Question

A step up transformer raises the voltage from 220V to 11000V. If the number of turns of the secondary be 1000, the number of turns of the primary is

• A. 2
• B. 20
• C. 200
• D. 2000

Answer 1

Answer: (B)

20

Answer 2

$\frac{E_p}{E_s} = \frac{N_p}{N_s} \, \Rightarrow \, N_p = \frac{E_p}{E_s} \times N_s = \frac{220}{11000 } \times 1000 = 20$