Image Formation in Spherical Mirrors

Concave Mirror

A spherical mirror whose reflecting surface is CURVED INWARDS towards the source of light.

Convex mirror

A spherical mirror whose reflecting surface is CURVED OUTWARDS.

PRINCIPAL AXIS

Line passing through the CENTER OF THE SPHERE and attaching to the mirror in the exact center.

RADIUS OF CURVATURE, R

The distance from the vertex to the center of curvature.

CENTER OF CURVATURE, C

The point in the center of the sphere from WHICH THE MIRROR WAS SLICED.

VERTEX, A

The point on the mirror's surface where the PRINCIPAL AXIS MEETS THE MIRROR.

FOCAL LENGTH, f

The distance from the MIRROR TO THE FOCAL POINT.

FOCAL POINT, F

The point MIDWAY between the vertex and the center of curvature.

f = ?

R / 2

R =

2f

L: same side of the mirror
O: Inverted
S: Reduced / Diminished
T: Real

CASE 1. Beyond C
L?
O?
S?
T?

L: Same side of the mirror
O: inverted
S: same size
T: real

CASE 2. At C
L?
O?
S?
T?

L: same side of the mirror
O: Inverted
S: Magnified / Enlarged
T: Real

CASE 3. Between C and F
L?
O?
S?
T?

As the object MOVES CLOSER to the mirror, the image SIZE BECOMES LARGER.

What happens to the image as the object moves closer to the mirror?

Light rays DO NOT MEET AT A POINT, that’s why there is no image formed.

CASE 4. At F
Why is there no image formed?

L: Behind the mirror
O: Upright
S: Enlarged / maginified
T: Virtual

CASE 5. In front of F
L?
O?
S?
T?

DENTAL MIRRORS
MAKE-UP MIRRORS
SHAVING MIRRORS
SOLAR COOKER

Where are concave mirrors commonly used?

L: Behind the mirror
O: Upright
S: Reduced / Diminished
T: Virtual

CONVEX MIRROR
In Any Case:
L:
O:
S:
T:

Parallel

Any incident ray traveling ________ to the PRINCIPAL AXIS on the way to the mirror will pass through the focal point upon reflection

Parallel

Any INCIDENT RAY PASSING THROUGH THE FOCAL POINT on the way to the mirror will travel _________ to the principal axis upon reflection

REAR-VIEW MIRROR
SIDE-VIEW MIRROR
SHOP MIRROR

Where are convex mirrors commonly used?