When a solid object is immersed in water, there is a loss in its weight. This loss is

An electric lamp of 100 watt is used for 10 hours per day. The ‘units’of energy consumed in one day by the lamp is

A stable nucleus (light with A < 10) has

Kilowatt-hour is the unit of

Which one among the following is used to make periscope?

Potential at a point due to a point charge is V. The charge is doubled and also the distance of the point from the charge is doubled. The new potential is