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The terminal voltage is (E)/(2) when a c...

The terminal voltage is `(E)/(2)` when a c urrent of 2A is flowing through `2Omega` resistance, then the internal resistance of cell is:-

A

`1Omega`

B

`2Omega`

C

`3Omega`

D

`4Omega`

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The correct Answer is:
To solve the problem step by step, we can follow these instructions: ### Step 1: Understand the Problem We have a circuit with a battery (with EMF \( E \)), a current of \( 2 \, \text{A} \) flowing through a \( 2 \, \Omega \) resistor, and the terminal voltage of the battery is given as \( \frac{E}{2} \). We need to find the internal resistance \( r \) of the battery. ### Step 2: Write Down the Known Values - Current (\( I \)) = \( 2 \, \text{A} \) - Resistance (\( R \)) = \( 2 \, \Omega \) - Terminal Voltage (\( V \)) = \( \frac{E}{2} \) ### Step 3: Apply the Formula for Terminal Voltage The terminal voltage \( V \) can be expressed using the formula: \[ V = E - I \cdot r \] Where: - \( E \) = EMF of the battery - \( r \) = internal resistance of the battery ### Step 4: Substitute Known Values into the Formula Since we know that \( V = \frac{E}{2} \), we can substitute this into the equation: \[ \frac{E}{2} = E - I \cdot r \] Substituting \( I = 2 \, \text{A} \): \[ \frac{E}{2} = E - 2r \] ### Step 5: Rearrange the Equation Now, let's rearrange the equation to isolate \( r \): \[ 2r = E - \frac{E}{2} \] This simplifies to: \[ 2r = \frac{E}{2} \] ### Step 6: Solve for Internal Resistance \( r \) Now, divide both sides by 2: \[ r = \frac{E}{4} \] ### Step 7: Find the Value of \( E \) To find \( E \), we can use the voltage drop across the \( 2 \, \Omega \) resistor: \[ V = I \cdot R = 2 \, \text{A} \cdot 2 \, \Omega = 4 \, \text{V} \] Since \( V = \frac{E}{2} \): \[ \frac{E}{2} = 4 \, \text{V} \] Thus: \[ E = 8 \, \text{V} \] ### Step 8: Substitute \( E \) Back to Find \( r \) Now substitute \( E = 8 \, \text{V} \) back into the equation for \( r \): \[ r = \frac{8 \, \text{V}}{4} = 2 \, \Omega \] ### Conclusion The internal resistance of the cell is \( r = 2 \, \Omega \). ---
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