An electric kettle consists of two filaments F1 and F2 of different resistances 𝑅1 and 𝑅2 respectively,
connected in parallel with separate switches. With a certain fixed amount of water in the kettle pot to
prepare the tea, when only F1 is switched on, it takes 4 minute to boil the water. When F1 and F2 both are
switched on simultaneously, it takes 3 minute to boil the same amount of water up to the same
temperature. The time taken to boil the same amount of water when only F2 is switched on (assume that
entire heat radiated by filaments is used in boiling the water starting from the same room temperature in
each case) is