Advertisements
Advertisements
प्रश्न
If a 1200 W electric iron is used daily for 30 minutes, how much total electricity is consumed in the month of April?
Advertisements
उत्तर
Data: P = 1200 W, t = 30 days × `"30 minutes"/"day" xx (60 "s")/("minute") = 54000 "s"` W = ?
P = `"W"/"t"`
∴ W = Pt
∴ W = 1200 W × 54000 s
= 648 × 105 J
= 6.48 × 107 J
= `(6.48 xx 10^7 "J")/(3.6 xx 10^6)` units
= 18 units
APPEARS IN
संबंधित प्रश्न
A pump on the ground floor of a building can pump up water to fill a tank of volume 30 m3 in 15 min. If the tank is 40 m above the ground, and the efficiency of the pump is 30%, how much electric power is consumed by the pump?
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.
Rajan exerts a force of 150 N in pulling a cart at a constant speed of 10 m/s-1. Calculate the power exerted.
1 H.P. = .........
Match the following
| column A | Column B |
| A stone at a height | power |
| A Moving ball | joule |
| Energy | work done in 1 s |
| Power | potential energy |
| Watt | kinetic energy |
Two coolies A and B do some work in time 1 minute and 2 minute respectively. The power spent is
The expression of power P is
1 H.P. is equal to
Name the physical quantity which is measured in calorie. How is it related to the S.I. unit of the quality?
Differentiate between watt and watt hour.
What is the minimum velocity with which a body of mass m must enter a vertical loop of radius R so that it can complete the loop?.
A wind-powered generator converts wind energy into electric energy. Assume that the generator converts a fixed fraction of the wind energy intercepted by its blades into electrical energy. For wind speed v, the electrical power output will be proportional to ______
Arrive at an expression for power and velocity. Give some examples for the same.
A ball with a velocity of 5 ms−1 impinges at an angle of 60˚ with the vertical on a smooth horizontal plane. If the coefficient of restitution is 0.5, find the velocity and direction after the impact.
Calculate the power of a crane in watts, which lifts a mass of 100 kg to a height of 10 m in 20s.
A man is throwing bricks of mass 2 kg onto a floor from a height of 2 m. Bricks reach the floor at a speed `2sqrt(10)` m/s. Man throws 10 bricks in a minute. If the power of man is W watt then `3/10` W is equal to ______ W.
Sand is being dropped from a stationary dropper at a rate of 0.5 kgs-1 on a conveyor belt moving with a velocity of 5 ms-1. The power needed to keep belt moving with the same velocity will be ______.
Calculate the power spent by a crane while lifting a load of mass 2000 kg, at velocity of 1.5 ms-1. (g = 10 ms-2)
Name the quantity which is measured in kW.
