Electromagnetic waves

Which row identifies features of a light wave ?

All objects emit electromagnetic waves.

Thermal imaging cameras detect some electromagnetic waves. The photograph is a thermal image of an animal taken using a thermal imaging camera at night.

Which type of electromagnetic wave is the animal emitting?

Tick (✓) one box.

Why is a human not able to see the animal at night?

State one reason why ultraviolet, X-ray and gamma radiation can be harmful to living things.

Ultraviolet, X-ray and gamma radiation are also useful.

Draw one line from each type of electromagnetic wave to a typical use.

Security markings can be written on items you own. These are written using a fluorescent ink which is only visible under an ultraviolet lamp.

The diagram shows a security code ABCXYZ written on a black surface.

Particles inside the atoms in the ink absorb energy from ultraviolet radiation.

The same particles inside the atoms in the ink re-emit the energy as waves in the visible light region of the electromagnetic spectrum.

Which particles inside the atom absorb ultraviolet radiation and emit visible light?

Describe what happens to these particles when they absorb ultraviolet radiation.

Electromagnetic waves with short wavelengths can cause ionisation when absorbed by these particles inside the atom.

Describe the effect ionisation has on the atom.

Radio waves and microwaves are both electromagnetic waves.

Describe the difference in frequency between radio waves and microwaves.

Describe one use that radio waves and microwaves have in common.

This question is about electromagnetic waves.

Electromagnetic waves are transverse waves.

Describe what a transverse wave is.

You can label the diagram of a transverse wave to help explain your answer.

A radio wave has a frequency of 7 500 kHz and a wavelength of 40 m.

Calculate the speed of this radio wave.

Use the equation: wave speed = frequency wavelength

Give your answer in metres per second.

Speed =........ m / s

The table shows some different radio waves.

What is the relationship between frequency range and wavelength?

Use the table.

Which type of radio wave has a frequency of 15 MHz and a wavelength of 20 m?

Tick (✓) one box.

High frequency radio waves are similar to microwaves.

Suggest how high frequency radio waves can harm the human body.

Complete the sentence about high frequency radio waves.

High frequency radio waves are more / less dangerous than microwaves.

Suggest a reason for your answer.

Wave X and wave Y are two electromagnetic waves in space.

The frequency of wave X is double the frequency of wave Y.

Which answer describes the wavelength of wave X ?

A Double the wavelength of wave Y

B Half the wavelength of wave Y

C Quadruple the wavelength of wave Y

D The same as the wavelength of wave Y

15* A student shines a ray of white light from air into a glass prism.

White light is made up of many different colours of light. The diagram shows the path of four of these colours of light in the prism.

The speed of these four colours of light in air is 3.0 10⁸ m / s.

The table shows the wavelengths and the speeds of these four different colours of light in the glass prism.

Colour	Wavelength in glass prism (nm)	Speed in glass prism (m / s)
Red	640	1.986 108
Yellow	589	1.984 108
Blue	486	1.976 108
Violet	434	1.971 108

Describe:

• what the student sees when the light travels into the glass prism

• the relationship between the wavelengths of the four different colours of light and their speeds in the glass prism.

Explain your answer using the data in the table and ideas about refraction.

The frequency of electromagnetic waves can be written as 1 × 10^N Hz. 17 N is an integer (a whole number).

The graph shows the typical values of N for different electromagnetic waves.

Which electromagnetic wave has the highest frequency?

Which electromagnetic wave is the most dangerous?

Ultraviolet waves have a greater frequency than visible waves.

How many times greater?

10² 10³ 10¹³ 10¹⁴ 10¹⁶

What is the frequency of a typical radio wave on the graph?

Write your answer as an ordinary number without standard form.

Which sentence is true about electromagnetic waves? Tick (✓) one box.

A 0.8 kW microwave oven is used to cook food. The microwave oven transfers 0.56 kWh when it is used to cook food.

Calculate the time the microwave oven is used for.

Use the equation: energy transferred = power × time

The frequency of electromagnetic waves can be written as 1 × 10^N Hz. 12 N is an integer (a whole number).

The graph shows the typical values of N for different electromagnetic waves.

Which electromagnetic wave has the highest frequency?

Which electromagnetic wave is the most dangerous?

Ultraviolet waves have a greater frequency than visible waves.

How many times greater?

10² 10³ 10¹³ 10¹⁴ 10¹⁶

What is the frequency of a typical radio wave on the graph?

Write your answer as an ordinary number without standard form.

Which sentence is true about electromagnetic waves?

Tick (✓) one box.

A 0.8 kW microwave oven is used to cook food. The microwave oven transfers 0.56 kWh when it is used to cook food.

