Advertisements
Advertisements
प्रश्न
A lamp consumes 1000 J of electrical energy in 10 s. What is its power?
उत्तर
Power = `"Energy consumed (or work done)"/"Time taken"`
W = 1000 J, t = 10 s
i.e., P = `W/t`
= `(1000 J)/(10 s)`
= 100 J/s
i.e., P = 100 W
APPEARS IN
संबंधित प्रश्न
Define 1 watt of power.
An electric heater is rated 1500 W. How much energy does it use in 10 hours?
How much is the mass of a man if he has to do 2500 joules of work in climbing a tree 5 m tall? (g = 10 m s−2)
An electric heater uses 600 kJ of electrical energy in 5 minutes. Calculate its power rating.
A car of weight 20000 N climbs up a hill at a steady speed of 8 m/s, gaining a height of 120 m is 100 s. Calculate : work done by the car.
A boy weighing 40 kg carries a box weighing 20 kg to the top of a building 15 m high in 25 seconds. Calculate the power. (g = 10 m/s2)
In an experiment to measure his power, a student records the time taken by him in running up a flight of steps on a staircase. Use the following data to calculate the power of the student :
Number of steps = 28
Height of each step = 20 cm
Time taken = 5.4 s
Mass of student = 55 kg
Acceleration = 9.8 m s−2
due to gravity
In loading a truck, a man lifts boxes of 100 N each through a height of 1.5 m.
How much work does he do in lifting one box?
In loading a truck, a man lifts boxes of 100 N each through a height of 1.5 m.
How much energy is transferred when one box is lifted?
An electric motor raises a load of 0.2 kg, at a constant speed, through a vertical distance of 3.0 m in 2 s. If the acceleration of free fall is 10 m/s2, the power in W developed by the motor in raising the load is :