Which one among the following situations is best represented by the velocity – time plot shown above?

White light while passing through a glass prism breaks up into light of different colours because

Bats can know about their prey at a distance even in the night by emitting

The ceilings of a concert hall are generally curved

An electric heater is rated 1500 watt. If electric power costs Rs 2 per kilo-watt-hour, then the cost of power for 10 hours running of the heater is

Suppose we have an iron nail and an iron ball of same mass. When submerged in water, the iron ball may float but the nail always sinks. This is because