A cell having an emf \(\varepsilon\) and internal resistance \(r\) is connected across a variable external resistance \(R\). As the resistance \(R\) is increased, the plot of potential difference \(V\) across \(R\) is given by:

1.		2.
3.		4.

In the circuit shown in the figure below, if the potential at point \(A\) is taken to be zero, the potential at point \(B\) will be:

1. \(+1\) V
2. \(-1\) V
3. \(+2\) V
4. \(-2\) V

A thermocouple of negligible resistance produces an e.m.f. of 40 µV/ºC in the linear range of temperature. A galvanometer of resistance 10 ohm whose sensitivity is 1 µA/division, is employed with the thermocouple. The smallest value of temperature difference that can be detected by the system will be:
1. 0.25ºC
2. 0.5 ºC
3. 1ºC
4. 0.1ºC

The power dissipated in the circuit shown in the figure is \(30~\text{Watts}\). The value of \(R\) is:
    
1. \(15~\Omega\)
2. \(10~\Omega\)
3. \(30~\Omega\)
4. \(20~\Omega\)

The net resistance of the circuit between \(A\) and \(B\) is:

Two batteries, one of emf \(18\) volts and internal resistance \(2~\Omega\) and the other of emf \(12\) V and internal resistance \(1~\Omega,\) are connected as shown. The voltmeter \(\mathrm{V}\) will record a reading of: 

1. \(18\) V
2. \(30\) V
3. \(14\) V
4. \(15\) V

A \(5~\text A\) fuse wire can withstand a maximum power of \(1~\text W\) in a circuit. The resistance of the fuse wire is:
1. \(5~\Omega\)
2. \(0.04~\Omega\)
3. \(0.2~\Omega\)
4. \(0.4~\Omega\)

When a wire of uniform cross-section a, length l, and resistance R is bent into a complete circle, the resistance between any two diametrically opposite points will be:

1. R/2

2. R/4

3. R/8

4. 4R

For the network shown in the figure below, the value of the current \(i\) is:

     
1. \(\frac{18V}{5}\)
2. \(\frac{5V}{9}\)
3. \(\frac{9V}{35}\)
4. \(\frac{5V}{18}\)

A car battery of emf \(12~\text{V}\) and internal resistance \(5\times 10^{-2}~\Omega\) receives a current of \(60~\text{A}\) from an external source. The terminal voltage of the battery is: