Two resistances of $400 \mathrm{\Omega }$ and $800 \mathrm{\Omega }$ are connected in series with $6 \mathrm{V}$ battery of negligible internal resistance. A voltmeter of resistance $10000 \mathrm{\Omega }$ is used to measure the potential difference across $400 \mathrm{\Omega }$. The error in the measurement of the potential difference, in $\mathrm{volts}$, is approximately

A galvanometer, having a resistance of $50 \mathrm{\Omega }$, gives a full-scale deflection for a current of $0.05 \mathrm{A}$. The length, in $\mathrm{metre}$, of a resistance wire of area of cross-section $2.97\times {10}^{-2} {\mathrm{cm}}^2$, that can be used to convert the galvanometer into an ammeter, which can read a maximum of $5 \mathrm{A}$ current, is

(Specific resistance of the wire $=5\times {10}^{-7} \mathrm{\Omega } \mathrm{m}$)

What is the reading of the voltmeter in the following figure?

In the circuit shown in the figure, reading of voltmeter is $V_1$ when only $S_1$ is closed, reading of voltmeter is $V_2$ when only $S_2$ is closed and reading of voltmeter is $V_3$ when both $S_1$ and $S_2$ are closed. Then,

The graph which represents the relation between the total resistance $R$ of a multi-range moving coil voltmeter and its full-scale deflection $V$ is
   

The ammeter has range of $1$ $\mathrm{A}$, without shunt. The range can be varied by using different shunt resistances. The graph between shunt resistance and range will have the nature as

In the circuit shown here, the readings of the ammeter and voltmeter are