Question

Primary coil of a transformer is connected to 220 V ac. Primary and secondary turns of the transforms are 100 and 10 respectively. Secondary coil of transformer is connected to two series resistance shown in shown in figure. The output voltage (V0) is :

• A. 15 V
• B. 7 V
• C. 44 V
• D. 22 V

Answer 1

Answer: (B)

7 V

Answer 2

Calculate the Secondary Voltage Using the Turns Ratio: The turns ratio for a transformer is given by:
$\frac{\epsilon_1}{\epsilon_2} = \frac{N_1}{N_2}$
Substitute $N_1 = 100$, $N_2 = 10$, and $\epsilon_1 = 220 \, V$:
$\epsilon_2 = \frac{N_2}{N_1} \times \epsilon_1 = \frac{10}{100} \times 220 = 22 \, V$
Determine the Equivalent Resistance of the Load: The load consists of two resistances, $15 \, \Omega$ and $7 \, \Omega$, connected in series:
$R_{eq} = 15 + 7 = 22 \, \Omega$
Calculate the Current in the Secondary Circuit: Using Ohm’s law for the secondary circuit:
$I = \frac{\epsilon_2}{R_{eq}} = \frac{22 \, V}{22 \, \Omega} = 1 \, A$
Calculate the Output Voltage Across the 7 $\Omega$ Resistor: The output voltage $V_0$ across the $7 \, \Omega$ resistor is:
$V_0 = I \times 7 = 1 \, A \times 7 \, \Omega = 7 \, V$.