Two resistors R₁ and R₂ in PARALLEL have equivalent resistance:
AR₁ + R₂ sum directly
BR₁ R₂ / (R₁ + R₂)
C(R₁ + R₂) / 2 mean
DR₁ − R₂ difference
Answer & Solution
Correct answer: B. R₁ R₂ / (R₁ + R₂)
1. Same V across both; currents add.
2. 1/R_eq = 1/R₁ + 1/R₂ ⇒ R_eq = R₁ R₂ / (R₁ + R₂).
3. R_eq is always LESS than the smallest resistor in the parallel combination.
_Source: NCERT Class 12 Physics Ch 3 §3.10 Series and Parallel_
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