Please help with the following Physics questions

1 . (a) State Kirchhoff's laws. [2] ( b ) For the circuit shown in Fig. 1.1, determine the current flowing in each branch of the circuit. [8] 60 V 120 V 50 02 25 0 20 02 Fig. 1.1 2. (a) The various isotopes of an element X are distinguished by using a notation X. Explain the meaning of A, Z and the term isotopes. [3] (b ) The uranium atom, U , has a mass of 235.04393 u. (i) Given that ro = 1.2 x 10" m, estimate the radius of the uranium nucleus. (ii) What is the binding energy of the uranium atom? [7] Data: Mass of proton = 1.00728 u Mass of neutron = 1.00867 u Mass of electron = 0.00055 u lu = 931 MeV