A transformer is connected to a 250 V a.c. supply. The primary coil has 5000 turns and the secondary voltage is found to be 10 V. What is the number of turns in the secondary coil?
A
100
B
150
C
200
D
250
E
300
Verified Correct Answer: C.
Physical Principles & Numerical Solution
To find the number of turns in the secondary coil of a transformer, we use the transformer equation:
\(\frac{V_p}{V_s} = \frac{N_p}{N_s}\)
Given:
\( V_p = 250 \, \text{V}\)
\( V_s = 10 \, \text{V} \)
\( N_p = 5000 \, \text{turns} \)
Rearranging the equation to find \( N_s \):
\(N_s = N_p \times \frac{V_s}{V_p}\)
Plugging in the values:
\(N_s = 5000 \times \frac{10}{250}\)
\(N_s = 5000 \times 0.04\)
\(N_s = 200 \, \text{turns}\)
Therefore, the number of turns in the secondary coil is 200.
Source: Myschool Past Questions Archive (Record #42845)