Question
Thermal radiation is part of the electromagnetic spectrum.
What is the name of this region of the spectrum?
A gamma rays
B infrared rays
C ultraviolet rays
D visible light rays
Answer/Explanation
Ans: B
Question
A student is asked to give two uses of four different types of electromagnetic radiation.
In which row are both the uses correct?
| radiation | use 1 | use 2 |
A | radio | sterilising medical equipment | mobile phone masts |
B | microwaves | mobile phones | sterilising medical equipment |
C | infrared | remote controllers | intruder alarms |
D | X-rays | security in airports | intruder alarms |
Answer/Explanation
Ans: C
Question
The diagram shows the electromagnetic spectrum. The numbers indicate the approximate wavelength at the boundaries between the various regions of the spectrum.
For a device to be able to make use of electromagnetic radiation, it needs an aerial of approximately the same size as the radiation it is designed to work with.
Which statement is correct?
A mobile phone uses radiation from region P.
A television satellite dish uses radiation from region Q.
The receptor cells in an eye use radiation from region R.
The remote controller for a television uses radiation from region U.
Answer/Explanation
Ans: B
Question
Which statement about microwaves is correct?
Microwaves are longitudinal waves.
The frequencies of microwaves are greater than the frequencies of visible light.
The speed of microwaves in a vacuum is equal to the speed of visible light in a vacuum.
The wavelengths of microwaves are smaller than the wavelengths of infra-red.
Answer/Explanation
Ans: C
Question
Bats produce ultrasound waves to navigate.
What is a possible frequency range for these waves?
A 0–20 Hz B 20 Hz–2000 Hz C 2kHz–20 kHz D 20 kHz–120 kHz
Answer/Explanation
Ans: D
Question
An intruder alarm sensor detects that a person is warmer than his surroundings.
Which type of electromagnetic wave does the sensor detect?
infrared
radio
ultraviolet
visible light.
Answer/Explanation
Ans: A