Calculate the time the microwave oven is used for.

Use the equation: energy transferred = power × time

A satellite receiver can be used to watch television channels. It works using a remote control.

Channel 4 uses a wave with a frequency of 1.0714 × 10¹⁰ Hz. (a)

The speed of the wave is 3.0 × 10⁸ m / s.

Calculate the wavelength of the wave.

Use the equation: wave speed = frequency × wavelength Give your answer to 3 decimal places.

The remote control emits infra-red or radio waves when a button is pressed.

The remote control also contains a light which flashes when a button is pressed.

Explain why the light is needed to show when a button is being pressed.

A student uses a smart meter to check their energy use at home.

The student thinks they can save energy by unplugging their satellite receiver from the mains supply for 8 hours at night.

Calculate the amount of energy saved by unplugging the receiver compared to switching the receiver off for 8 hours at night. Use the Data Sheet.

Give your answer in kWh.

The government wants all homes to have a smart meter by 2024.

Describe how smart meters may change the way energy resources are used. Use your answer to (c)(i).

Radio waves are electromagnetic waves and are used for communications.

Suggest why gamma rays are not used for communications.

Name one other electromagnetic wave that is used for communications.

State one use of this electromagnetic wave in communications.

A TV transmitter emits electromagnetic waves with different frequencies.

Table 15.1 gives information about the waves emitted.

Using data from Table 15.1 describe the relationship between frequency and wavelength.

How many significant figures are used in each value in Table 15.1 ?

Calculate the speed of the wave ARQ B.

Use the equation: wave speed = frequency × wavelength

Speed =........ m / s

A TV transmitter has a useful output energy transfer of 100 kJ in 1 second.

The input energy is 250 kJ in 1 second.

Calculate the efficiency of the TV transmitter.

Some waves are transverse. Some waves are longitudinal.

Which row in the table is correct?

Which property is the same for all electromagnetic waves in space?

A Frequency

B Time period

C Velocity

D Wavelength

Radio waves are electromagnetic waves and are used for communications.

Suggest why gamma rays are not used for communications.

Name one other electromagnetic wave that is used for communications.

State one use of this electromagnetic wave in communications.

A TV transmitter emits electromagnetic waves with different frequencies.

Table 11.1 gives information about the waves emitted.

Using data from Table 11.1 describe the relationship between frequency and wavelength.

How many significant figures are used in each value in Table 11.1 ?

Calculate the speed of the wave ARQ B.

Use the equation: wave speed = frequency × wavelength

Speed =........ m / s

A TV transmitter has a useful output energy transfer of 100 kJ in 1 second.

The input energy is 250 kJ in 1 second.

Calculate the efficiency of the TV transmitter.

Electromagnetic waves have similar properties.

Use these words to complete the sentences:

You can use each word once, more than once, or not at all.

Acceleration Frequency Longitudinal

Sound Speed Transverse Wavelength

Electromagnetic waves are …………………………. waves.

Electromagnetic waves travel with the same …………………………. in space.

A student wants to work out the speed of water waves in a ripple tank. Fig. 13.1 shows the apparatus the student uses.

Name the two extra pieces of apparatus she will need to work out the speed of the waves.

Which statement describes what human eyes can detect?

A Limited range of electromagnetic waves.

B Limited range of sound waves.

C Wide range of electromagnetic waves.

D Wide range of sound waves.

Electromagnetic waves are usually divided into seven different groups.

This diagram of the electromagnetic spectrum is incomplete.

Complete the diagram by adding the missing parts of the electromagnetic spectrum.

Sound is not part of the electromagnetic spectrum.

Explain why.

All waves have a frequency.

Which part of the electromagnetic spectrum has the highest frequency?

What happens to the wavelength of an electromagnetic wave as the frequency increases?

Tick (✓) one box.

Describe how X-rays and gamma rays can damage humans.

A student refracts light with a rectangular glass block.

He looks for a relationship between angle of incidence and angle of refraction.

Suggest how the student completes this experiment and the apparatus he uses.

The student needs to write a risk assessment for the experiment.

Complete the table to give one risk, the hazard it could cause and a control measure for the

The table shows the results from the experiment.

What could the student conclude from the graph?

The angle of refraction at 40° is incorrect.

Use the curve of best fit on the graph to estimate the actual angle of refraction at 40°.

Another student uses red light in the experiment.

She then repeats the experiment with blue light.

Describe and explain the difference in the refraction of the red light and blue light.

Which of these electromagnetic waves has the smallest wavelength?

A Gamma-ray

B Micro-wave

C Radio wave

D X-ray

How are radio waves produced?

A By alternating currents

B By a radio

C By a speaker

D By steady currents