Figure (a) below shows a Wheatstone bridge in which P, Q R, S are fixed resistances, \(G\) is a galvanometer, and \(B\) is a battery. For this particular case, the galvanometer shows zero deflection. Now, only the positions of \(B\) and \(G\) are interchanged. as shown in figure (b). The new deflection of the galvanometer:
1. | is to the left |
2. | is to the right |
3. | is zero |
4. | depends on the values of P, Q, R, S |
An electric heater consists of a nichrome coil and runs under \(220\) V, consuming \(1\) kW of power. Part of its coil burned out and it was reconnected after cutting off the burnt portion. The power it will consume now is:
1. | more than \(1\) kW |
2. | less than \(1\) kW but not zero |
3. | \(1\) kW |
4. | \(0\) |
The circuit shown contains three identical resistors, two ammeters X and Y, and a voltmeter Z. The internal resistance of the battery is negligible.
Which option shows the readings on the three meters?
(Assume the ammeters have negligible resistance, and negligible current flows through the voltmeter.)
1. | X = \(1.0\) A; Y = \(0.0\) A; Z = \(12\) V |
2. | X = \(2.0\) A; Y = \(0.0\) A; Z = \(4.0\) V |
3. | X = \(1.0\) A; Y = \(2.0\) A; Z = \(8.0\) V |
4. | X = \(3.0\) A; Y = \(6.0\) A; Z = \(12\) V |
A student has three \(6.0~\Omega\) resistors that can be connected together in any configuration. What are the maximum and minimum resistance that can be obtained by using one or more of these three resistors?
(Assume the connections between the resistors have negligible resistance, the temperature of the resistors is constant, and the resistors are used in a d.c. circuit and none of the resistors are shortcircuited.)
1. | \(12~\Omega\); minimum resistance: \(0.50~\Omega\) | maximum resistance:
2. | \(6.0~\Omega\); minimum resistance: \(0.50~\Omega\) | maximum resistance:
3. | \(18~\Omega\); minimum resistance: \(6.0~\Omega\) | maximum resistance:
4. | \(18~\Omega\); minimum resistance: \(2.0~\Omega\) | maximum resistance:
Three resistors are connected to a \(20\) V battery with a constant supply. One of the resistors is a variable resistor. The resistance of the variable resistor is gradually increased from zero to \(5\) \(\Omega.\)
Which graph shows how the current from the battery varies with the resistance \((R)\) of the variable resistor?
1. | 2. | ||
3. | 4. |
A battery of internal resistance r, when connected across \(2~\Omega\) resistor supplies a current of 4 A. When the battery is connected across a \(5~\Omega\) resistor, it supplies a current of 2 A. The value of r is:
1. | \(2~\Omega\) | 2 | \(1~\Omega\) |
3. | \(0.5~\Omega\) | 4. | Zero |
In the circuit shown in the figure below, the current supplied by the battery is:
1. 2 A
2. 1 A
3. 0.5 A
4. 0.4 A
The equivalent resistance between points A and B in the circuit shown in the figure is:
1. 6R
2. 4R
3. 2R
4. R
In the circuit shown in the figure below, if the potential difference between B and D is zero, then value of the unknown resistance X is:
1. | 4 Ω | 2. | 2 Ω |
3. | 3 Ω | 4. | EMF of a cell is required to find the value of X |
The figure below shows a network of currents. The current \(i\) will be:
1. \(3~\mathrm{A}\)
2. \(13~\mathrm{A}\)
3. \(23~\mathrm{A}\)
4. \(-3~\mathrm{A}\)