In torches,searchlights,and headlights of vehicles,the bulb is placed:

When a plane mirror is rotated by an angle $\theta$,the reflected ray turns by an angle $2\theta$. Is this statement true or false?

$(a)$ The refractive index of diamond is $2.42$. What is the meaning of this statement?
$(b)$ Redraw the diagram given below in your answer book and complete the path of the ray.
$(c)$ What is the difference between virtual images produced by concave and convex mirrors?
$(d)$ What does the negative sign in the value of magnification produced by a mirror indicate about an image?

The mirror formula is the same,irrespective of whether the mirror is a convex mirror or a concave mirror.

What is meant by power of a lens? Define its $SI$ unit. You have two lenses $A$ and $B$ of focal lengths $+10\, cm$ and $-10\, cm$ respectively. State the nature and power of each lens. Which of the two lenses will form a virtual and magnified image of an object placed $8\, cm$ from the lens? Draw a ray diagram to justify your answer.

How will you decide whether a given piece of glass is a convex lens,concave lens,or a plane glass plate?