Core - Topic 1.2 - Electromagnetic Waves

Question 1

What EM wave has the shortest wavelength?

Answer 1

Gamma

Question 2

Both infrared and ultraviolet rays can have harmful effects on our bodies.
Describe how the harmful effects of these rays are different.
(2)

Answer 2

A description including the following:
• infrared causes burns (to the
skin) /( 'skin) blistering (1)
• (whereas) ultraviolet causes
{cell damage / (skin) cancer
/ sunburn} (1)

Question 3

Infrared is used in an electric toaster.
Infrared is also used by a television remote control.

Explain why using a television remote control does not burn anyone.
(2)

Answer 3

An explanation linking two of the
following points
• wavelength / frequency (1)
• are different (1)
OR
• toaster on for longer (1)
• (so) much more energy (1)

Question 4

Gamma rays can cause cancer.
Gamma rays can also be used to treat cancer.
Explain how gamma rays can do both.
(3)

Answer 4

An explanation linking three of the
following points
• gammas change cell growth /
eq (1)
• (so can) cause uncontrolled
growth (1)
• (but also can) be focussed to
(kill cancer cells)(1)
• without damaging other cells

Question 5

State two uses of gamma radiation.

2

Answer 5

Any two from the following points
• sterilising food (1)
• sterilising medical
equipment(1)
• detection of cancer(1)
• treatment of cancer(1)

Question 6

Stars can emit gamma waves and light waves.
Gamma waves and light waves are both parts of the electromagnetic spectrum.
Explain why it takes the same time for both of these waves to travel from the star
to a space telescope.
(2)

Answer 6

A description including the
following points
• travel at the same speed
(1)
• in a vacuum/space (1)

Question 7

Ultraviolet radiation and infrared radiation are emitted by the Sun and reach the
surface of the Earth.
(i) Describe a harmful effect of ultraviolet radiation.
(2)

Answer 7

A description including two of the
following points
Either
• UV penetrates the skin / can
damage normal cells/ cause
cell mutation/ionise cells (1)
• can cause (skin) cancer /
can cause premature ageing
(1)
OR
• UV penetrates the eye / can
damage/mutate cells in the
eye (1)
• can cause cataracts /
damage to the retina
(macular degeneration) (1)

Question 8

Explain why ultraviolet radiation is likely to be more dangerous to humans
than infrared radiation.
(2)

Answer 8

An explanation linking two of the
following points
• (ultraviolet/it) has a higher
frequency (than infrared)
(1)
• (therefore ultraviolet/it) has
higher (photon) energy (1)
• (ultraviolet/it) penetrates
further /(ultraviolet/it)
causes ionisation (1)

Question 9

Herschel discovered invisible rays beyond one end of the visible spectrum.
Ritter discovered invisible rays beyond the other end of the visible spectrum.
Compare and contrast the two experiments leading to these discoveries.
You may draw labelled diagrams to help with your answer.
(6)

Answer 9

Similarities
• used white light from the Sun
• glass prism
• produced a visible spectrum
(Herschel’s) infrared experiment
• used a thermometer to measure the temperature of different
colours of the visible spectrum
• temperature increased towards the red end
• temperature increased more past the red end of the
spectrum.
• temperature rise was due to invisible rays named infrared
(Ritter’s) ultraviolet experiment
• used silver chloride on paper this slowly turns black in visible
light.
• silver chloride turned black faster as the paper was put at
the violet end of the spectrum
• beyond the violet the silver chloride turned black even more
rapidly
• due to the presence of invisible rays (originally called
chemical rays) now called ultraviolet