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Telescopes (A-level only)

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Question 10

Two telescopes, PPP and QQQ, are designed to observe cosmic sources in different bands of the electromagnetic spectrum:

  • Telescope PPP is an orbital ultraviolet (UV) reflecting telescope with a primary mirror diameter DP=2.5 mD_P = 2.5\text{ m}DP​=2.5 m, operating at an observing wavelength of λP=200 nm\lambda_P = 200\text{ nm}λP​=200 nm.
  • Telescope QQQ is a ground-based single-dish radio telescope with a dish diameter of DQ=75.0 mD_Q = 75.0\text{ m}DQ​=75.0 m, operating at an observing wavelength of λQ=3.0 cm\lambda_Q = 3.0\text{ cm}λQ​=3.0 cm.

Perform the following analyses:

a.

Calculate the ratio of the collecting power of Telescope QQQ to Telescope PPP.

[2]
b.

Calculate the minimum angular resolution (using θ≈λD\theta \approx \frac{\lambda}{D}θ≈Dλ​) for both telescopes, and determine which telescope can resolve finer spatial details.

[3]
c.

Contrast their structural design and positioning by stating one similarity in their structural design and explaining one difference in their positioning requirements.

[2]
Markscheme

Telescopes (A-level only) Questions

  1. A Level
  2. /Physics
  3. /Telescopes (A-level only)

18 exam-style questions on AQA A Level Physics Telescopes (A-level only), covering Astronomical telescope consisting of two converging lenses (A-level only), Reflecting telescopes (A-level only), Single dish radio telescopes, I-R, U-V and X-ray telescopes (A-level only), and Advantages of large diameter telescopes (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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