Question

A current of 2mA was passed through an unknown resistor which dissipated a power of 4.4 W. Dissipated power when an ideal power supply of 11V is connected across it is :

A. 11×10⁻⁵W
B. 11×10⁻⁴W
C. 11×10⁵W
D. 11×10⁻³W

Answer 1

To find the power dissipated by a resistor at 11V, we calculated the resistance using the initial conditions (4.4W dissipated at 2mA) and applied Ohm's law. The dissipated power when 11V is applied across the 1.1MΩ resistor is 110mW, which corresponds to Option D: 11 x 10⁻³W.

Step-by-step explanation:

The question requires us to find the power dissipated by a resistor when a voltage of 11V is applied across it, given that a current of 2mA results in a power dissipation of 4.4W.

First, we can find the resistance of the resistor using the power dissipated with the original current, which can be represented by the formula P = I²R, where P is the power dissipated, I is the current, and R is the resistance.

With a power dissipation of 4.4W for a current of 2mA (0.002A), we can rearrange the formula and solve for the resistance, R = P/I², which gives us R = 4.4W / (0.002A)² = 1.1MΩ.

Now, using Ohm's law, V = IR, we can determine the power dissipated when 11V is applied by substituting the resistance into the formula P = V²/R, resulting in P = (11V)² / 1.1MΩ, which simplifies to P = 121V² / 1.1MΩ = 0.11W or 110mW.

Therefore, the correct answer is 11 x 10⁻³W (Option D).