The emf of a storage battery of a car is 6.0 V. If internal resistance of the battery is 0.2 $\Omega$, then maximum power drawn from the battery is ____ W.
Show Hint
Maximum \textbf{Efficiency} occurs when $R$ is very large, but Maximum \textbf{Power} occurs specifically when $R = r$.
Step 1: Understanding the Concept:
According to the Maximum Power Transfer Theorem, maximum power is delivered to an external load when the load resistance $R$ is equal to the internal resistance $r$ of the source ($R = r$). Step 2: Formula Application:
Maximum Power $P_{max} = \frac{E^2}{4r}$. Step 3: Explanation:
Given $E = 6.0$ V and $r = 0.2$ $\Omega$.
$$P_{max} = \frac{(6.0)^2}{4 \times 0.2} = \frac{36}{0.8} = 45 \text{ W}$$ Step 4: Final Answer:
The maximum power is 45 W.