Light and Lenses

What is the Law of Reflection?

The law states that the angle of incidence (i) is equal to the angle of reflection (r). Both are measured from the normal to the surface.

Define Refractive Index (n) using the speed of light.

n = \frac{c}{v}, where c = 3 \times 10^8 \text{ m/s} is the speed of light in a vacuum and v is the speed in the material.

What is Snell's Law for refraction?

n = \frac{\sin(i)}{\sin(r)}, where i is the angle in the less dense medium (usually air) and r is the angle in the more dense medium.

Define Total Internal Reflection (TIR).

TIR occurs when light travels from a denser to a less dense medium and the angle of incidence (i) is greater than the critical angle (c).

What is the formula for the Critical Angle (c)?

\sin(c) = \frac{1}{n}

What is Dispersion in a prism?

The splitting of white light into a spectrum of colors because different wavelengths refract by different amounts; violet slows down and bends the most.

What characterizes a Converging (Convex) Lens?

It is thicker in the middle than at the edges and causes parallel rays of light to converge at the principal focus (F).

What characterizes a Diverging (Concave) Lens?

It is thinner in the middle than at the edges and causes parallel rays of light to diverge as if they were coming from the principal focus (F).

What is a Real Image?

An image formed by the actual convergence of light rays. It can be projected onto a screen and is always inverted relative to the object.

What is a Virtual Image?

An image formed where light rays only appear to originate. It cannot be caught on a screen and is always upright relative to the object.

Define Focal Length (f).

The distance from the optical center of a lens to its principal focus (F).

How is a Magnifying Glass created using a lens?

A converging lens acts as a magnifying glass when an object is placed within the focal length (u < f), producing a virtual, upright, and magnified image.

What is Monochromatic Light?

Light consisting of a single color, meaning it has one specific frequency and wavelength.