A tightly closed metal lid of a glss bottle can be opened more easily if it is put in hot water for some time. Expoain.

Assertion: Current is passed through a metallic wire, heating it red. When cold water is poured on half of its portion, then rest of the half portion become more hot. Reason: Resistance decreases due to decrease in tem perature and so current through wire increases.

A heating coil can heat the water of a vessel from 20^(@)C to 60^(@)C in 30 minutes . Two such heating coils are put in series and then used to heat the same amount of water through the same temperature range. The time taken now will be (neglecting thermal capacity of the coils)