Physics

Class 10

Interactive Science Lab

Reflection & Spherical Mirrors (Unit 13)

Explore the laws of reflection, plane mirror geometry, and all six concave-mirror image-formation cases with a draggable object and live ray diagrams.

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Reflection & Spherical Mirrors

Explore the laws of reflection, plane mirror geometry, concave mirror ray diagrams with all six image-formation cases, and convex mirror properties with an interactive draggable object and live ray paths.

Class 10 Physics

Unit 13: Sections 13.1 & 13.2

Concave Mirror

Position Zone:Beyond C

Interactive Optics Controls

Object Distance (p)

30.0 cm

Quick Snaps:

Focal Length (f)10 cm

Short Focus (5 cm)Standard (10 cm)Long Focus (20 cm)

6 Textbook Image Cases (Table 13.1):Click to load canonical case

Display Layers:

Interactive Optics Controls

Object Distance (p)

30.0 cm

Quick Snaps:

Focal Length (f)10 cm

Short Focus (5 cm)Standard (10 cm)Long Focus (20 cm)

6 Textbook Image Cases (Table 13.1):Click to load canonical case

Display Layers:

Live Image Formation Analysis

Case 2

NATUREReal Image(In front of mirror)

ORIENTATIONInverted (Upside-down ↓)

SIZE / SCALEDiminished0.5× Object

Object Dist (p)30.0 cm

Image Dist (q)+15.0 cm

Magnification (m)-0.50

Focal Length (f)+10 cm

Why Does This Image Form Here?

Because the object is beyond C (p > 2f), the reflected rays converge between the focus (F) and center of curvature (C). The image formed is real, inverted, and diminished (|m| < 1).

Board Exam Tip: Real images are always inverted in spherical mirrors and can be captured on a physical screen placed at distance q.

Laws of Reflection

Class 10 Physics — Unit 13, Section 13.1

First Law of Reflection

∠i = ∠r

The angle of incidence is equal to the angle of reflection. Both angles are measured from the normal to the reflecting surface.

Second Law of Reflection

Incident ray, reflected ray & normal → coplanar

The incident ray, the reflected ray, and the normal to the reflecting surface at the point of incidence all lie in the same plane.

Key Terms

Incident ray:The ray of light that strikes the reflecting surface.

Reflected ray:The ray that bounces back after reflection.

Normal:A line perpendicular to the reflecting surface at the point of incidence.

Point of reflection (P):The point where the incident ray strikes the mirror surface.

Angle of incidence (∠i):Angle between the incident ray and the normal.

Angle of reflection (∠r):Angle between the reflected ray and the normal.

Regular Reflection

Occurs on smooth, polished surfaces. Parallel incident rays remain orderly after reflection. Example: plane mirror, still water.

Irregular / Diffused Reflection

Occurs on rough surfaces. Reflected rays scatter in many directions. Example: paper, walls, rough wood. Allows objects to be seen from multiple angles.

Spherical Mirror Equations

Class 10 Physics — Unit 13, Section 13.2

Mirror Equation

1/f = 1/p + 1/q

Sub: 1/10 = 1/30.0 + 1/15.0

Result:q = 15.0 cm

Image Distance (rearranged)

q = (p × f) / (p − f)

Sub: q = (30.0 × 10.0) / (30.0 − 10.0)

Result:15.0 cm

Magnification

m = −q / p = h′ / h

Sub: m = −(15.0) / 30.0

Result:-0.50

m < 0 → inverted image · m > 0 → erect image · |m| < 1 → diminished · |m| > 1 → enlarged

Radius of Curvature

R = 2f

Sub: R = 2 × 10

Result:20 cm

The distance from P to C is twice the focal length.

Three Principal Ray Rules (Concave Mirror)

Rule 1: Parallel ray → through F

A ray parallel to the principal axis is reflected through the focus F.

Rule 2: Through F → parallel to axis

A ray passing through F is reflected parallel to the principal axis.

Rule 3: Through C → retraces path

A ray directed toward the centre of curvature C reflects back along its own path.

