Question

Two stars are situated at a distance of 8 light years from the earth. These are to be just resolved by a telescope of diameter 0.25 m. If the wavelength of the light used is 5000 a, then the distance between the stars must be

Answer 1

The distance between the stars is 1.95 x 10`11m.

Time = 8 Light years (Given)

Diameter of the telescope = 0.25m (Given)

Wavelength of the light = 5000a (Given)

Thus,

Limit of the resolution of telescope -

α = 1.22λ / a = d/x

d = 1.22λx / a

= 1.225 × 5 × 10`7 × 8 × 10`16/ 0.25

= 1.95 x 10`11

Therefore, the distance between the stars is 1.95 x 10`11m.