Current Electricity

The Wheatstone bridge shown in figure, here, gets balanced when the carbon resistor used as R1 has the colour code (Orange, Red, Brown). The resistors R2 and R4 are 80\(\Omega\) and 40\(\Omega\), respectively. Assuming that the colour cod...

A current of 2 mA was passed through an unknown resistor which dissipated a power of 4.4 W. Dissipated power when an ideal power supply of 11 V is connected across it is -

The actual value of resistance R, shown in the figure is 30\(\Omega\). This is measuered in an experiment as shown
using the standard formula R = \({V \over {\rm I}}\), where V and I are the readings of the voltmeter and ammeter, respectiv...

A current of 5 A passes through a copper
conductor (resistivity = 1.7 × 10–8 \(\Omega\)m) of radius
of cross-section 5 mm. Find the mobility of the
charges if their drift velocity is 1.1 × 10–3 m/s.

In a meter bridge experiment, the circuit
diagram and the corresponding observation
table are shown in figure


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In the given circuit, an ideal voltmeter
connected across the 10\(\Omega\) resistance reads 2V.
The internal resistance r, of each cell is:

In an experiment, the resistance of a material
is plotted as a function of temperature (in some
range). As shown in the figure, it is a straight
line. One may conclude that :

A moving coil galvanometer allows a full scale
current of 10–4 A. A series resistance of 2 M\(\Omega\)
is required to convert the above galvanometer
into a voltmeter of range 0-5 V. Therefore the
value of shunt resistance required to conve...

Space between two concentric conducting spheres of radii a and b (b > a) is filled with a medium of
resistivity \(\rho\). The resistance between the two spheres will be :

A galvanometer with its coil resistance 25 \(\Omega\) requires a current of 1 mA for its full deflection. In order to construct an ammeter to read upto a current of 2 A, the approximate value of the shunt resistance should be :

A heating element has a resistance of 100 \(\Omega\) at room temperature. When it is connected to a supply of 220 V, a steady current of 2 A passes in it and temperature is 500oC more than room temperature. what is the temperature coeffic...

In a circuit for finding the resistance of a galvanometer by half deflection method, a 6 V battery and a high resistance of 11 k\(\Omega\) are used. The figure of merit of the galvanometer is 60 \(\mu A/\)division. In the absence of shu...

In a meter bridge, as shown in the figure, it is given that resistance \(Y = 12.5\,\,\Omega\) and that the balance is obtained at a distance \(39.5\) \(cm\) from end \(A\) (by Jockey J). After interchanging the resistances \(X\) and $$Y$...

In the given circuit all resistances are of value \(R\) \(ohm\) each. The equivalent resistance between \(A\) and \(B\) is :

A copper rod of cross-sectional area A carries a uniform current I through it. At temperature T, if the volume charge density of the rod is \(\rho\), how long will the changes take to travel a distance d ?

A constant voltages is applied between two ends of a metallic wire. If the length is halved and the radius of the wire is doubled, the rate of heat developed in the wire will be :

On interchanging the resistances, the balance point of a meter bridge shifts to the left by 10 cm. The
resistance of their series combination is 1 k\(\Omega\). How much was the resistance on the left slot before
interchanging the resistanc...

In a potentiometer experiment, it is found that no current passes through the galvanometer when the
terminals of the cell are connected across 52 cm of the potentiometer wire. If the cell is shunted by a
resistance of 5 \(\Omega\), a balanc...

Two batteries with e.m.f 12 V and 13 V are connected in parallel across a load resistor of 10 \(\Omega\). The
internal resistances of the two batteries are 1 \(\Omega\) and 2 \(\Omega\) respectively. The voltage across the load lies betw...

