A charged particle having drift velocity of \(7.5\times10^{-4}~\text{ms}^{-1}\) in an electric field of \(3\times10^{-10}~\text{Vm}^{-1}\), has mobility of:
1. \(2.5\times 10^{6}~\text{m}^2\text{V}^{-1}\text{s}^{-1}\)
2. \(2.5\times 10^{-6}~\text{m}^2\text{V}^{-1}\text{s}^{-1}\)
3. \(2.25\times 10^{-15}~\text{m}^2\text{V}^{-1}\text{s}^{-1}\)
4. \(2.25\times 10^{15}~\text{m}^2\text{V}^{-1}\text{s}^{-1}\)
When a \(100\) W, \(240\) V bulb is operated at \(200\) volt, the current in it is:
1. \(0.35~\text{A}\)
2. \(0.42~\text{A}\)
3. \(0.50~\text{A}\)
4. \(0.58~\text{A}\)
For the given circuit, the value of the resistance in which the maximum heat is produced is:
1. \(2~\Omega\)
2. \(6~\Omega\)
3. \(4~\Omega\)
4. \(12~\Omega\)
Twelve wires of equal resistance \(R\) are connected to form a cube. The effective resistance between two diagonal ends \(A\) and \(E\) will be:
1. \(\frac{5 R}{6}\)
2. \(\frac{6 R}{5}\)
3. \(12 R\)
4. \(3 R\)
Three voltmeters are connected as shown.
A potential difference is applied between \(\mathrm{A}\) and \(\mathrm{B}\). On closing the switch \(\mathrm{S}\), readings of voltmeter (s):
1. | \(\mathrm{V_1}\) increases. |
2. | \(\mathrm{V_2}\) increases. |
3. | \(\mathrm{V_2}\) & \(\mathrm{V_3}\) both increases. |
4. | one of \(\mathrm{V_2}\) & \(\mathrm{V_3}\) increases and \(\mathrm{V_1}\) decreases. |
A potential divider is used to give outputs of \(2~\text{V}\) and \(3~\text{V}\) from a \(5~\text{V}\) source, as shown in the figure.
Which combination of resistances, from the ones given below, \(R_1, R_2, ~\text{and}~R_3\) give the correct voltages?1. | \({R}_1=1~\text{k} \Omega, {R}_2=1 ~\text{k} \Omega, {R}_3=2 ~\text{k} \Omega\) |
2. | \({R}_1=2 ~\text{k} \Omega, {R}_2=1~\text{k} \Omega, {R}_3=2~\text{k} \Omega\) |
3. | \({R}_1=1 ~\text{k} \Omega, {R}_2=2~ \text{k} \Omega, {R}_3=2~ \text{k} \Omega\) |
4. | \({R}_1=3~\text{k} \Omega, {R}_2=2~\text{k} \Omega, {R}_3=2~ \text{k} \Omega\) |
A constant voltage is applied between the two ends of a uniform metallic wire. Some heat is developed in it. The heat developed doubles if:
1. | both the length and the radius of the wire are halved. |
2. | both the length and the radius of the wire are doubled. |
3. | the radius of the wire is doubled. |
4. | The length of the wire is doubled. |
A \(50\) kW dc generator produces a potential difference of \(250\) V. If the resistance of the transmission line is \(1~\Omega\), what percentage of the original power is lost during transmission?
1. \(80\%\)
2. \(40\%\)
3. \(20\%\)
4. \(10\%\)
A current of \(2\) A is to be sent through a resistor of \(5 ~\Omega.\) Number of cells required in series, if each has emf \(2\) V and internal resistance \(0.5~\Omega,\) are:
1. \(40\)
2. \(30\)
3. \(20\)
4. \(10\)
Two batteries, one of emf \(18~\text{V}\) and internal resistance \(2~\Omega\) and the other of emf \(12\) V and internal resistance \(1~\Omega\), are connected as shown. Reading of the voltmeter is:
(if voltmeter is ideal)
1. \(14\) V
2. \(15\) V
3. \(18\) V
4. \(30\) V