DP Chemistry (last assessment 2024)
Question 20N.3.hl.TZ0.14b
| Date | November 2020 | Marks available | [Maximum mark: 1] | Reference code | 20N.3.hl.TZ0.14b |
| Level | hl | Paper | 3 | Time zone | TZ0 |
| Command term | Explain | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 1]
20N.3.hl.TZ0.14b
(b)
Doping of silicon increases the conductivity in semiconductors.
Explain how doping improves the conductivity of silicon.
[1]
Markscheme
electrons and holes flow in opposite directions
OR
electrons can flow into holes
OR
gap between valence and conduction bands becomes smaller ✔
Examiners report
The better candidates were able to explain how doping improves the conductivity of silicon and typically stated that electrons can flow into holes. The weaker candidates had some idea of what was involved but often were not able to articulate precisely in a scientific manner the process and hence usually failed to score the mark.
