An electric motor rated 1100 W is connected to 220 V mains. Find: (i) The current drawn from the mains, (ii) Electric energy consumed if the motor is…

\[\begin{aligned} \text { Current drawn } & =I=\frac{P}{V} \\ & =\frac{1100 \mathrm{~W}}{220 \mathrm{~V}}=5 \mathrm{~A} \end{aligned} \]

\[E=P \times t \]

\[=1100 \mathrm{~W} \times 5 \mathrm{~h} \times 6=33000 \mathrm{~Wh} \]

Cost of one commercial unit $\displaystyle =₹ 5$

Energy consumed $\displaystyle =33 \mathrm{kWh}=33$ unit $\displaystyle =118.8 \times 10^{6} \mathrm{~J}$

Cost of $\displaystyle 33$ unit $\displaystyle =33 \times 5=₹ 165$

Effective resistance of the circuit

\[\begin{array}{l} R_{s}=R_{3}+R_{4}=4 \Omega+6 \Omega=10 \Omega \\ \frac{1}{R_{p}}=\frac{1}{R_{s}}+\frac{1}{R_{2}}=\frac{1}{10 \Omega}+\frac{1}{10 \Omega}=\frac{2}{10 \Omega}=\frac{1}{5 \Omega} \\ R_{p}=5 \Omega \end{array} \]

Total resistance of the circuit $\displaystyle =R_{1}+R_{p}+R_{5}=5+5+10=20 \Omega$

Current drawn from the battery

\[\begin{array}{l} V=20 \mathrm{~V}, R=20 \Omega \\ I=\frac{V}{R}=\frac{20 \mathrm{~V}}{20 \Omega} \\ I=1 \mathrm{~A} \end{array} \]

Reading in voltmeter connected across $\displaystyle 5 \Omega$ Resistance

\[\begin{array}{l} V=I R \\ \mathrm{I}=1 \mathrm{~A} \\ \mathrm{R}=5 \Omega \\ \mathrm{~V}=1 \mathrm{~A} \times 5 \Omega=5 \mathrm{~V} \end{array} \]

SECTION-C