A step up transformer is used on 120 V line to provide a P.D. of 2400 V. If the number of turns in primary is 75, then the number of turns in the secondary shall be

1500

Here E_P = 120 V, E_S = 2400 V, N_p = 75 and N_s = ?

            $\frac{E_s}{E_p} = \frac{N_s}{N_p} $

$ N_s = \frac{E_s}{E_p} \times N_p = \frac{2400}{120} \times 75 = 1500$