17. In Einstein's theory of gravity, light passing a star of mass M, at a distance R from the centre of the star, is bent by an angle (measured in radians, 27 radians = 360) as shown in the diagram. (a) Assume that depends on the gravitational constant G and also depends on the mass of the star M, the distance R and the speed of light c = 3 108 ms , as 0=XGM Rc7, where A is an undetermined dimensionless constant. By considering the dimensions of these quantities determine a, 3 and y. (b) In SI units the numerical value of G is 6.67 x 10-11 Neglecting any spatial extent to the star, and taking A = 1 and M = 2 100 kg, determine the distance R such that light is bent so much that it falls directly into the star. M O R [4] [3]