#### Two stars are 10 light years away from the earth.  They are seen through a telescope of objective diameter 30 cm.  The wavelength of light is 600 nm.  To see the stars just resolved by the telescope, the minimum distance between them should be (1 light year = 9.46 × 1015m) of the order of : Option 1) 106 km Option 2) 108 km Option 3) 1011 km Option 4) 1010 km

As we learnt in

Astronomical Telescope -

- wherein

= focal length of objective

focal length of eyepiece

Here

Resolution of a telescope

Correct optio is 2.

Option 1)

106 km

This is an incorrect option.

Option 2)

108 km

This is the correct option.

Option 3)

1011 km

This is an incorrect option.

Option 4)

1010 km

This is an incorrect option.