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प्रश्न
Consider a simple circuit shown in figure 
stands for a variable resistance R′. R′ can vary from R0 to infinity. r is internal resistance of the battery (r << R << R0).
- Potential drop across AB is nearly constant as R ′ is varied.
- Current through R′ is nearly a constant as R ′ is varied.
- Current I depends sensitively on R′.
- `I ≥ V/(r + R)` always.
विकल्प
a and b
b and c
c and d
a and d
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उत्तर
a and d
Explanation:
As r << R << R0 < R' from question, R' > R and R' and R are in parallel combination, so the equivalent resistance will be always less than R. So `I ≥ V/(r + R)` and potential across AB will remain nearly constant.
Important point: In parallel combination of resistances, the equivalent resistance is smaller than smallest resistance present in combination.
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