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A wire is connected to form an equilateral triangle \(ABC\), each side having a resistance of \(4~\Omega\). The vertex \(C\) is maintained at zero volts (\(V_C=0\)), and currents flowing in at \(A\) and \(B\) are as shown in the figure. The ratio of the potentials at \(D\) and \(E\) \(\Big(i.e.~\frac{V_D}{V_E}\Big)\) equals:
1. \(\dfrac31\) 2. \(\dfrac21\)
3. \(\dfrac11\) 4. \(\dfrac53\)

Subtopic:  Kirchoff's Current Law |
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\(AB\) is a \(20~\Omega\) resistor with a tapping point \(C\) that can be moved along \(AB\). The resistances in \(AC,BC\) are proportional to the lengths \(AC,BC\). Initially, \(C\) is at the mid-point of \(AB\) and the circuit is switched on.
                           
If the tapping point \(C\) is moved so that the length \(BC\) is reduced to half its initial value, then the voltage across the \(15~\Omega\) resistor,
1. increases by \(1\) V
2. decreases by \(1\) V
3. increases by \(3\) V
4. decreases by \(3\) V
Subtopic:  Kirchoff's Voltage Law |
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Find the current through the rightmost \(2~\Omega\) resistor.
        
1. \(1~\text{A}\)
2. \(2~\text{A}\)
3. \(0.5 ~\text{A}\)
4. \(0.25~\text{A}\)
Subtopic:  Kirchoff's Voltage Law |
 57%
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The potential difference between the ends of a \(12~\text{V}\) battery when it is being charged by a \(2~\text{A}\) charger is found to be \(13.2~\text{V}\). If this battery is connected in a circuit with a \(6~\Omega\) resistance, the current will be nearly:
1. \(2~\text{A}\) 2. \(1~\text{A}\)
3. \(1.8~\text{A}\) 4. \(2.2~\text{A}\)
Subtopic:  Kirchoff's Voltage Law |
 52%
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In a Wheatstone Bridge arrangement, as shown in the figure, the bridge is balanced. However, when the resistances in the arms \(P,Q\) are switched, the bridge is balanced only when \(R\) is replaced by \(4R\) in the other two arms. If the value of \(R\) is \(100\) \(\Omega\), that of \(S\) is:
1. \(100~\Omega\) 2. \(50~\Omega\)
3. \(200~\Omega\) 4. \(400~\Omega\)
Subtopic:  Wheatstone Bridge |
 56%
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Given below are two statements:
Several resistances \(R_1, R_2, .........R_n\) are connected in parallel. The equivalent resistance of the combination is \(R\).
Assertion (A): The fractional error in \(R\) is most affected by that of the smallest resistance in the combination, other things being equal.
Reason (R): In parallel, the conductances add. The contribution to the overall error in the conductance is largest for the largest conductance or the smallest resistance.
 
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. (A) is False but (R) is True.
Subtopic:  Combination of Resistors |
 59%
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Two non-ideal batteries are connected in parallel: Battery of EMF \(E_1,\) resistance \(r_1\) and of EMF \(E_2\), resistance \(r_2.\) The resulting equivalent battery has EMF '\(E,\)' resistance \(r.\) If \(r_1<r_2,\) 
1. \(|E-E_1|<|E-E_2|\)
2. \(|E+E_1|<|E+E_2|\)
3. \(|E-E_1|>|E-E_2|\)
4. \(|E+E_1|>|E+E_2|\)
Subtopic:  Grouping of Cells |
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A uniformly increasing current flows through a \(30\) \(\Omega\) resistance, as shown in the graph.
             
The thermal energy generated in the resistance due to Joule heating is:
1. \(240\) J
2. \(480\) J
3. \(160\) J
4. \(320\) J
Subtopic:  Heating Effects of Current |
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All the resistances to the left of the vertical line \(PQ\) are \(1~\Omega\), while those on the right of line \(PQ\) are \(2~\Omega\) as shown in the figure above. The equivalent resistance between \(A\) and \(B\) is:

1. \(18~\Omega\) 2. \(9~\Omega\)
3. \(4.5~\Omega\) 4. \(2.25~\Omega\)
Subtopic:  Combination of Resistors |
 71%
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Given below are two statements: 
Assertion (A): In the Wheatstone Bridge shown in the figure, if the resistances in opposite arms are switched (i.e. \(Q, R\) are exchanged) then the bridge remains balanced if it was initially balanced. 
Reason (R): The balance condition \(\dfrac P Q\) = \(\dfrac R S\) is not affected if resistances in opposite arms are switched. 
1. (A) is True but (R) is False.
2. (A) is False but (R) is True.
3. Both (A) and (R) are True and (R) is a correct explanation of  (A).
4. Both (A) and (R) are True but (R) is not a correct explanation of (A).
Subtopic:  Wheatstone Bridge |
 82%
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