the rope
• C. Add extra weight to keep the rope tightly stretched
• D. To keep the centre of gravity always vertically above the rope

Explanation: The pole helps the walker maintain balance by lowering the combined centre of gravity and increasing rotational inertia. This makes it easier to keep the centre of gravity vertically above the rope.

1934. According to the definition of 1 KWh, a 100 watt bulb consumes one unit of electricity in____________?

• A. 1 hours
• B. 5 hours
• C. 10 hours
• D. 15 hours

Explanation: One kilowatt-hour is the energy used by a 1,000-watt appliance running for one hour. A 100-watt bulb therefore needs 10 hours to use 1 kWh, or one unit of electricity.