What Are Spherical Mirrors?
We are used to seeing plane mirrors (flat mirrors) in our homes. However, mirrors can also be curved. The most common type of curved mirror is the spherical mirror.
Imagine a hollow glass sphere. If you cut a piece of it, the curved surface can act as a mirror.
- If the inner surface is shiny (reflecting), it is a Concave Mirror.
- If the outer surface is shiny (reflecting), it is a Convex Mirror.
Activity: The Spoon Experiment
Take a shiny stainless steel spoon. It acts as a curved mirror.
- Inner Side (Scoop part): Acts as a Concave Mirror. Your image may look inverted (upside down) if you are far, or magnified if you are very close.
- Outer Side (Bulging part): Acts as a Convex Mirror. Your image is always upright (erect) but smaller in size.
Visualizing Spherical Mirrors
Here is how we represent these mirrors in diagrams. The shaded side represents the non-reflecting (coated) back of the mirror.
Concave Mirror
Reflecting surface curves inwards
Convex Mirror
Reflecting surface bulges outwards
Tip
Memory Trick:
- Concave: Like a “Cave” (curves inwards).
- Convex: “Vexed” or bulging out.