Narendra Kumar Solutions for Chapter: Light - Reflection and Refraction, Exercise 6: HIGHER ORDER THINKING SKILLS (HOTS)

An object $1 \mathrm{cm}$ high produces a real image $1.5 \mathrm{cm}$ high, when placed at a distance of $15 \mathrm{cm}$ from concave mirror. Calculate the position of the image.

The following table gives the values of refractive indices of a few media:

Use this table to give an example of (i) a medium pair so that light speeds up when it goes from one of these media to another (ii) a medium pair so that light slows down when it goes from one of these media to another.

Refractive index of water is $\frac{4}{3}$ and that of the glass is $\frac{3}{2}$ with regard to air. What is the refractive index of glass with respect to the water?

How much time will light take to cross $4 \mathrm{mm}$ thick glass pane if refractive index of glass is $\raisebox{1ex}{$3$}\!\left/ \!\raisebox{-1ex}{$2$}\right.$?

Explain with the help of a diagram, why a pencil partly immersed in water appears to be bent at the water surface?

A diverging lens of focal length $20 \mathrm{cm}$ forms an image of $12 \mathrm{cm}$ from the lens. Draw a scale diagram for the formation of image.

A concave lens of focal length $25 \mathrm{cm}$ and a convex lens of focal length $20 \mathrm{cm}$ are placed in contact with each other. What is the power of this combination? Also, calculate focal length of this combination.

The image of an object formed by a lens is of magnification $-1$. If the distance between the object and its image is $60 \mathrm{cm}$, what is the focal length of the lens? If the object is moved $20 \mathrm{cm}$ towards the lens, where would the image be formed? State reason and also draw a ray diagram in support of your answer.