At what distance should an object be placed to obtain its real,inverted and of same size image as the object by a convex lens?

With the help of a ray diagram,show that the angle of incidence is equal to the angle of reflection when a ray is incident on a concave mirror.

Where does an object and its image coincide in a concave mirror?

Define power of a lens. What is its unit? One student uses a lens of focal length $50\, cm$ and another of $-50\, cm$. What is the nature of the lens and its power used by each of them?

Draw ray diagrams showing the image formation by a concave mirror when an object is placed:
$(a)$ Between pole $(P)$ and focus $(F)$ of the mirror.
$(b)$ Between focus $(F)$ and centre of curvature $(C)$ of the mirror.
$(c)$ At centre of curvature $(C)$ of the mirror.
$(d)$ $A$ little beyond centre of curvature $(C)$ of the mirror.
$(e)$ At infinity.

$(a)$ Water has a refractive index of $1.33$ and alcohol has a refractive index of $1.36$. Which of the two media is optically denser? Give a reason for your answer. Draw a ray diagram to show the path of a ray of light passing obliquely from water to alcohol.
$(b)$ The absolute refractive index of diamond is $2.42$ and the absolute refractive index of glass is $1.50$. Find the refractive index of diamond with respect to glass.