State Snell's law.

Define refractive index in terms of light speed.

Light enters glass \((n=1.50)\) from air at \(30^\circ\). Find the refracted angle.

Find the speed of light in water with \(n=1.33\).

When light enters a medium with larger refractive index, does it bend toward or away from the normal?

When light crosses a boundary, which quantity stays the same: speed, wavelength, or frequency?

A vacuum wavelength is \(600\,\mathrm{nm}\). Find the wavelength in glass with \(n=1.50\).

Light goes from glass \((n=1.50)\) to air at \(30^\circ\). Find the refracted angle.

Why must refraction angles be measured from the normal?

A ray in air enters a medium and bends to \(20^\circ\) from the normal when the incident angle is \(40^\circ\). Find the medium's refractive index.

Why does a pencil in water appear bent at the water surface?

Find the frequency of light with vacuum wavelength \(500\,\mathrm{nm}\).

The light from the previous question enters glass with \(n=1.50\). What is its frequency in glass?

For small angles, derive an approximate refraction relation from Snell's law.

A light ray enters a slab with parallel faces. How does the outgoing ray direction compare with the incoming ray direction?

Why is a refractive index usually greater than 1 for transparent materials?

A ray goes from medium 1 to medium 2 without bending despite crossing the boundary. Give two possible reasons.

A ray in medium \(n_1\) refracts into medium \(n_2\). If \(n_2<n_1\), what happens to the refracted angle before total internal reflection occurs?

Explain why wavelength changes but frequency does not when light enters a new medium.

Use Fermat's principle qualitatively to justify bending toward the normal in a slower medium.