Experiment Mode

Incident Angle (i) 45.0°

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Angle of Reflection (r) 45.0°

Deviation (δ) 90.0°

PLANE MIRROR

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Ray Optics

Reflection of Light

Understanding the fundamental laws governing mirrors and optical instruments.

Laws of Reflection

[Image of laws of reflection diagram]

The angle of incidence ($\angle i$) is always equal to the angle of reflection ($\angle r$).
The incident ray, the reflected ray, and the normal to the surface at the point of incidence all lie in the same plane.

$$ \angle i = \angle r $$

Angle of Deviation

The angle of deviation ($\delta$) is the angle between the path of the incident ray and the reflected ray.

Since the total angle on a straight line is $180^\circ$, and $\angle i = \angle r$:

$$ \delta = 180^\circ - (i + r) = 180^\circ - 2i $$

Principle of Periscope

A periscope uses two plane mirrors inclined at an angle of $45^\circ$.

Light from the object hits the first mirror and is deviated by $90^\circ$ downwards.
It hits the second mirror and is deviated again by $90^\circ$ horizontally towards the eye.
The final image is erect and virtual.

Q: What is a virtual image?

An image formed by the apparent intersection of light rays (extrapolated backwards). It cannot be caught on a screen.

Q: Why is an ambulance written backwards?

Due to lateral inversion. In the rear-view mirror of the car ahead, it will appear correctly.

Trial #	Angle of Incidence (i)	Angle of Reflection (r)	Deviation (δ)
No readings recorded.

Mean Deviation

Average of all recorded trials

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