Solve these problems

A hair dryer contains three heating elements. The figure below shows the circuit diagram for the heating elements in the hair dryer. In the figure the heating elements are represented by resistor symbols. Power [| supply \" S2 $3 FE (a) Complete the sentence. The three resistors in above diagram are connected in with the power supply. (1) (b) Which switch must always be closed for the hair dryer to work? Tick (v) one box. 84 S2 33 (1) (c) Which switches must be closed for the hair dryer to work at maximum power output? Tick (v) one box. $1 and Ss $1 and $3 S14, So and 83 (1) (d) The heating elements have a maximum power output of 1200 W. The energy transferred to the heating elements to reach normal operating temperature is 3600 J. Calculate the time taken for the heating elements to reach normal operating temperature at maximum power output. Time = s (3)