Physics Past Questions and Answers

The capacitance of parallel plates capacitors varies

Which of the following devices does not makes use of eddy current for its action? A/An

A coil of inductance 0.12 H and resistance 4\(\Omega\), is connected across a 240V, 50Hz supply. Calculate the current through it. [\(\pi\) = 3.142]

The work function of a metal is 2.56 x 10<sup style='font-size: smaller;'>-19</sup>J. Calculate the frequency of a photon whose energy is required to eject from the metal an electron with kinetic energy of 3.0ev. [1 eV = 1.6 x 10<sup style='font-size: smaller;'>-19</sup>J, h = 6.6 x 10<sup style='font-size: smaller;'>-34</sup>Js]

The minimum energy required to cause photoelectric emission when the surface of a metal is irradiated with electromagnetic radiation of suitable frequency is called