If the absolute refractive indices of glass and water are $${3 \over 2}$$ and $${4 \over 3}$$ respectively, what will be the ratio of velocity of light in glass and water?

A positive charge +q is placed at the centre of a hollow metallic sphere of inner radius a and outer radius b. The electric field at a distance r from the centre is denoted by E. In this regard, which one of the following statements is correct?

The following items consist of two statements, Statement I and Statement II. Examine these two statements carefully and select the correct answer using the codes given below.

Statement I The pitch of sound wave depends upon its frequency.

Statement II The loudness of the sound wave depends upon its amplitude.

The following items consist of two statements, Statement I and Statement II. Examine these two statements carefully and select the correct answer using the codes given below.

Statement I Sound waves cannot propagate in vacuum.

Statement II Sound waves are elastic waves and require a medium to propagate.