Sign Convention

Textbook convention — distances measured from P

Distances measured from:P (pole / optical centre)
Real distances (in front of mirror):positive (+)
Virtual distances (behind mirror):negative (−)
Concave mirror focal length:f > 0 (positive)
Convex mirror focal length:f < 0 (negative)
Object distance p:always positive (object in front)
Image distance q > 0:real image (in front of mirror)
Image distance q < 0:virtual image (behind mirror)
Magnification m < 0:inverted image
Magnification m > 0:erect image

⟳ Convex Mirror Applications

Always Virtual · Erect · Diminished

Convex mirrors produce a virtual, erect, and diminished image for all object positions. This gives them a wider field of view than a plane mirror of the same size — making them useful wherever a broad visual coverage is needed.

🚗

Rear-view / wing mirrors in vehicles

Convex mirrors are fitted as rear-view and wing mirrors in cars, buses, and trucks. They provide drivers with a wider field of view of traffic behind them.

Physics principle: A convex mirror always produces a virtual, erect, and diminished image regardless of object distance. This means a wider region of the road is visible in a smaller area.

🚗

Traffic safety / blind-turn mirrors

Large convex mirrors are placed at sharp road bends, shop corners, and car park exits to allow drivers and pedestrians to see around blind spots.

Physics principle: The wide field of view from a convex mirror (|m| < 1, m > 0) lets users see a large area that would otherwise be hidden around the corner.

⌒ Concave Mirror Applications

Converging Mirror

Concave mirrors converge reflected rays to a focal point (or produce magnified virtual images), making them useful in magnification and energy-focusing applications.

🔍

Dentist's / doctor's examination mirror

Dentists hold a small concave mirror near a tooth. The tooth appears magnified and upright, making examination easier.

Physics principle: When the object (tooth) is placed between P and F, the concave mirror produces a virtual, erect, and enlarged image (Case 6, m > 1).

🔍

Shaving / make-up mirror

Concave mirrors are used as shaving mirrors to produce an enlarged, upright image of the face.

Physics principle: By holding the face between P and F, the image is virtual, erect, and enlarged — making shaving or applying make-up easier.

🔍

Solar cooker / solar furnace

A large concave reflector focuses parallel sunlight onto a small area (the focal point F), generating intense heat for cooking.

Physics principle: When incoming sunlight is treated as being from infinity, all rays converge at F after reflection (Case 1). The concentrated energy produces high temperatures.

| Plane Mirror

Plane mirrors form the familiar upright reflection used in everyday mirrors (bathroom mirrors, dressing mirrors). They produce a virtual, erect, same-size image at the same distance behind the mirror as the object is in front.

Six Cases of Image Formation

Table 13.1 — Concave Mirror (textbook reference). Click any case to visualize it.

Class 10 · Unit 13.2

Quick Reference Table (Table 13.1)

#	Object Position	Image Position	Image Size	Nature
1	At infinity	At the focus F	Highly diminished, point-sized	Real and inverted
2	Beyond C (p > 2f)	Between F and C	Diminished	Real and inverted
3	At C (p = 2f)	At C	Same size	Real and inverted
4	Between C and F (f < p < 2f)	Beyond C	Enlarged	Real and inverted
5	At F (p = f)	At infinity	Highly enlarged	Real and inverted
6	Between P and F (0 < p < f)	Behind the mirror	Enlarged	Virtual and erect

Note on Cases 1 & 5 (Edge Cases)

Case 1 (Object at ∞): All rays from a very distant object arrive parallel to the principal axis and converge at F after reflection. Image is a point.

Case 5 (Object at F): Reflected rays become parallel — they never converge in front of or behind the mirror. The image is conceptually at infinity.

Syllabus Mapping & Learning Objectives

This interactive tool is modeled directly after the official Pakistani textbook curriculam (Sindh Textbook Board, Federal Board Islamabad, and Punjab Textbook Board). It provides live parameter tuning so students can test hypotheses, predict exam outcomes, and observe physical/chemical laws mathematically.

Key Topics Covered

ReflectionSpherical MirrorsConcave MirrorConvex MirrorRay DiagramsMirror Equation

More Study Resources

Pair this simulation with verified solved board past papers and chapter revision notes.

Solved Board Past Papers Chapter-Wise Revision Guides Online Scientific Calculator