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Two cells of same emf but different inte...

Two cells of same emf but different internal resistance are connected in parallel so as to send current in same direction.
STATEMENT-1 `:` The equivalent emf of the combination is equal to individual emf of each cell.
and
STATEMENT-2 `:` The equivalent emf is the arithmetic mean of the individual emfs.

A

Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement-1

B

Statement-1 is True, Statement-2 is True, Statement-2 is NOT a correct explanation for Statement-1

C

Statement-1 is True, Statement-2 is True

D

Statement-1 is False , Statement-2 is True

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the statements regarding the equivalent EMF of two cells connected in parallel with different internal resistances. ### Step-by-Step Solution: 1. **Understanding the Configuration**: - We have two cells, each with the same EMF (let's call it E) but different internal resistances (let's denote them as R1 and R2). - These cells are connected in parallel in such a way that they send current in the same direction. 2. **Applying Kirchhoff's Law**: - When connected in parallel, the voltage across both cells must be the same. Let this common voltage be V. - For cell 1: The current I1 flowing through it can be expressed as: \[ I_1 = \frac{V - E}{R_1} \] - For cell 2: The current I2 flowing through it can be expressed as: \[ I_2 = \frac{V - E}{R_2} \] 3. **Total Current in the Circuit**: - The total current I flowing from the combination of the two cells is the sum of the individual currents: \[ I = I_1 + I_2 = \frac{V - E}{R_1} + \frac{V - E}{R_2} \] 4. **Rearranging the Equation**: - We can factor out (V - E): \[ I = (V - E) \left( \frac{1}{R_1} + \frac{1}{R_2} \right) \] 5. **Finding the Equivalent EMF**: - We can express the equivalent EMF (E_eq) in terms of the currents and resistances: \[ E_{eq} = \frac{E}{R_1} + \frac{E}{R_2} \div \left( \frac{1}{R_1} + \frac{1}{R_2} \right) \] - This shows that the equivalent EMF is not simply equal to the individual EMF E. 6. **Evaluating the Statements**: - **Statement 1**: "The equivalent EMF of the combination is equal to individual EMF of each cell." - This statement is **True** because the voltage across the parallel combination remains equal to the EMF of the cells. - **Statement 2**: "The equivalent EMF is the arithmetic mean of the individual EMFs." - This statement is **False** because the equivalent EMF is not the arithmetic mean but rather a weighted average based on the internal resistances. ### Conclusion: - **Final Answer**: Statement 1 is true, and Statement 2 is false.
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Knowledge Check

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    A
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    B
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    C
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    D
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