1. Explain with a diagram how periscope is useful to the navigators in a submarine.
2. Explain why the image in a mirror is called a ‘Virtual Image’.

If steel is more dense that lake water, why can a boat float

Red light strikes a metal surface and electrons are ejected. if violet light is now used with a 10% greater intensity, what will happen to the ejection rate (number of ejected electrons per second) and the maximum energy of the electrons? a) greater ejection rate; same maximum energyb) same ejection rate; greater maximum energyc) greater ejection rate; greater maximum energyd) same ejection rate; same maximum energye) none of the above answers are correct

Hydrogen and helium are both members of?