Question

(i) Draw a labelled diagram of a step-up transformer and describe its working principle. Explain any three causes for energy losses in a real transformer. (ii) A step-up transformer converts a low voltage into high voltage. Does it violate the principle of conservation of energy ? Explain. (iii) A step-up transformer has 200 and 3000 turns in its primary and secondary coils respectively. The input voltage given to the primary coil is 90 V. Calculate : (1) The output voltage across the secondary coil (2) The current in the primary coil if the current in the secondary coil is 2·0 A.

The primary coil of an ideal transformer is supplied with an alternating voltage Vₚ. Obtain an expression for the voltage Vₛ induced in its secondary coil having Nₛ turns. Mention two main sources of power loss in real transformers.