Question

A galvanometer having 30 divisions has a current sensitivity of 20 μA/division. It has a resistance of25 Ω. The value of resistance that should be connected to convert it into an ammeter of range 1 amp is –

• A. 0.15 Ω in series
• B. 0.15 Ω in parallel
• C. 0.015 Ω in series
• D. 0.015 Ω in parallel

Answer 1

Answer: (D)

0.015 Ω in parallel

Answer 2

S = $\frac{I_{g}R_{g}}{I_{A} - I_{g}}$ = $\frac{600\mu A \times 25}{1 - 600\mu A}$

=15000 × 10^–6 = 0.015 Ω