Why are some patients of diabetes treated by giving injections of insulin?

Why are some transport proteins called pumps?

Why is some space left in between two rails?

Why do some metals occurs in the native state?

Give some examples of application of heating effect of electric current in our daily life.

Give reason why is zinc better than Tin in protecting iron from corrosion?

Explain why friction is necessary to make the disc in Fig. 7.41 roll in the direction indicated. (a) Give the direction of frictional force at B, and the sense of frictional torque, before perfect rolling begins. (b) What is the force of friction after perfect rolling begins?

Give some examples of total internal reflection in nature.