Free Physics in Daily Life MCQs with Answers

311. The strongest part(s) of a magnet is/are _________?

• A. North pole
• B. South pole
• C. North and south pole
• D. Median of north and south pole

Explanation: A bar magnet is strongest at both of its poles, where the magnetic field lines are most concentrated. Neither pole alone is stronger than the other under ordinary conditions.

312. Who discovered the Gamma Rays?

• A. Alfred Marshall
• B. Paul Villard
• C. Bohar
• D. Jabar bin Hayan

Explanation: French physicist Paul Villard discovered gamma rays in 1900 while studying radiation from radium. Rutherford later named this penetrating radiation gamma rays.

313. The gravitational pull at the lunar surface is ________ of Earth?

• A. 1/3
• B. 1/4
• C. 1/5
• D. 1/6

Explanation: The Moon's surface gravity is about 1.62 m/s², compared with Earth's 9.81 m/s², making it approximately one-sixth of Earth's. This is why objects weigh much less on the Moon.

314. X-rays were discovered by __________?

• A. Wilhelm Conrad Roentgen
• B. Thomson
• C. Ernest Rutherford
• D. Bacquerel

Explanation: Wilhelm Conrad Röntgen discovered X-rays in 1895 while experimenting with cathode-ray tubes. Thomson, Rutherford, and Becquerel made other major discoveries in atomic and radiation science.

315. Central Color of Rainbow is__________?

• A. Blue
• B. Green
• C. Red
• D. Indigo

Explanation: A rainbow's colors run from red on the outer edge to violet on the inner edge, with green near the middle. This arrangement results from dispersion of sunlight in raindrops.

316. Candela is the basic unit of_________________?

• A. luminous intensity
• B. heat producing value
• C. Thermodynamic temperature
• D. radioactive decay

Explanation: Candela is the SI base unit of luminous intensity, the amount of light emitted in a particular direction. Temperature, heat value, and radioactive decay have different units.

317. Steradian is the unit of_______________?

• A. Solid angle
• B. Liquid angle
• C. Gas angle
• D. Plain angle

Explanation: A steradian measures a solid angle in three-dimensional space, just as a radian measures a plane angle in two dimensions. Liquid and gas are not types of angle units.

318. Siemens is the unit of__________________?

• A. Electrical Conductance
• B. Magnetic Conductance
• C. Electrical Capacitance
• D. Magnetic Capacitance

Explanation: The siemens is the SI unit of electrical conductance, which is the reciprocal of resistance: S = 1/Ω. Capacitance is measured in farads, not siemens.

319. The temperature at which water boils depends mainly on ____________?

• A. Air temperature
• B. Relative humidity
• C. Air pressure
• D. Air density
• E. The specific heat of air

Explanation: Boiling occurs when a liquid's vapour pressure equals the surrounding pressure, so water boils at a lower temperature on high mountains and a higher temperature in a pressure cooker. Air temperature and humidity do not primarily set the boiling point.

320. The total energy of revolving electron in an atom_____________

• A. Will always be positive
• B. Can never be positive
• C. Can have any value above zero
• D. Cannot be negative

Explanation: An electron bound to an atom has negative total energy when zero energy is defined as the electron completely free from the atom. A positive total energy would describe an unbound electron, so “can never be positive” is the intended choice.