JAMB Physics 2020 Paper

Concept:An ideal transformer changes voltage according to the ratio of turns in the coils.Explanation:The transformer equation is:$$\frac{V_s}{V_p} = \frac{N_s}{N_p}$$Where $V_s$ is the output voltage, $V_p$ is the input voltage, $N_s$ is the secondary turns, and $N_p$ is the primary turns.Given: $N_p = 300$, $N_s = 30$, and $V_p = 100$ V.Substitute the values:$$\frac{V_s}{100} = \frac{30}{300}$$Simplify the turns ratio:$$\frac{30}{300} = \frac{1}{10}$$So:$$V_s = 100 \times \frac{1}{10} = 10 \text{ volts}$$Answer:The output voltage is 10 volts.Correct option: B. 10 volts.