In geometric optics, the power of a lens is defined as the reciprocal of its: MCQ with Answer and Explanation

Explanation:
Heat flows until temperatures equal, i.e., thermal equilibrium. Not necessarily 50°C unless heat capacities equal.

Explanation:
While James Clerk Maxwell predicted electromagnetic waves mathematically, it was the German physicist Heinrich Hertz who successfully built the first spark-gap transmitter in 1887. He physically generated and detected radio waves in his laboratory, proving Maxwell's theories right. The SI unit of frequency, the Hertz (Hz), is named in his absolute honor.

Explanation:
Resolving power is a telescope's ability to distinguish closely spaced objects (like double stars) as separate. It is proportional to D / lambda, where D is the diameter (aperture) of the objective lens and lambda is the wavelength of light. Increasing the aperture D directly and strictly increases the resolving power.