Concept simulationPhysics

Ray Optics Bench

Drag an object and a lens or mirror while principal rays redraw and the image changes live.

The idea to rememberImage position, orientation and size follow from how principal rays converge or appear to diverge. Real images form where rays physically meet; virtual images form where their backward extensions meet.

This is a conceptual visualisation built to show how the physics behaves — it deliberately shows direction and relative strength, not exact numerical values.

What this ray optics bench simulation shows

This ray optics simulation is an interactive optical bench for convex lenses, concave lenses, concave mirrors and convex mirrors. Drag the object or optical element and the principal rays redraw immediately to show where the image forms.

The construction follows the ideal paraxial model used in JEE and NEET ray diagrams. It focuses on image nature, orientation and relative size rather than displaying arbitrary distances.

How to explore the concept

Choose one of the four lens or mirror modes.
Drag the object across the focal markers and watch the ray construction and image state change.
Drag the optical element to vary the object distance without changing the object itself.
Compare solid rays that physically meet with dashed backward extensions that locate virtual images.

What to observe and learn

Watch for these changes

A convex lens can form a real inverted image or a virtual upright image, depending on whether the object is outside or inside the focus.
A concave lens forms a virtual, upright and diminished image for every supported object position.
A concave mirror changes from a real inverted image to a virtual upright image when the object crosses the focus.
A convex mirror forms a virtual, upright and diminished image behind the mirror.
At the focus of a converging optic, the outgoing rays are parallel and the image is at infinity.

Physics exam connections

Identifying real versus virtual images.
Predicting upright or inverted orientation and magnified or diminished size.
Recognising focal-point transitions for converging lenses and mirrors.
Drawing canonical principal rays for lenses and spherical mirrors.

Theory behind the simulation

Principal-ray diagrams provide a geometric way to apply the thin-lens and spherical-mirror relations. Real images form where reflected or refracted rays physically meet. Virtual images form where diverging rays appear to originate when extended backward.

The simulation uses the standard paraxial approximation: rays remain close to the principal axis and optical elements are ideal. Within that model, the image position, orientation and relative size follow the usual lens and mirror equations.

What the model simplifies

This simulation is designed for conceptual understanding. Its states follow the standard theory, while deliberately avoiding uncalibrated numerical readouts.

The model assumes ideal thin lenses and spherical mirrors in the paraxial limit.
Chromatic and spherical aberration, diffraction, thick-lens effects and off-axis distortion are not represented.
Distances are visual relationships, not measurements from a physical laboratory.

Frequently asked questions

When does a convex lens form a virtual image?

A convex lens forms a virtual, upright and magnified image when the object is placed between the lens and its principal focus.

Why are virtual-image rays shown with dashed lines?

The physical rays do not travel along those backward extensions. The dashed lines show where the diverging rays appear to originate, which locates the virtual image.

What happens when the object is at the focus?

For a converging lens or concave mirror, the outgoing rays become parallel. They do not meet at a finite distance, so the image is described as being at infinity.

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