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 a potentiometer wire = 4m.
Total resistance = `20 Omega`
`:." Resistance per unit length " = 20/4 = 5 Omega`
External resistance ` R = 2980 Omega`
Total Resistance of potentiometer wire `R_p = 20 Omega`
`emf = 4V`
`:." Current I "= E/(R+R_P)`
`= 4/ (2980 + 20 ) = 4 / 3000`
` = 4/3 xx 10^(-3)`
`:." "{:("Potential along"),("the wire"):}} ="V = IR"`
` = 4/3 xx 10^(-3) xx 5`
` = 20/3 xx 10^(-3)`
` = 6.66 xx 10^(-3)`
` = 0.666 xx 10^(-2) V//m`
Potential along the wire ` = 0.666 xx 10^(-2) V m ^(-1)`