Voltage drop across the terminals of a cell of EMF 2V is 1V when 2 A current is drawn from it. Internal resistance of the cell is?

1.  $2\mathrm{\Omega }$

2.  $1\mathrm{\Omega }$

3.  $0.5\mathrm{\Omega }$

4.  $0.25\mathrm{\Omega }$

When current flows in steady state in the wire whose area of cross-section decreases as shown. Which of the following is incorrect?

1.  Drift speed increases in the direction of current.

2.  Electric field decreases in the direction of current.

3.  Electric Potential decreases in the direction of current.

4.  Current density increases in the direction of current.

‘N’ batteries each of emf E and internal resistance ‘r’ are first connected in series and then in parallel to an external resistance ‘R’. If current through ‘R’ is same in both cases then                      

1.  $\mathrm{R}={\mathrm{r}}^2/\mathrm{N}$

2.  $\mathrm{R}=\mathrm{Nr}/2$

3.  $\mathrm{R}=\mathrm{Nr}$

4.  $\mathrm{R}=\mathrm{r}$

A set of '\(n\)' equal resistors, of value '\(R\)' each, are connected in series to a battery of emf '\(E\)' and internal resistance '\(R\)'. The current drawn is \(I.\) Now, if '\(n\)' resistors are connected in parallel to the same battery, then the current drawn becomes \(10I.\) The value of '\(n\)' is:

A carbon resistor (47 ± 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

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

The potential difference \(V_{A}-V_{B}\) between the points \({A}\) and \({B}\) in the given figure is:
     

The length of a potentiometer wire is l. A cell of emf E is balanced at a length l/3 from the positive end of the wire. If the length of the wire is increased by l/2. At what distance will be the same cell give a balance point.

1.  2l/3

2.  l/2

3.  l/6

4.  4l/3

\({A, B}~\text{and}~{C}\) are voltmeters of resistance \(R,\) \(1.5R\) and \(3R\) respectively as shown in the figure above. When some potential difference is applied between \({X}\) and \({Y},\) the voltmeter readings are \({V}_{A},\) \({V}_{B}\) and \({V}_{C}\) respectively. Then: