Question 18M.3.HL.TZ1.7
| Date | May 2018 | Marks available | [Maximum mark: 6] | Reference code | 18M.3.HL.TZ1.7 |
| Level | HL | Paper | 3 | Time zone | TZ1 |
| Command term | Calculate, Explain | Question number | 7 | Adapted from | N/A |
An observer A is on the surface of planet X. Observer B is in a stationary spaceship above the surface of planet X.
Observer A sends a beam of light with a frequency 500 THz towards observer B. When observer B receives the light he observes that the frequency has changed by Δf.
Observer B then sends a signal with frequency 1500 THz towards observer A.
Calculate the shift in frequency observed by A in terms of Δf.
[2]
Δf f
therefore the change is «–»3Δf
[2 marks]
Calculate the gravitational field strength on the surface of planet X.
The following data is given:
Δf = 170 Hz.
The distance between observer A and B is 10 km.
[2]
g = «c2 =» (3 × 108)2
g = 3.1 «ms–2»
If POT mistake, award [0].
Award [2] for BCA.
[2 marks]
Observer A now sends a beam of light initially parallel to the surface of the planet.
Explain why the path of the light is curved.
[2]
the mass of the planet warps spacetime around itself
the light will follow the shortest path in spacetime «which is curved»
[2 marks]