Plan a practical to investigate the ratio heating of various metals using a joule meter to determine the energy input. If no joule meter is available, use an ammeter ,I, a voltmeter ,V, and heat the material for a fixed amount of time ,t, Calculate the energy transferred. Thanks :)

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.