Question

A milliammeter of range `10 mA` and resistance `9 Omega` is joined in a circuit as shown. The metre gives full-scale deflection for curretn `I` when `A` and `B` are used as its terminals, i.e., current enters at `A` and leaves at `B` (`C` is left isolated). The value if `I` is

A. `100 mA`
B. `900 mA`
C. `1 A`
D. `1.1 A`

Answer 1

Correct Answer - C
`i_(g) = 10 mA = 0.01 A`
`V_(A) - V_(B) = (I - i_(g)) 0.1 = i_(g) (9 + 0.9)`
or `I = (10 xx 0.01)/(0.1) = 1A`