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Questions
Name the energy transfers which occur when an electric ball rings.
Name the energy conversion that takes place when an electric bell rings.
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Solution
An electric bell converts electrical energy to sound energy.
RELATED QUESTIONS
A ball is placed on a compressed spring. What form of energy does the spring possess? On releasing the spring, the ball flies away. Give a reason.
A ball of mass 0.20 kg is thrown vertically upwards with an initial velocity of 20 m s-1. Calculate the maximum potential energy it gains as it goes up.
A stone of mass 500 g is thrown vertically upwards with a velocity of 15 m/s. Calculate:
- the potential energy at the greatest height,
- the kinetic energy on reaching the ground, and
- the total energy at its half-way point.
Is energy a vector quantity?
What kind of energy is possessed by the following?
A stone kept on roof-top _______________
What kind of energy is possessed by the following?
Water stored in the reservoir of a dam __________.
What type of energy is possessed : by the piece of stone which is thrown away on releasing the stretched rubber strings of catapult?
A stone is thrown upwards as shown in the diagram. When it reaches P, which of the following has the greatest value of the stone?
Name the device or machine which convert :
Light energy into electrical energy.
Name the device or machine which convert :
Heat energy into kinetic energy (or mechanical energy).
Name the device or machine which convert :
Chemical energy into heat energy.
What kind of energy transformation take place at a hydroelectric power station?
Explain the transformation of energy in the following cases :
(i) A ball thrown upwards.
(ii) A stone dropped from the roof of a building.
When an object falls freely towards the earth, then its total energy :
Which of the following energy change involves frictional force?
An object is falling freely from a height x. After it has fallen a height `pi/2` , it will possess :
The device which converts mechanical energy into energy which runs our microwave oven is :
A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. The work done against the gravitational force will be (g = 10 m s–2)
An automobile engine propels a 1000 kg car (A) along a levelled road at a speed of 36 km h–1. Find the power if the opposing frictional force is 100 N. Now, suppose after travelling a distance of 200 m, this car collides with another stationary car (B) of the same mass and comes to rest. Let its engine also stop at the same time. Now the car (B) starts moving on the same level road without getting its engine started. Find the speed of the car (B) just after the collision.
A body of mass 10 kg falls from a height of 20 m to 8 m. Calculate:
- the loss in potential energy of the body, and
- the total energy possessed by the body at any instant? (Take g = 10 m s-2)
