What is the law of reflection Law of

What is the law of reflection? Law of Reflection keywords mirror Describe what is happening to the particles in a longitudinal wave such as sound. reflection normal incidence angle The particles in a sound wave are oscillating parallel to the direction of energy transfer.

What is the law of reflection? Law of Reflection Gold • Show the law of reflection using ray diagrams. Silver What is the law of reflection? • Draw ray diagrams to show the path of light. Bronze Learning Objective: • State the meanings of transparent, translucent and opaque.

What is the law of reflection? 5 quick questions 1. What is the approximate speed of sound in air? • The speed of sound wave in air about 330 m/s 2. What do waves transfer: Water Particles Energy Light Sound 3. What type of wave is sound? • Longitudinal 4. What is amplitude? • Amplitude is the maximum disturbance from its undisturbed position. 5. Longitudinal waves travel fastest through which of these material states: Solid Liquid Gas

What is the law of reflection? Transverse Wave • When transverse light waves come into contact with objects, they may behave in different ways. • Objects may be: • Transparent • Translucent • Opaque

What is the law of reflection? Transparent Translucent Opaque • Transparent: • Light will almost completely pass through these objects so they appear see-through. • Translucent: • Light will partly pass through these objects so you will be able to see through them but not with much detail. • Opaque: • Light cannot pass through these objects at all and will either be absorbed or reflected.

What is the law of reflection? Ray Diagrams • When light waves travel, we can draw them as a ray in a ray diagram. • A block with shaded lines represents an object such as a mirror. • A straight line shows a ray of light, whilst an arrow on the line shows the direction. • A small dotted line shows the normal. This is 90 o to the surface. • A second straight line shows a ray of light reflected. This will also have an arrow which shows the direction. Reflection

What is the law of reflection? What is a Medium • Whatever something is travelling through is called its medium. • If you are running on the ground, the air is your medium. • If you are swimming, water is your medium. • Light can travel through all different substances and so its media can change. • For example, sunlight travels through space and then through air as it gets nearer Earth. • It may also have to travel through glass if it travels through the window. Space, air and glass are all media of light.

What is the law of reflection? Speed of Light • The speed of light is very, very fast. In fact, it is the fastest thing in the universe. • However, it can slow down depending on its medium. Light travels fastest in space where there are no particles to get in its way. • It slows down a bit when travelling through the air as this has more particles, which slow it down. • It slows down even more if it enters glass. • The denser the medium, the slower light travels.

What is the law of reflection? Refraction • Refraction is the bending of a light or sound wave. • An example of refraction is when a straw in a glass of water looks like it is bent or broken. • Another example of refraction is a bending of the sun's rays as they enter raindrops, forming a rainbow. • Refraction occurs at the boundary of two media when light travels from one medium into the other and its speed changes but its frequency remains the same. • If the light ray hits the boundary at an angle which is not perpendicular to or parallel to the surface, then it will change direction and appear to `bend'.

What is the law of reflection? Refraction • When a wave like light; changes speed, but the frequency stays the same it refracts. • A simple way to demonstrate this is to shine a ray of light through a glass block at an angle. • The light moves from air to glass so it slows down and changes direction. • It then moves from glass to air so speeds up and changes direction again. Refraction As the light slows down, it refracts towards the normal. When it speeds up, it refracts away from the normal.

What is the law of reflection? 1. What does Translucent mean? • Light will partly pass through these objects so you will be able to see through them but not with much detail. 2. What does Transparent mean? • Light will almost completely pass through these objects so they appear seethrough. 3. What does Opaque mean? • Light cannot pass through these objects at all and will either be absorbed or reflected. 4. What is the speed of sound in air? • The speed of sound in air (at sea level) is 330 m/s. 5. Longitudinal waves travel slowest through which of these material states: Solid Liquid Gas

What is the law of reflection? … w e i Rev Learning objective Gold • Show the law of reflection using ray diagrams. Silver • Draw ray diagrams to show the path of light. Bronze What is the law of reflection? • State the meanings of transparent, translucent and opaque.