What Are Spherical Mirrors? In simple terms, a spherical mirror is a curved reflector cut from a hollow sphere—silvered on the inner side it becomes a concave mirror that brings parallel light rays together at a real focal point, and silvered on the outer side it becomes a convex mirror that spreads rays as if from a virtual focus.
Mastering how these mirrors bend light, form images, and follow the mirror equation is crucial for Class 10 boards, NEET and JEE aspirants. To see clear ray-diagram demos and solved examples, watch our full YouTube tutorial also!
What Are Spherical Mirror?
Spherical mirrors are reflective surfaces shaped from a segment of a hollow sphere: concave mirrors (inner surface silvered) converge parallel light rays to a real focal point, while convex mirrors (outer surface silvered) diverge rays as if they originate from a virtual focus behind the mirror
Types of Spherical Mirrors
Concave Mirror (Converging):
- Inner surface is reflective
- Parallel rays meet at the real focus (F) in front of the mirror
- Can form both real, inverted images and virtual, magnified images
Convex Mirror (Diverging):
- Outer surface is reflective
- Rays appear to come from a virtual focus (F′) behind the mirror
- Always forms upright, reduced, virtual images
Key Terms You Must Know
- Pole (P): Midpoint of the mirror’s surface
- Center of Curvature (C): Centre of the original sphere; distance PC = R
- Principal Axis: Line through P and C
- Focal Point (F): Where parallel rays converge (concave) or appear to diverge from (convex); f = R/2
- Object Distance (u): Distance from object to P
- Image Distance (v): Distance from image to P
- Magnification (m): Ratio of image height to object height = –v/u
Mirror Formula & Sign Conventions
Sign rules (Cartesian convention):
- u is always negative (object in front of mirror)
- f is positive for concave, negative for convex
- v is positive for real images, negative for virtual images
How Images Form
Concave mirrors can produce different images depending on object position:
- Beyond C: Real, inverted, smaller image between C and F
- At C: Real, inverted, same-size image at C
- Between C and F: Real, inverted, magnified image beyond C
- Between F and P: Virtual, upright, magnified image behind mirror
Convex mirrors always yield a virtual, upright, reduced image behind the mirror, giving you a wide field of view.
Real-World Uses
- Concave Mirrors: Makeup/shaving mirrors, solar concentrators, reflecting telescopes, car head-lamps
- Convex Mirrors: Vehicle side-view mirrors, security and hallway mirrors, ATM surveillance
Watch Our Video Tutorial
Seeing is believing! For clear ray-diagram demonstrations, solved examples, and exam tips, check out our YouTube video “What Are Spherical Mirrors?” on the Convex Classes Jaipur channel.
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Frequently Asked Questions
Q1. Why is focal length half the radius of curvature?
Because the focus lies halfway between the mirror’s pole and its center of curvature (f = R/2).
Q2. When does a concave mirror form a virtual image?
When the object is placed between the pole (P) and focal point (F), you get a virtual, upright, enlarged image.
Q3. How do I apply the mirror formula in problems?
Plug your values into 1/f=1/v+1/u1/f = 1/v + 1/u, keeping track of signs for u, v, and f.
Q4. Why do convex mirrors reduce blind spots?
They diverge light rays, making images smaller and covering a larger area behind you.
Q5. Where can I practice more?
Join our online test series or watch the full video on our YouTube channel for step-by-step solutions.
