Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Refraction is the bending of light as it passes from one transparent medium to another, such as from to or .
Light changes direction because it changes speed when entering a medium with a different density. For example, light travels slower in than in .
When light enters a denser medium at an angle, it bends towards the 'normal' (an imaginary line at to the surface).
White light is actually made up of a mixture of seven colors: , , , , , , and ().
Dispersion is the process where white light is split into its constituent colors using a prism. This happens because different colors of light bend by different amounts; light bends the least, while light bends the most.
A rainbow is formed by the refraction, reflection, and dispersion of light in water droplets, which act like tiny prisms.
📐Formulae
💡Examples
Problem 1:
A pencil is placed in a glass of water. From the side, the pencil appears to be broken or shifted at the water's surface. What causes this effect?
Solution:
Refraction of light.
Explanation:
As light reflects off the pencil and travels from the (more dense) into the (less dense), it speeds up and bends away from the normal. Our eyes trace these rays back in a straight line, making the submerged part of the pencil appear to be at a different position than it actually is.
Problem 2:
Which color of the visible spectrum is refracted the most when passing through a glass prism?
Solution:
Explanation:
Each color in white light has a different wavelength. light has a shorter wavelength and slows down more than light when entering the glass, causing it to bend (refract) at a sharper angle.