Advertisements
Advertisements
प्रश्न
An electric heater of power 3 kW is used for 10 h. How much energy does it consume? Express your answer in
- kWh,
- joule.
Advertisements
उत्तर
Given:
Power of Heat P = 3 kW
Time t = 10 h.
(i) Energy consumed = power × time
Energy = 3 kW × 10 h = 30 kWh
(ii) 1 kilowatt hour (kWh) = 3.6 × 106 J
30 kWh = 30 × 3.6 × 106 J
= 108 × 106 J
= `108/100 xx 100 xx 10^6` J
= 1.08 × 108 J
APPEARS IN
संबंधित प्रश्न
A family uses 8 kW of power.
- Direct solar energy is incident on the horizontal surface at an average rate of 200 W per square meter. If 20% of this energy can be converted to useful electrical energy, how large an area is needed to supply 8 kW?
- Compare this area to that of the roof of a typical house.
Power P= ............ /time taken.
1 H.P. = .........
Two coolies A and B do some work in time 1 minute and 2 minute respectively. The power spent is
1 H.P. is equal to
Arrive at an expression for power and velocity. Give some examples for the same.
Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine. The losses due to frictional force are 10% of the input energy. How much power is generated by the turbine? (g = 10 m/s2)
Calculate the power of a crane in watts, which lifts a mass of 100 kg to a height of 10 m in 20s.
Name the quantity which is measured in kWh.
Name the quantity which is measured in kW.
