Question

When A $40\mathrm{V}$ battery is connected across an unknown resistor, There is a current Of $100\mathrm{mA}$ In the circuit. Find the value of the resistance of the Resister?

• A. $5000\Omega$
• B. $800\Omega$
• C. $0.8\Omega$
• D. None Of These

Answer 1

The correct option is D

None Of These

Step 1: Given data

$\mathrm{V}=40\mathrm{V}$

$$\begin{gathered} \mathrm{I}=100\mathrm{mA} \\ =0.1\mathrm{A} \end{gathered}$$

Step 2: The formula used

Ohm’s law

1. If all physical conditions and temperatures stay constant, Ohm's law asserts that the voltage across a conductor is directly proportional to the current flowing through it.
2. It can be given as: $\mathrm{V}=\mathrm{IR}$
   Here, $V$ is the voltage, I is current, and $R$ is the resistance.

Step 3: Calculation

By putting the values of V and I in the formula,

$$\begin{gathered} \mathrm{V}=\mathrm{IR} \\ \mathrm{R}=\frac{\mathrm{V}}{\mathrm{I}} \\ =\frac{40}{0.1} \\ =400\mathrm{\Omega } \end{gathered}$$

Thus, the resistance of the register is $400\Omega$.

Therefore, by applying Ohm's Law resistance of the register is $400\Omega$. None of the options satisfy this.