Question

If two resistors of resistances R₁ = (4 ± 0.5) Ω and R₂ = (16 ± 0.5) Ω are connected in series. The eqivalent resistance with the limits of percentage error is ______.

Options

• (20 ± 1%) Ω

• (20 ± 5%) Ω

• (20 ± 0.25 %) Ω

• (20 ± 0.5 %) Ω

Answer 1

If two resistors of resistances R₁ = (4 ± 0.5) Ω and R₂ = (16 ± 0.5) Ω are connected in series. The eqivalent resistance with the limits of percentage error is (20 ± 1%) Ω.

Explanation:

In series combination, equivalent resistance Req = R₁ + R₂

Given, R₁ = (r₁ + Δr₁) = (4 ± 0.5) Ω

R₂(r + Δr₂) = (16 ±  0.5) Ω 

∴ Req = (r₁ + r₂) ± (Δr₁ + Δr₂)

= (4 + 16) ± (0.5 + 0.5) = Ω

∴ Req = (20 ± 1%) = Ω