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. \(2.25\times 10^{15}~\text{m}^2\text{V}^{-1}\text{s}^{-1}\)

Subtopic:  Current & Current Density |
 83%
Level 1: 80%+
NEET - 2020
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When a \(100~\text{W},\) \(240~\text{V}\) bulb is operated at \(200~\text{volt},\) the current in it is:
1. \(0.35~\text{A}\)
2. \(0.42~\text{A}\)
3. \(0.50~\text{A}\)
4. \(0.58~\text{A}\)

Subtopic:  Heating Effects of Current |
 64%
Level 2: 60%+
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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. \(12~\Omega\)

Subtopic:  Heating Effects of Current |
 67%
Level 2: 60%+
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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. \(\dfrac{5 R}{6}\) 2. \(\dfrac{6 R}{5}\)
3. \(12 R\) 4. \(3 R\)
Subtopic:  Kirchoff's Voltage Law |
 70%
Level 2: 60%+
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Three voltmeters are connected as shown.

       

A potential difference is applied between \(A\) and \(B\). On closing the switch \(S\), readings of voltmeter(s):
1. \({V_1}\) increases.
2. \({V_2}\) increases.
3. \({V_2}\) & \({V_3}\) both increases.
4. one of \(V_2\) & \({V_3}\) increases and \({V_1}\) decreases.
Subtopic:  Combination of Resistors |
 54%
Level 3: 35%-60%
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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. \({R}_1=3~\text{k} \Omega, {R}_2=2~\text{k} \Omega, {R}_3=2~ \text{k} \Omega\)
Subtopic:  Combination of Resistors |
 81%
Level 1: 80%+
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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.

Subtopic:  Heating Effects of Current |
 56%
Level 3: 35%-60%
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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. \(10\%\)

Subtopic:  Heating Effects of Current |
Level 3: 35%-60%
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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. \(10\)

Subtopic:  Grouping of Cells |
 78%
Level 2: 60%+
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Two batteries, one of emf \(18~\text{V}\) and internal resistance \(2~\Omega\) and the other of emf \(12~\text V\) and internal resistance \(1~\Omega,\) are connected as shown. Reading of the voltmeter is:
(if a voltmeter is ideal)

            

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

Subtopic:  Grouping of Cells |
 77%
Level 2: 60%+
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