Meter Bridge

A cell can be balanced against 100 cm and 110 cm of potentiometer wire, respectively with and without being short-circuited through a resistance of 10 Ω. Its internal resistance is:

1. 1.0 Ω

2. 0.5 Ω

3. 2.0 Ω

4. zero

A potentiometer circuit is set up as shown in the figure below. The potential gradient across the potentiometer wire is k volt/cm. Ammeter present in the circuit reads 1.0 A when the two-way key is switched off. The balance points, when the key between the terminals (i) 1 and 2 (ii) 1 and 3, is plugged in, are found to be at lengths $l_1$ $cm$ and $l_2$ $cm$ respectively. The magnitudes of the resistors R and X in ohm, are then, respectively, equal to: 

1. $k(l_2-l_1)$ $and$ $k{l}_2$

2. $k{l}_1$ $and$ $k(l_2-l_1)$

3. $k(l_2-l_1)$ $and$ $k{l}_1$

4. $k{l}_1$ $and$ $k{l}_2$

A potentiometer wire of length and a resistance are connected in series with a battery of EMF and resistance . An unknown EMF is balanced at a length l of the potentiometer wire. The EMF will be given by:
1.
2.
3.
4.

A potentiometer is an accurate and versatile device to make electrical measurements of E.M.F. because the method involves:

1.	the potential gradients.
2.	a condition of no current flow through the galvanometer.
3.	a condition of cells, galvanometer, and resistances.
4.	the cells.

A carbon resistor (47 \pm 4.7) kΩ is to be marked with rings of different colours for its identification. The colour code sequence will be:

1. Violet - Yellow - Orange - Silver

2. Yellow - Violet - Orange - Silver

3. Yellow - Green - Violet - Gold

4. Green - Orange - Violet - Gold

Resistance of a carbon resistor determined from colour codes is . The colour of third band must be:
1. Yellow
2. Red
3. Green
4. Orange