Question 22M.2.SL.TZ1.d.ii
Date | May 2022 | Marks available | [Maximum mark: 3] | Reference code | 22M.2.SL.TZ1.d.ii |
Level | SL | Paper | 2 | Time zone | TZ1 |
Command term | Determine | Question number | d.ii | Adapted from | N/A |
The missing section of insulation is 0.56 m long and the external radius of the pipe is 0.067 m. The emissivity of the pipe surface is 0.40. Determine the energy lost every second from the pipe surface. Ignore any absorption of radiation by the pipe surface.
[3]
use of where T = 357 K ✓
use of « = 0.236 m2» ✓
P = 87 «W» ✓
Allow 85 – 89 W for MP3.
Allow ECF for MP3.
Candidates at both levels were able to recognize that this was a blackbody radiation question. One common mistake candidates made was not calculating the area of a cylinder properly. It is important to remind candidates that they are expected to know how to calculate areas and volumes for basic geometric shapes. Other common errors included the use of T in Celsius and neglecting to raise T ^4. Examiners awarded a large number of ECF marks for candidates who clearly showed work but made these fundamental errors.

