Answer:
Power rating of heater=1.5kw
Current taken from the supply=6A
Explanation:
Power(P)=Energy/Time
Where, electrical energy=3.6*10^6J and Time=40mins=40*60s
P=3.6*10^6J/40*60s
P=1500J/s or 1500watts
P=1.5kw
Current supply:
P=VI
Where, power(P)=1500watts,Voltage supply (V)=250volts, and current(I)=?
Making current (I) the subject of the formula :
I=P/V
I=1500watts/250volts=6A
Therefore, current taken from the supply is 6A.