The resistance of a 100 W, 200 V lamp is

Question

Examoogle · Accepted Answer

400 ohm

Explanation: Given: Power of the lamp P = 100 W, Voltage rating V = 200 V Formula Used: $$R = \frac{V^2}{P}$$ Steps: Identify the relevant formula: The relationship between power $P$, voltage $V$, and resistance $R$ for an electrical appliance is given by the formula $P = \frac{V^2}{R}$. We need to calculate $R$.. Substitute the given values: Substitute the given values into the rearranged formula: $V = 200$ V and $P = 100$ W.. Calculate the final resistance: Perform the arithmetic: $200^2 = 40,000$. Then, $40,000 / 100 = 400$. Answer: C is correct because using the relation $R = V^2 / P$, we find $R = (200)^2 / 100 = 400 \ \Omega$. Exam Tip: In AC circuits, this calculated resistance is often called the 'hot resistance' of the lamp, which is significantly higher than the resistance measured at room temperature due to the temperature coefficient of the tungsten filament.

Related Questions

Discussion (0)