Essential GCSE Physics 44.4

A young astronomer has a telescope with a 6.0cm diameter lens, and uses it to take pictures using visible light (wavelength =500nm). The main factor causing blurring in a good telescope is diffraction.

If a professional astronomer wanted images just as precise using 30cm radio waves, what diameter of dish would be needed?

tried quite a lot of stuff but IsaacPhyiscs keeps marking it wrong

I got - 36 cm

Reply 1

Eimmanuel

Study Forum Helper

Original post by shash._9

It would be more useful to show what you have tried than the answer that you have gotten.

If you think about it carefully, your answer does not make sense.

A wave of wavelength = 500nm requires 6.0 cm diameter lens to produce visible image.

A new wave of wavelength = 30 cm requires 36 cm diameter lens to produce visible image.

The ratio of wavelength to diameter does not match!

I suspect you did not convert your units correctly.