Question

An electric bulb is designed to draw power P₀ at voltage V₀. If the voltage is V it draws a power P. Then

• A. $P = \left( \frac{V_{0}}{V} \right)^{2}P_{0}$
• B. $P = \left( \frac{V}{V_{0}} \right)^{2}P_{0}$
• C. $P = \left( \frac{V}{V_{0}} \right)P_{0}$
• D. $P = \left( \frac{V_{0}}{V} \right)P_{0}$

Answer 1

Answer: (B)

$P = \left( \frac{V}{V_{0}} \right)^{2}P_{0}$

Answer 2

$P \propto V^{2}$⇒ $\frac{P}{P_{0}} = \left( \frac{V}{V_{0}} \right)^{2} \Rightarrow P = \left( \frac{V}{V_{0}} \right)^{2}P_{0}$