How devices use waves to send and capture information and energy
Grade 11 Science Worksheet
Circle the best answer, or write your answer on the line.
An ultrasound pulse returns from a boundary in a gel test block after 130 μs. The scanner assumes 1540 m/s. How deep is the boundary, to 0.01 cm, Ari?
An ultrasound pulse returns from a boundary in a gel test block after 78 μs. The scanner assumes 1540 m/s. How deep is the boundary, to 0.01 cm, Bo?
An ultrasound pulse returns from a boundary in a gel test block after 200 μs. The scanner assumes 1540 m/s. How deep is the boundary, to 0.01 cm, Esme?
Read this first
Use this
The scanner assumes sound travels 1540 m/s.
In the signal strip, about how deep is the boundary whose echo returns after 52 μs, Jun?
- About 52 cm
- About 8 cm
- About 4 cm
In the signal strip, why does one echo arrive later than the other, Kira?
Use the picture in question 4.
- It came from deeper down
- It was a much louder echo
- It traveled faster
In the signal strip, why does the scanner halve each echo time, Luz?
Use the picture in question 4.
- Sound slows down by half in the gel
- Half the echo is lost
- The pulse goes down and back
A panel is 20% efficient. What does that mean, Pia?
- It works 20% of the day
- It turns 20% of the light into electricity
- It lasts 20 years
Why do phones use radio waves rather than visible light to reach a tower, Ren?
- Radio passes through walls
- Radio is faster than light
- Light can't carry bits
Why do different radio stations and phones use different frequencies, Tala?
- So they use less battery
- So some travel faster
- So their signals don't mix
Why does a digital call stay clear even with a little noise, Zee?
- Noise can't reach radio waves
- The phone turns the noise up
- Bits are read as 0 or 1
