1. (a) State Kirchhoff's Laws. [2] (b) In Figure 1.1 find: 1. The current in each branch. ii. The power dissipated in the 15W resistor. 8\f2. Two thin lenses, one convex with focal length of magnitude 20cm and the other concave with focal length of magnitude 60cm, are combined as shown in Figure 2.1. (a) Find the focal length of the lens combination. (b) Calculate the position of the image of the object O placed 30cm from the combination lens. (c) Determine the magnification of the object. (d) Draw a ray diagram to show how the image is formed. [10]O 60 em Figure 2. 13. (a) Explain the meaning of A. Z and the term isotopes of element X in the notation 2X. [3] (b) Given that to = 1.2x 10-15m. estimate the radius of Nitrogen 14/ [2] (c) Given that the atomic mass of Nitrogen is 14.00674u, calculate its binding energy. [5] Data: Mass of proton = 1.00728u Mass of neutron = 1.00867u Mass of electron = 0.00055u lu = 931 Mew