Exercise - 2

A meter bridge is set-up as shown to determine an unknown resistance $X$ using a standard $10 \mathrm{\Omega }$ resistor. The galvanometer shows null point when tapping-key is at $52 \mathrm{cm}$ mark. The end-corrections are $1 \mathrm{cm}$ and $2 \mathrm{cm}$, respectively for the ends $A$ and $B$. The determined value of $X$ is

If $400 \mathrm{\Omega }$ of resistance is made by adding four $100 \mathrm{\Omega }$ resistance of tolerance $5\%$ then the tolerance of the combination is 

What is the final potential $(\mathrm{in} \mathrm{V})$ of point $b$ with respect to ground in steady state after switch $S$ is closed ? How much charge flows through switch $S$ from $b \mathrm{to} a$ after it is closed in $\mathrm{\mu C}$?

By mistake, a voltmeter is placed in series and an ammeter in parallel with resistance in an electric circuit, with a cell in series. 

A micro-ammeter has a resistance of $100 \mathrm{\Omega }$ and full scale range of $50 \mathrm{\mu A}$. It can be used as a voltmeter and an ammeter of a higher range provided a resistance is added to it. Pick the correct range and resistance combination (s).

Two cells of unequal emfs ${\epsilon }_1$ and ${\epsilon }_2$ and internal resistances $r_1$ and $r_2$are joined as shown. $V_A$ and $V_B$ are the potentials at $A$ and $B$, respectively. 

In the potentiometer arrangement shown, the driving cell $D$ has emf $\epsilon$ and internal resistance $r$. The cell $C$, whose emf is to be measured, has emf $\frac{\epsilon }{2}$ and internal resistance $2r$. The potentiometer wire is the potentiometer wire is $100-\mathrm{cm}$ long. If balance is obtained at the length $AJ=l.$

Choose the correct alternatives.