The electromagnetic spectrum and its uses
Grade 11 Science Worksheet - Building Confidence
Circle the best answer, or write your answer on the line.
Ari tunes a radio to 100 MHz. What is the wavelength of the signal?
Esme listens to an AM station at 600 kHz. What is the wavelength of the signal?
Green light is 550 nm and red light is 700 nm. Which has the higher frequency, and about what is it, Kira?
- Green, about 5.5 × 10¹⁴ Hz
- Green, about 5.5 × 10¹¹ Hz
- Red, about 4.3 × 10¹⁴ Hz, since longer waves have higher frequency
- Both the same, since light has one speed
The microwave band runs from about 1 mm to 30 cm. Where does a 12 cm wave fall, and what is its frequency, Luz?
- In the radio band, since 12 cm is longer than 1 mm
- Inside the microwave band, at about 36 MHz
- Inside the microwave band, at about 2.5 GHz
- Inside the microwave band, at about 2.5 MHz
Why can X-rays show a broken bone through skin when visible light cannot, Milo?
- X-rays are brighter than visible light, so they show more
- X-ray photons pass through soft tissue; bone absorbs them
- X-rays travel faster than visible light through skin
- Bones glow when X-rays hit them, lighting the picture
Why can ultraviolet sunburn skin when visible light of the same brightness does not, Noah?
- UV is a hotter kind of light than visible light is
- UV travels faster than visible light, so it hits harder
- UV has longer wavelengths, so each photon carries more energy
- Each UV photon carries more energy, enough to damage skin cells
Why can Wi-Fi pass through a wall, but a TV remote's infrared cannot, Pia?
- Wi-Fi has more energy per photon than infrared
- Radio waves travel faster than infrared, so they get through
- Infrared is too bright to pass through a wall
- Walls let 12 cm radio waves through but block infrared
A radio signal and a flash of light leave the Moon together, 384,400 km away. Which arrives first, Ren?
- The light, since its frequency is higher
- They arrive together, after about 1.3 s
- They arrive together, after about 1.3 minutes
- The radio signal, since its wavelength is longer
In a vacuum, a wave's frequency doubles. What happens to its wavelength, Tala?
- It quadruples, because λ goes as f²
- It halves, because the speed stays fixed
- It stays the same, because it is the same kind of wave
- It doubles, because the wave speeds up
Wi-Fi works at 2.4 GHz and at 5 GHz. Which has the longer wavelength, and by about how much, Zee?
- 5 GHz, by a factor of about 2
- 2.4 GHz, by a factor of about 2
- 2.4 GHz, by a factor of about 2.4
- Neither: they both travel at c