A concave mirror produces three times magnified real image of an object placed at 10 cm in front of it. Where is the image located?

An object is placed at a distance of 15 cm from a concave lens of focal length 30 cm. List four characteristics (nature, position, etc.) of the image formed by the lens.

Why does a beam of light when it enters glass at an angle? Why does it not bend if it inters the glass at right angles?

A convex lens is immersed in a liquid of refractive index greater than that of glass. How will the nature of lens change?

Identify the device used as a spherical mirror or lens in following cases, when the image formed is virtual and erect in each case.
Object is placed between device and its focus, image formed is enlarged and behind it.

Which lens would you prefer to use while reading small letters from a dictionary?

Draw ray diagrams showing the image formation by a convex mirror when an object is placed:
At infinity.

An object is placed at a distance of 40cm in front of a convex mirror of radius of curvature 40cm. List four characteristics of the image formed by the mirror.

What is observed when 2mL of dilute hydrochloric acid is added to 1g of sodium carbonate taken in a clean and dry test tube? Write chemical equation for the reaction involved.

Why does a ray of light passing through the centre of curvature of a concave mirror gets reflected along same path after reflection?