| Date | May 2017 | Marks available | 2 | Reference code | 17M.3.HL.TZ1.6 |
| Level | Higher level | Paper | Paper 3 | Time zone | Time zone 1 |
| Command term | Explain | Question number | 6 | Adapted from | N/A |
Question
In an experiment a source of iron-57 emits gamma rays of energy 14.4 ke V. A detector placed 22.6 m vertically above the source measures the frequency of the gamma rays.
Calculate the expected shift in frequency between the emitted and the detected gamma rays.
Explain whether the detected frequency would be greater or less than the emitted frequency.
Markscheme
f = «\(\frac{E}{h} = \)» \(\frac{{14\,400 \times 1.6 \times {{10}^{ - 19}}}}{{6.63 \times {{10}^{ - 34}}}}\) = «3.475 × 1018 Hz»
Δf = «\(\frac{{g \times \Delta h \times f}}{{{c^2}}} \approx \)» 8550 «Hz»
[2 marks]
«as the photon moves away from the Earth, » it has to spend energy to overcome the gravitational field
since E = h\(\,\)f, the detected frequency would be lower «than the emitted frequency»
[2 marks]
