Calculate: (i) The effective resistance (ii) calculate the potential difference across each resistor (4 marks) (4 marks) (a) 240 V a.c. It is required to run a 6-V, 24-W lamp from 240-V a.c. mains using a transformer as shown above. 40 (i) Calculate the current that would be taken by the lamp when operating normally. (2 marks) Calculate the turns ratio of the transformer you would use. (2 marks) (iii) Calculate the current taken by the primary coil of the transformer, assuming it to be 100% efficient. (2 marks) (iv) Why, in practice, is the efficiency of the transformer less than 100%? (3 marks) (b) State three factors that affect the resistance of a metallic conductor. (3 marks) (c) Four resistors are arranged as shown below 60 10v 6 V 24 W 20 30