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1CP2-P-9.6 Bitmap sound and compression checkpoint

Part 6 of 6 · 1CP2-P-9 · Bitmap, sound and compression

This checkpoint assesses P-9 only. Show formulae, working and units. Keep pixel dimensions separate from bit size, and sample rate separate from sample interval.

Students will:

  • apply bitmap and sound size calculations with working and units
  • keep dimensions separate from storage size
  • explain sampling and colour-depth effects
  • recommend compression from the need for exact reconstruction

Inside: 3 explanation cells, 1 fill-in-the-blanks cell, 3 multiple-choice questions and 6 written answers. 20 marks, about 45 minutes.

Series: 1CP2-P-9 · Bitmap, sound and compression, part 6 of 6.

Shared by Coding PathwayVerified teacher

  • 13 cells
  • About 45 minutes
  • CC BY-SA 4.0
  • Shared 17 Aug 2026

Preview

The whole resource, exactly as a class sees it. Answers and marking are held back.

Bitmap, sound and compression checkpoint

This checkpoint assesses P-9 only. Show formulae, working and units. Keep pixel dimensions separate from bit size, and sample rate separate from sample interval.

Fill in the blanks3 marks
Image bits = width × height × colour gap 1. Sound bits = sample rate × bit depth × gap 2. Exact reconstruction requires gap 3 compression.
  • depth
  • duration
  • lossless
Multiple choice1 mark

How many colours can 6 bits per pixel represent?

  • A6
  • B12
  • C32
  • D64
Written answer2 marks

A bitmap is 40 × 30 pixels. Calculate its pixel count and explain why this is not yet its file size.

Give the pixel unit and identify the missing factor.

Students type their answer here.

Written answer3 marks

Calculate the uncompressed size in bits and bytes of a 32 × 16 bitmap using 4-bit colour.

Show both stages.

Students type their answer here.

Written answer3 marks

Explain one quality and one storage effect of increasing bitmap colour depth.

Link more codes per pixel to both outcomes.

Students type their answer here.

Sound representation

Sampling analogue soundanalogue waveform (blue); regular samples (orange)sample rate = samples each second; interval = time between samples

The analogue signal is sampled at regular intervals. Each measured amplitude is rounded to one of the levels allowed by bit depth and stored as a binary code.

Written answer2 marks

Describe how analogue sound is converted into a digital representation.

Give the central stages in order.

Students type their answer here.

Written answer2 marks

Calculate the size in bits of 4 seconds of mono sound at 2000 samples/s and 8 bits/sample.

Show the formula and unit.

Students type their answer here.

Multiple choice1 mark

Which change captures waveform changes more frequently?

  • AHigher sample rate
  • BHigher bit depth only
  • CLonger filename
  • DLossless licence
Written answer2 marks

A website must send photographs quickly, and a small visible quality reduction is acceptable. Recommend a compression category and justify it.

Use acceptable loss and transfer size.

Students type their answer here.

Multiple choice1 mark

Which calculation uses binary storage multiples correctly?

  • A8192 bits ÷ 8 = 1024 bytes = 1 KiB
  • B8000 bits = 1 KiB
  • C1024 bits = 1 KiB
  • D1000 bytes = 1 KiB exactly

Route forward

You have completed bitmap, sampled-sound and compression representation. Teachers should now mix these calculations with off-platform examination questions so method and units remain fluent.