Digital information: bits, sampling and storage

Answer Key - Grade 11 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   A drive holds 1 TB (1 TB = 10¹² bytes). How many GiB is that (1 GiB = 2³⁰ bytes), to 0.01, Ari?

   931.32 GiB
2. 2.

   A drive holds 4 TB (1 TB = 10¹² bytes). How many GiB is that (1 GiB = 2³⁰ bytes), to 0.01, Esme?

   3725.29 GiB
3. 3.

   A photo is 4000 × 3000 pixels, with 3 bytes per pixel. How big is it before compression, Jun?

   • 4 MB
   • 12 MB
   • 36 MB
4. 4.

   Each pixel uses 24 bits. How many different colors can a pixel show, Kira?

   • 24
   • About 16.8 million
   • 48
5. 5.

   A photo file is squeezed to one-tenth of its size with lossy compression. What has happened, Luz?

   • The photo became ten times bigger on screen
   • Its colors turned gray
   • Some hard-to-see detail was dropped
6. 6.

   Milo says a 1 TB drive should show 1000 GiB. Agree or disagree?

   • Agree: GB and GiB are the same size
   • Disagree: it is about 931 GiB
   • Agree: tera means 1000 giga either way
7. 7.

   Noah says doubling the bits per sample doubles the number of loudness levels. Agree or disagree?

   • Agree: bits add levels one at a time
   • Agree: twice the bits, twice the levels
   • Disagree: it squares them
8. 8.

   Pia says digital files last forever on a drive. Agree or disagree?

   • Agree: bits can't wear out
   • Agree: files copy themselves
   • Disagree: drives fail, so back up
9. 9.

   A sound of 30,000 Hz is recorded at 44,100 samples a second. Is it captured faithfully, Ren?

   • Yes: any sampling rate works
   • Yes: 44,100 is bigger than 30,000
   • No: it needs over 60,000 a second
10. 10.

    A voice recorder samples 8,000 times a second. About what is the highest pitch it can hold, Tala?

    • About 8,000 Hz
    • About 16,000 Hz
    • About 4,000 Hz