Bohr and Biot purchased two electric kettles A and B of the same size and thickness and same volume of 0.4 litre. They studied the specififcation of kettles as under. Kettle A : specific heat capacity; 1680 J/kg-k, mass = 200 gm cost = Rs.400 Kettle B : specific heat capacity = 2450 J/kg-K mass = 400 gm cost = Rs.400. When kettle A is switched on with constant potential source, the tea begins to boil in 6 minutes. When kettle B is switched on with same source separately, tea begins to boil in 8 minutes. They made discussion on specififcation and efficiency of kettles and prepared a list of questions to draw a conclusion. Some of these are as under (take specific heat of tea liquid = 4200 J/kg-k, and density = 1000 kg/m30)
If both the kettles are joined with the same source in series one after the other. The boiling starts in kettle A & B after
(1) Four times of their original time
(2) Two times of their original time
(3) Equal to their original time
(4) Can not be ascertained from this data
