Given data

• Primary voltage: $V_p = 230\,\text{V}$
• Frequency: $50\,\text{Hz}$
• Turns ratio: $N_p:N_s = 10:1$
• Load resistance on secondary: $R = 46\,\Omega$

Use transformer relation For an ideal transformer, $\frac{V_p}{V_s} = \frac{N_p}{N_s}$ Hence, $V_s = V_p\cdot \frac{N_s}{N_p} = 230\cdot \frac{1}{10} = 23\,\text{V}$

Power consumed in the load The secondary is connected to a resistor $R = 46\,\Omega$.

Power in a resistor is $P = \frac{V_s^2}{R}$ Substituting, $P = \frac{23^2}{46} = \frac{529}{46} = 11.5\,\text{W}$

Identify correct option $P = 11.5\,\text{W}$ So the correct option is A.

Comparison with stored answer Stored correct answer: A

Our derived answer also gives A. So they agree.