All Free Everyday Science MCQs with Answers

1581. Why the needle of iron swims on water surface when it is kept gently ?

• A. It will remain under the water, when it will displace more water than its weight
• B. the density of needle is less than that of water
• C. due to surface tension
• D. due to its shape

Explanation: A gently placed iron needle can be supported by the water surface because surface tension acts like a stretched film around it. This does not mean iron is less dense than water; the needle would otherwise sink.

1582. Which of the following are not deflected by electric and magnetic fields ?

• A. Alpha rays
• B. Beta rays
• C. Gamma rays
• D. None of these

Explanation: Gamma rays carry no electric charge and are not deflected by electric or magnetic fields. Alpha and beta rays are charged particles, so their paths bend in such fields.

1583. What is the magnetic field at any point in the open space inside the toroid?

• A. zero
• B. one
• C. Depends on the current in the turns
• D. Depends on number of turns

Explanation: For an ideal toroid, the magnetic field outside the windings and in the central open space is zero because the magnetic field lines remain confined within the toroidal core. The field inside the windings depends on current and turns.

1584. 1 Meter = _________ millimeters?

• A. 10000 millimeters (mm)
• B. 10 millimeters (mm)
• C. 100 millimeters (mm)
• D. 1000 millimeters (mm)

Explanation: The metric prefix milli means one-thousandth, so one metre contains 1,000 millimetres. Thus, 1 m = 1000 mm.

1585. 1 Meter = _________?

• A. 1000 centimeters (cm)
• B. 100 centimeters (cm)
• C. 10 centimeters (cm)
• D. 10000 centimeters (cm)

Explanation: The prefix centi means one-hundredth, so one metre is divided into 100 centimetres. Thus, 1 m = 100 cm.

1586. Which one of the following waves are used by the common TV remote control?

• A. Radio waves
• B. Lasers
• C. Infrared waves
• D. Ultrasonic waves

Explanation: TV remotes usually send coded signals through infrared radiation, which is invisible to the eye and detected by a sensor on the television. Radio and ultrasonic waves are used in other wireless or control applications.

1587. Wireless transmission can be done via _____________?

• A. A Infrared waves
• B. Radio waves
• C. Microwaves
• D. All of these

Explanation: Wireless communication can use radio waves, microwaves, or infrared waves, depending on the device and distance. All three transfer information without a physical connecting wire.

1588. What is unit of conductivity?

• A. Ohm
• B. Watt
• C. mho
• D. None of these

Explanation: Electrical conductivity is measured in siemens, formerly called mho, which is the reciprocal of resistance measured in ohms. Watt measures power, not conductivity.

1589. Parses is a unit used to measure: __________?

• A. Distance
• B. Time
• C. Speed
• D. Force

Explanation: A parsec, apparently misspelled here as “parses,” is a unit of astronomical distance, equal to about 3.26 light-years. It is not a unit of speed or time.

1590. Curie is a unit of measuring the intensity of ___________?

• A. Radioactivity
• B. Quantity of Heat
• C. Work or Energy
• D. Power

Explanation: The curie is an older unit of radioactivity, measuring the rate of radioactive decay. In the SI system, the corresponding unit is the becquerel.