The resistance of an ammeter having a range of 0 to 5 A is `1.8 Omega`. It is shunted by a small resistance of `0.2 Omega`. If the original dial and the scale indicating the current is not changed, then the effective current when its pointer indictaes 1.5 A will be

Options

A. `10 A`
B. `15 A`
C. `20A`
D. `5 A`

Answer

B

Explanation

When in shunted `I_g=(S/(S+G))I=(0.2/(0.2 +1.8))xx 5 =1/2 A therefore n=I/I_g=5/(1/2)=10 therefore`The range increases by 10 times. `therefore` When the pointer indicates 1.5 A, the actual circuit current is 15A.