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
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 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. |
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:
1. | \(\frac{8}{3}~\Omega\) | 2. | \(\frac{14}{3}~\Omega\) |
3. | \(\frac{16}{3}~\Omega\) | 4. | \(\frac{22}{3}~\Omega\) |
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 \(5\text-\)ampere fuse wire can withstand a maximum power of \(1\) watt 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:
1. | \(12~\text{V}\) | 2. | \(9~\text{V}\) |
3. | \(15~\text{V}\) | 4. | \(20~\text{V}\) |