A potentiometer wiere has a length of 4 and resistance of `20 Omega`. It is connected in series with resistance of `2980 Omega ` and a cell of emf 4 V. Calcaulte the potential along the wire.

Explanation

Length of the potential wire, `l=4m`
Resistance of the wire, `r=20Omega`
Resistance connected series with potentiometer wire, `R=2980Omega`
Emf of the cell, `xi=4V`
Effective resistance, `R_(s)=r+R=20+2980=3000Omega`
Current flowing through the wire, `I=(xi)/(R_(s))=(4)/(3000)`
`I=1.33xx10^(-3)A`
Potential drop across the wire, `V=Ir`
`=1.33xx10^(-3)xx20`
`V=26.6xx10^(-3)V`
Potential gradient `=("Potential drop across the wire")/("length of the wire")=(V)/(l)=(26.6xx10^(-3))/(4)`
`=6.65xx10^(-3)`
Potential gradient `=0.66xx10^(-2)Vm^(-1)`