question_answer

Heater coil A takes t1 second to boil certain quantity of water. Heater coil B takes \[{{t}_{2}}\]second to boil same quantity of water. If A and B are connected in series, the time taken to boil the same quantity of water by the combination is

A)  \[\sqrt{{{t}_{1}}{{t}_{2}}}\]                                        

B)  \[{{t}_{1}}+{{t}_{2}}\]

C)  \[\frac{1}{2}({{t}_{1}}+{{t}_{2}})\]                          

D) \[\frac{{{t}_{1}}{{t}_{2}}}{{{t}_{1}}+{{t}_{2}}}\]