Draw a ray diagram to illustrate the action of a convergent lens as reading glasses or a magnifying glass.

A prism deviates a monochromatic ray of light through an angle $\delta$ when the angle of incidence at the surface of the prism is $\text{'}i\text{'}$.
(i) Draw a graph showing the variation of $\mathrm{\delta }$ with $i$. On your graph, show the angle of minimum deviation?

(ii) A prism deviates a monochromatic ray of light through an angle $\delta$ when the angle of incidence at the surface of the prism is $\text{'}i\text{'}$.
What is the relation between the angle of incidence and the angle of emergence when the ray suffers minimum deviation?

Two isosceles right angled prism are arranged as shown in the figure. Copy the diagram and complete the path of the ray AB along which it passes through the prisms and comes out. Name the phenomenon being displayed by the path of the ray in the given diagram.

Define the terms: amplitude and frequency for sound waves.

Under what circumstances does one get an electric shock from an electrical gadget?