Embibe Experts Solutions for Exercise 1: ICSE-2018

Calculate the net emf across $\mathrm{A}$ and $\mathrm{B}$ shown in Figure $\mathit{1}$ below$:$

${\in }_{1}and {\in }_2$ are two batteries having emf of $34 V$ and $10 V$respectively and internal resistance of $1 \Omega and 2 \Omega$ respectively. They are connected as shown in Figure below. Using Kirchhoff's Laws of electrical networks, calculate the currents $I_{1}and I_2$.

$E_1$ and $E_2$ are two batteries having emfs of $3 \mathrm{V}$ and $4 \mathrm{V}$ and internal resistances of $2\mathrm{\Omega }$ and $1 \Omega$ respectively. They are connected as shown in figure below. Using Kirchhoff's laws of electrical circuits, calculate the currents $I_1$ and $I_2$.

In a potentiometer experiment, balancing length is found to be $120 \mathrm{cm}$ for a cell $E_1$ of emf $2 \mathrm{V}$ What will be the balancing length for another cell $E_2$ of emf $1.5 \mathrm{V}$? (No other changes are made in the experiment).

In a potentiometer experiment, the balancing length with a resistance of $2 \mathrm{\Omega }$ is found to be $100 \mathrm{cm}$, while that of an unknown resistance is $500 \mathrm{cm}$. Calculate the value of the unknown resistance.

Obtain the balancing condition for the Wheatstone bridge arrangement as shown in Figure below$:$

Draw a labelled circuit diagram of a potentiometer to measure the internal resistance $\text{'}\mathrm{r}\text{'}$ of a cell. Write the working formula $($derivation is not required$)$.