W1 Vergence and Refraction

What happens to wavefronts at infinity?

Wavefronts are flat

What is the direction of light?

Left to right

What is vergence?

Describes the path/curvature of the pencil of light rays- whether they’re converging or diverging

What is the relationship between wavefronts and vergence?

The more curved the wavefront greater the vergence

What is the focus in a converging pencil?

The point at which the rays of light meet and the image forms

What is the refractive index of air?

1.00

What do we assume about the direction of light?

That it’s travelling from left to right

What other assumptions do we make?

Objects will always be on the left of a reflective/refractive boundary and we always measure FROM the reflective/refractive boundary

How do we obtain a positive numerical value of distance (l)?

If the distance from the boundary to the light source/object is measured in the same direction of light then the value is positive (convergence)

How do we obtain a negative numerical value of distance (l)?

If the distance from the boundary to the light source/object is measured in the opposite direction of light (right to left) then the numerical value of distance is negative (divergence)

What is image vergence?

The vergence of the light rays after experiencing the refractive boundary

What factors impact refractive index?

The wavelength of light- high refractive index materials are typically more dense

What is the normal?

The angle perpendicular to the surface- refraction cannot occur when light rays fall on the normal

How does velocity change?

Depending on the change in refractive indexes between optical mediums

What is Snell’s law?

The ratio of the sine of the angle of incidence to the sign to the angle of refraction is constant

What is the difference between angle (i) and angle (I’)?

Angle (I) is angle of incidence angle (I’) is angle of refraction

What happens if the secondary medium (n’) has a higher refractive index than the primary medium (n)?

Secondary medium is more dense so light ray moves towards the normal and vice versa