Mirror Equation Calculator
mirror/lens equation calculator. Get instant, accurate results. Enter values for instant results with step-by-step formulas.
Reviewed for accuracy by Manoj Kumar, Mathematics Educator
Mirror Equation Calculator
Calculator
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Formula: 1/f = 1/dₒ + 1/dᵢ | m = -dᵢ/dₒ
Worked example — dᵢ=15cm, m=-0.5×
Formula
1/f = 1/dₒ + 1/dᵢ | m = -dᵢ/dₒ
Relates focal length, object distance, and image distance for mirrors and thin lenses.
Worked Examples
Example 1: Converging lens
Problem:f=10cm, dₒ=30cm
Solution:1/dᵢ=1/10-1/30=2/30, dᵢ=15cm, m=-0.5
Result:dᵢ=15cm, m=-0.5×
Frequently Asked Questions
What is the mirror/lens equation?
The mirror and thin-lens equation is 1/f = 1/dₒ + 1/dᵢ, where f is the focal length, dₒ is the object distance, and dᵢ is the image distance. Magnification is m = −dᵢ/dₒ. All distances are typically in the same unit (cm or m).
What units and sign conventions are used?
Distances are in centimetres (cm) or metres (m). For mirrors: positive dᵢ means real image (in front of mirror); negative means virtual (behind). For lenses: positive dᵢ means real image (opposite side from object). Positive magnification means upright image.
What is a real vs. virtual image in optics?
A real image forms where reflected or refracted rays actually converge and can be projected on a screen (dᵢ > 0 for mirrors). A virtual image forms where rays appear to diverge from and cannot be projected (dᵢ < 0). Plane mirrors always produce virtual images.
What are the key kinematics equations?
The four main kinematics equations relate displacement (d), initial velocity (v0), final velocity (v), acceleration (a), and time (t): v = v0 + at, d = v0t + 0.5at^2, v^2 = v0^2 + 2ad, and d = 0.5(v + v0)t. These apply only to constant acceleration.
How do lenses and mirrors work in optics?
Lenses refract light and mirrors reflect it. The thin lens/mirror equation is 1/f = 1/do + 1/di, where f is focal length, do is object distance, and di is image distance. Magnification = -di/do. Converging lenses and concave mirrors focus light; diverging lenses and convex mirrors spread it.
Reviewed for accuracy by Manoj Kumar, Mathematics Educator · Editorial policy
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