The conversion of part of the energy into an undesirable form is called …………… .

For a given height, ………… the length l of the inclined plane, lesser will be the effort required. 

An electron emitter must have ____ work function and ____ melting point. 

Name one property of waves that do not change when the waves pass from one medium to another?

A force is applied in i) a non- rigid body and ii) a rigid body. How does the effect of the force differ in the above two cases? 

A metallic ball is hanging by a string from a fixed support. Draw a neat labelled diagram showing the forces acting on the ball and the string. 

What is the weight of the body placed at the center of the earth? 

Is it possible to have an accelerated motion with a constant speed? Explain. 

9.

i) When does a force do work?

ii) What is the work done by the moon when it revolves around the Earth? 

Calculate the change in kinetic energy of a moving body if it’s velocity is reduced to 1/3^rd of the initial velocity.