Light：練習題

Which of the following is a primary source of light?

A student places a small object between two plane mirrors that are fixed at an angle of \(90^{\circ}\) to each other. How many images of the object can the student see in total within the mirrors?

A ray of light strikes a plane mirror at an angle of incidence of \(35^{\circ}\). If the mirror is then rotated by \(10^{\circ}\) around the point of incidence in a direction that increases the angle of incidence, what is the new angle between the incident ray and the reflected ray?

In a dark room, if you shine a torch on a solid wooden block, what is formed on the wall behind the block?

If the distance between a light source and an opaque object is doubled, while the screen remains in the same place, what happens to the area of the shadow cast on the screen?

When light hits a smooth, shiny surface like a mirror, it bounces off. What is the name of this process?

Explain why we can see a non-luminous object, such as a book, even though it does not produce its own light.

Why do we see a flash of lightning before we hear the sound of thunder during a storm?

Light
A student conducts an experiment with a flashlight and a mirror.
(a) State the Law of Reflection regarding the angle of incidence and the angle of reflection.
(b) If a ray of light hits a mirror at an angle of \(25^{\circ}\) to the normal, what is the angle of reflection?
(c) Explain the difference between a translucent material and a transparent material in terms of how much light passes through.

Light
A student investigates how light travels and interacts with different surfaces. They use a laser pointer and a series of mirrors and blocks.

(a) The student shines the laser at a plane mirror. If the angle between the incident ray and the mirror surface is \(30^{\circ}\), what is the angle of reflection? (Hint: The angle is measured from the normal).
(b) The student then places a block of glass in the path of the light. The light appears to bend as it enters the glass. Name this process and explain why it happens.
(c) If the student replaces the glass with a piece of black felt, what happens to the light? Use the term absorption.