1. Tardigrade
  2. Question
  3. Physics
  4. AB is a potentiometer wire of length 100cm and its resistance is 10 ohm It is connected in series with a resistance R = 40 ohm and a battery of emf 2 volt and negligible internal resistance. If a source of unknown emf E is balanced by 40cm length of the potentiometer wire, the value of E is

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. AB is a potentiometer wire of length 100cm and its resistance is 10 ohm It is connected in series with a resistance $R = 40$ ohm and a battery of emf 2 volt and negligible internal resistance. If a source of unknown emf E is balanced by 40cm length of the potentiometer wire, the value of E is

Current Electricity

Solution:

As we known
$K =\left(\frac{ E }{ R + r }\right) \frac{ r }{ L }$
$K=\left(\frac{2}{10+40}\right) \frac{10}{1}$
$K=\frac{20}{50}$
$\therefore E=K \ell$ [unknown emf]
$E=\frac{20}{50} \times 40 \times 10^{-2}=0.16 volt$