Waves and Properties of Light

Properties of waves, including light and sound

Properties of waves

Textbook P14

pages 561

General wave properties

• Waves transfer energy without transferring matter

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• speed: time taken for one complete wave; the rate of motion (distance/time) of an object

• frequency: the number of waves passing a fixed point in a given amount of time

• wavelength: the distance between a point on one wave to the same point on the next wave

• amplitude: the distance between the maximum position to the undisturbed position

​rarefaction compression

Multiple Choice

What do all waves transmit?

• matter

• energy

• water

• sound

Multiple Choice

What is the distance between two consecutive points in phase on a wave called?

• frequency

• period

• amplitude

• wavelength

Multiple Choice

The number of waves produced in a given amount of time is the wave's ________.

• amplitude

• wave speed

• wave length

• frequency

Multiple Choice

What type of wave is a sound wave?

• transverse

• Doppler

• longitudinal

• heard

Multiple Choice

Transverse waves have crests and troughs. Longitudinal waves have:

• reflections and echoes

• compressions and rarefactions

• dopplers and diffractions

• anvils and stirrups

Light

Textbook P13

pages 541

Reflection of Light

Exercise

A bottle is placed 5 cm in front of a plane mirror. Draw an accurate scale diagram, and use it to show that the image of the lamp is 5 cm behind the mirror.

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Need: graph paper and protractor

Refraction of Light

_{reflection vs refraction}

• reflection – waves bounce off an object, reflected at a plane surface   

• refraction – waves pass across a boundary between 2 substances of different medium which have different density hence the waves change its speed causes it to change direction

• v = fλ, where v is the speed of sound, f is its frequency, and λ is its wavelength 

Multiple Choice

We see shadows because light travels in a __________________ line.

• curved
• straight
• rainbow

Multiple Choice

When light bounces back it is _____

• Reflected

• Refracted

• Absorbed

• Optical Density

Multiple Choice

Why does the straw appear to be bent?

• light is reflected

• light is absorbed

• light is turned

• light is refracted

​https://ophysics.com/l12.html

​HOW LENS WORK?

Thin Converging Lens

Multiple Choice

The point at which rays parallel to the optical axis meet is called the ____________________________.

• focal point

• virtual point

• real point

• optic point

Spectra

Textbook P15

pages 575

speed of em waves in a vacuum is 3.0 x 10⁸ m/s

Multiple Choice

The visible light spectrum ranges between

• radar waves and X-rays.

• television waves and infrared rays.

• infrared rays and ultraviolet rays.

• ultraviolet rays and gamma rays.

Multiple Choice

The waves with the longest wavelengths in the electromagnetic spectrum are

• Infrared rays.

• radio waves

• gamma rays

• X-rays

Multiple Choice

Infrared rays have a shorter wavelength than

• Ultraviolet ray.

• X-rays.

• radar waves.

• gamma rays

Multiple Choice

Radio waves and _______ are used in communication

• Microwaves

• Gamma rays

• Visible light

• Ultraviolet

Multiple Choice

An electromagnetic wave in a vacuum has a wavelength of 0.07m. What is its frequency?

• f= 3.0x 10^8 m/s

• f= 3.0x 10^9Hz

• f=4.3x 10^9Hz

• f=4.3x 10^8m/s

Sound

• sound is produced by vibrating sources

• longitudinal; compressions and rarefactions

• audible f 20 - 20000Hz

• medium is needed to transmit sound waves

• sound travels fastest in solid, then liquid then gas

• amplitude-loud, frequency-pitch,

• echo - reflected sound

Sound

Textbook P12

pages 530

Multiple Choice

There is no sound in space.

• true

• false

Multiple Choice

Which statement best explains why thunder is heard after lightning is seen?

• light travels faster than sound

• light travels slower than sound

• thunder is produced by the impact of lightning against the ground

• the eye works faster than the ear

Multiple Choice

Two sound waves are produced by a clarinet. Both sound waves have the same pitch, but the second one is louder. Which of the following properties is greater for the second sound wave?

• frequency

• amplitude

• wavelength

• speed in air

Multiple Choice

In which medium would sound move the fastest?

• vacuum

• air

• water

• steel