A : When two cells of equal EMF and equal internal resistances are connected is parallel with positive plate of the other than , the net EMF , of the combination will be equal to the EMF of each cell.
R : Effective internal resistance of the parallel combination of two identical cells will be half of the internal resistance of each cell.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion , then mark
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion then mark.
C. If Assertion is ture statement but Reason is false , then mark
D. If both Assertion and Reason are false statements then mark.

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided in the statement.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that when two cells of equal EMF (E) and equal internal resistances (R) are connected in parallel, the net EMF of the combination will be equal to the EMF of each cell.
- We know that when identical cells are connected in parallel, the EMF remains the same as that of each individual cell. Therefore, the assertion is correct.

2. **Understanding the Reason (R)**:
- The reason states that the effective internal resistance of the parallel combination of two identical cells will be half of the internal resistance of each cell.
- When two resistances (in this case, internal resistances of the cells) are connected in parallel, the formula for effective resistance \( R_{eq} \) is given by:
\[ \frac{1}{R_{eq}} = \frac{1}{R} + \frac{1}{R} \]
- Simplifying this gives:
\[ \frac{1}{R_{eq}} = \frac{2}{R} \implies R_{eq} = \frac{R}{2} \]
- This shows that the effective internal resistance of the combination is indeed half of the internal resistance of each cell. Therefore, the reason is also correct.

3. **Conclusion**:
- Both the assertion (A) and the reason (R) are correct. However, the reason does not explain the assertion adequately. Hence, the correct answer to the question is that both statements are true, but the reason is not a valid explanation for the assertion.

### Final Answer:
- Both A and R are correct, but R does not explain A.