The rest positions of the needles in a milliammeter and voltmeter when not being used in a circuit are shown in the figure. The 'zero error' and 'least count' of these two instruments are

The only correct statement for the two circuits X and Y shown below:

The only correct statement for the following circuit is:

Three students (A), (B) and (C) connect their two given resistor $R_1$ and $R_2$ in the manner shown below:

They connect the terminals marked X and Y above to the two terminals marked X and Y in the circuit given below:

They record the ammeter readings $\left(I\right)$ for different positions of the rheostat and the corresponding voltmeter readings $\left(V\right)$. The average value of the ratio $\raisebox{1ex}{$V$}\!\left/ \!\raisebox{-1ex}{$I$}\right.$ in their observations would be minimum for:

To study the dependence of current $\left(I\right)$ on the potential difference $\left(V\right)$ across a resistor, two students used the two set-ups shown in figure (A) and (B) respectively. They kept the contact $J$ in different positions marked $\left(1\right)$, $\left(2\right)$, $\left(3\right)$, $\left(4\right)$, in the two figures.

For the two students, their ammeter and voltmeter readings will be minimum when the contact $J$ is in the position:

While performing the experiment to study the dependence of current on potential difference across a resistor, the following observations were made by four students, A, B, C and D.

The student who made the wrong observation is:

A $6 \mathrm{V}$ battery (of internal resistance $20 \mathrm{\Omega }$) is connected across a $10 \mathrm{\Omega }$ resistor and a switch in series, as shown:

If the switch is kept in the off position, as shown in the figure, then:

A student set up his circuit for finding the equivalent resistance of a series combination of two given resistors $R_1$ and $R_2$ in the manner as shown below. He did not obtain the correct result in his experiment because of a mistake in the circuit. This mistake can be corrected by shifting the component: