If Sun acted as a Gravity lens bending light 1.73 sec,where would the focus be?

Question

How far from the sun would the light rays converge?

Answer 1

What you are saying is that light waves passing by the surface of the Sun are all deflected towards the Sun's center by 1.73 arcseconds and where do all these deflected rays cross? In this type of problem, it makes sense to express the angle in radians. There are 206,000 arcseconds per radian so the deflection is 8.4 x 10^-6 radians. The ratio of the Sun's radius to the distance to the focus is the deflection in radians (more precisely the tangent of the angle but that's the same thing here). The Sun's radius is 431,000 miles. The focus then is at:

431,000 miles / 8.4 x 10^-6 = 51,000,000,000 miles or about 17 times the distance to Neptune.