A pointer galvanometer with a scale of 30 divisions has a resistance of `12 Omega ` full scale deflection is obtained for a current of 3mA .Calculate the current sensitivity of the galvanometer .How will you convert this galvanometer into a voltage of range 0 to 18 V ?

Explanation

given `: theta = 30 ,G = 12 Omega ,I =3 mA ,V=18 V,S_1 =? ,R=?`
current sensitivity `S_1 =theta/1 = (30 )/(3 xx 10^(-3))`
` S_I = 10 xx 10^3 `
`S_I =10^4 d I v //A `
`R=(V)/(I_g) -G `
`= ( 18)/( 3 xx 10^(-3) ) -12`
`R=600-12 = 5988 Omega `
By connecting `R=5988 Omega ` in series with the galvanometer .