Physics Past Questions and Answers

Which of the following actions will not lead to an increase in the induced e.m.f. in a coil of wire rotating between the poles of a magnet? Increasing the

A transformer has 400 turns and 200 turns in the primary and secondary windings respectively. If the current in the primary and secondary windings are 3A and 5A respectively. calculate the efficiency of the transformer?

A freely-suspended magnet swinging in a horizontal plane comes to rest with its axis pointing approximately

Calculate the inductance L, of the coil in the circuit diagram shown above

In a model of the hydrogen atom, the energy levels W_n are given by the formula W_n = -\(\frac{R}{n^2}\), where n is an integer and R is a constant. Determine the energy released in the transition from n = 3 to n = 2.