Physics Past Questions and Answers

A device that converts sound energy into electrical energy is

Which of the following i. \(\beta\)-particles ii. protons iii. neutrons iv. \(\alpha\)-particles. may be found in light nuclei?

Radio waves have a velocity of 3 x 10<sup style='font-size: smaller;'>8</sup>ms<sup style='font-size: smaller;'>-1</sup>. A radio station sends out a broadcast on a frequency of 800kHz. The wavelength of the broadcast is

What is the cost of running five 50W lamps and four 100W lamps for 10 hours if electrical energy costs 2 kobo per kWh?

Which of the following statements is (are) NOT true about the emission of the photoelectrons from metallic surfaces? <br/>i. all metallic surfaces emits the same number of photoelectrons in a given light <br/>ii. most metallic surfaces emit the same number of photoelectrons in visible and infra-red light <br/>iii. a metallic surface emits photoelectrons only if the frequency of the incident light is higher than its own characteristics threshold frequency