Physics - Study Mode
[#171] If ice floating on water in a vessel melts, the water level in the vessel ________ .
Correct Answer
(B) Does not change
Explanation
Solution: If ice floating on water in a vessel melts, the water level in the vessel does not change.
[#172] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because
Correct Answer
(C) Cohesion of mercury is greater than its adhesion with glass
Explanation
Solution: On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because cohesion of mercury is greater than its adhesion with glass.
[#173] The velocity of falling rain drops attains a terminal value because of
Correct Answer
(D) Viscous force exerted by air
Explanation
Solution: The velocity of falling rain drops attains a terminal value because of viscous force exerted by air.
[#174] Which one is the unit of surface tension of a liquid
Correct Answer
(B) Electron volt /cm 2
Explanation
Solution: The unit of surface tension of a liquid is Electron volt /cm 2 .
[#175] Red light has a wavelength of 70 A°. In "nm" it is
Correct Answer
(A) 7 nm
Explanation
Solution: Angstroms (A°) to nanometers (nm) is: 1 A° = 0.1 nm So, to convert 70 A° to nanometers: 70 A° × 0.1 nm/A° = 7 nm Therefore, the correct answer is Option A: 7 nm .