A galvanometer, with a scale divided into 150 equal divisions, has current sensitivity of 10 divisions per milliampere and voltage sensitivity of 2 divisions per millivolt. Find shunt resistance for making an ammeter of 6A .

Question

A galvanometer, with a scale divided into 150 equal divisions, has current sensitivity of 10 divisions per milliampere and voltage sensitivity of 2 divisions per millivolt. Find shunt resistance for making an ammeter of 6A . (A) 1.25 × 10- 3 Ω  (B) 12.5 × 10- 3 Ω  (C) 125 × 10- 3 Ω  (D) 0.125 × 10- 3 Ω

Tardigrade Admin · Accepted Answer

. beginarraylIg=15 mathrm~mA Vg=75 mathrmmV I=6 mathrm~A endarray ⇒ Rg=(Vg/Ig)=5 Ω S = (Ig Rg/I - Ig)=12.5 × 10- 3 Ω

Q. A galvanometer, with a scale divided into $150$ equal divisions, has current sensitivity of $10$ divisions per milliampere and voltage sensitivity of $2$ divisions per millivolt. Find shunt resistance for making an ammeter of $6 A$ .

$1.25 \times 1 0^{- 3} Ω$

$12.5 \times 1 0^{- 3} Ω$

$125 \times 1 0^{- 3} Ω$

$0.125 \times 1 0^{- 3} Ω$

$I_{g} = 15 mA V_{g} = 75 mV I = 6 A ⎭ ⎬ ⎫ \Rightarrow R_{g} = \frac{V _{g}}{I _{g}} = 5Ω$
$S = \frac{I _{g} R _{g}}{I - I _{g}} = 12.5 \times 1 0^{- 3} Ω$

Q. A galvanometer, with a scale divided into 150 equal divisions, has current sensitivity of 10 divisions per milliampere and voltage sensitivity of 2 divisions per millivolt. Find shunt resistance for making an ammeter of 6A .

1.25×10−3Ω

12.5×10−3Ω

125×10−3Ω

0.125×10−3Ω