A microameter has a resistance of `100 omega` and a full scale range of ` 50 muA`. It can be used as a voltmeter or as a higher range ammeter provides a resistance is added to it . Pick the correct range and resistance combination(s)

Options

A. `50V` range with `10kOmega` resistance in series
B. `10V` range with `200kOmega` resistance in series
C. `5mA` range with `1Omega` resistance in parallel
D. `10mA` range with `1Omega` resistance in parallel

Answer

B, C

Explanation

Here, `G=100Omega`, `I_g=50xx10^-6A=5xx10^-5A`
For a voltmeter of range `50V`,
`R=(50)/(5xx10^-5)-100=10^6-10^2=9*999xx10^5Omega`
For a voltmeter of range `10V`,
`R=(10)/(5xx10^-5)-100=199,900Omega`
`~~200kOmega` in series
For an ammeter of range `5mA`,
`S=(5xx10^-5xx100)/(5xx10^-3-5xx10^-5)~~1Omega` in parallel
For an ammeter of range `10mA`
`S=(5xx10^-5xx100)/(10xx10^-3-5xx10^-5)=0*5Omega` in parallel