a) Calculate the energy corresponding to the Gamow peak for proton-proton fusion at T = 108K. b) Describe the PP chains in stars. c) Consider elastic scattering of electrons by a nucleus with charge distribution given by if r Ri, Pe(r) = = p/2 0 if Ri Ro, where r represents the radial distance from the centre of the nucleus. Calculate the form factor of the process. d) Consider two nuclei 2i4X2i+1 and 2, where i is a positive integer number. According to the semi-empirical mass formula for the binding energy, which one has larger binding energy? Justify your answer.

Use the semiempirical mass equation to compute, for given A, the relation between Z and N for a nucleus that has Sn 4 0 (the neutron "drip line"). Compute N/Z for A 4 100.

5 Answer the following questions: a) For a homogeneous nucleation process, sketch the dependence of the surface and bulk free energies on the radius of a spherical embryo using the equation below. kT AG, = 4rv*y -* inS V, AG > r b) Sketch the dependence of the free energy changes (AG,) on the radius of a spherical embryo when the supersaturation ratio (S) is greater than 1, equal to 1 and less than 1. AG c) Discuss the importance of supersaturation on precipitation

A 2-stage rocket is fired from rest. Its acceleration data are shown in the graph below. Plot the v-t and s-t graphs describing the motion of the rocket-clearly showing the shape of the curve (or add a note) and values at inflection points. Show any calculations as well. Then find the velocity of the rocket and its elevation after 20 seconds of flight. a (m/s?) 25 18 (s) 15 20