A uniform wire of length 1 and radius r has a resistance of 100 \(\Omega\). It is recast into a wire of radius \({r \over 2}.\) The resistance of new wire will be :

The figure shows three circuits I, II and III which are connected to a 3V battery. If the powers dissipated by the configurations I, II and III are P1 , P2 and P3 respectively, then :

In a meter bridge experiment resistances are connected as shown in the figure. Initially resistance P = 4 \(\Omega\) and the neutral point N is at 60 cm from A. Now an unknown resistance R is connected in series to P and the new position o...

A 9 V battery with internal resistance of 0.5 \(\Omega\) is connected across an infinite network as shown in the figure. All ammeters A1, A2,
3 and voltmeter V are ideal.
Choose correct statement.

A potentiometer PQ is set up to compare two resistances as shown in the figure. The ammeter A in the circuit reads 1.0 A when two way key K3 is open. The balance point is at a length \(\ell\)1 cm from P when two way key K3 is plugged in...

In the given circuit, the current in each resistance is:

Which of the following statements is false?

When a current of 5 mA is passed through a galvanometer having a coil of resistance 15\(\Omega\), it shows full
scale deflection. The value of the resistance to be put in series with the galvanometer to convert it into a
voltmeter of range...

In the circuit shown, the resistance r is a variable resistance. If for r = fR, the heat generation in r is maximum then the value of f is :

A 50 \(\Omega\) resistance is connected to a battery of 5 V. A galvanometer of resistance 100 \(\Omega\) is to be used as an ammeter to measure current through the resistance, for this a resistance rs is connected to the galvanometer. Whi...

The resistance of an electrical toaster has a temperature dependence given by R(T) = R0 [1 + \(\alpha\)(T − T0)] in its range of operation. At T0 = 300 K, R = 100 \(\Omega\) and at T = 500 K, R = 120 \(\Omega\). The toaster is connected ...

A galvanometer has a 50 division scale. Battery has no internal resistance. It is found that there is deflection of 40 divisions when R = 2400 \(\Omega\). Deflection becomes 20 divisions when resistance taken from resistance box is 4900 $$...

A galvanometer having a coil resistance of \(100\,\Omega\) gives a full scale deflection, when a currect of \(1\) \(mA\) is passed through it. The value of the resistance, which can convert this galvanometer into ammeter giving a full scal...

When \(5V\) potential difference is applied across a wire of length \(0.1\) \(m,\) the drift speed of electrons is \(2.5 \times {10^{ - 4}}\,\,m{s^{ - 1}}.\) If the electron density in the wire is \(8 \times {10^{28}}\,\,{m^{ - 3}},\) the r...

In the circuit shown, the current in the \(1\Omega\) resistor is :

In a large building, three are \(15\) bulbs of \(40\) \(W\), \(5\) bulbs of \(100\) \(W\), \(5\) fans of \(80\) \(W\) and \(1\) heater of \(1\) \(kW.\) The voltage of electric mains is \(220\) \(V.\) The minimum capacity of the main fuse of...

The supply voltage to room is \(120V.\) The resistance of the lead wires is \(6\Omega\). A \(60\) \(W\) bulb is already switched on. What is the decrease of voltage across the bulb, when a \(240\) \(W\) heater is switched on in parallel t...

This questions has Statement - \({\rm I}\) and Statement - \({\rm I}\)\({\rm I}\). Of the four choices given after the Statements, choose the one that best describes into two Statements.
Statement - \({\rm I}\) : Higher the range, greater ...

Two electric bulbs marked \(25W\) \(-\) \(220\) \(V\) and \(100W\) \(-\) \(220V\) are connected in series to a \(440\) \(V\) supply. Which of the bulbs will fuse?

If a wire is stretched to make it \(0.1\%\) longer, its resistance will:

Two conductors have the same resistance at \({0^ \circ }C\) but their temperature coefficients of resistance are \({\alpha _1}\) and \({\alpha _2}.\) The respective temperature coefficients of their series and parallel combinations are near...

Shown in the figure below is a meter-bridge set up with null deflection in the galvanometer.

The value of the unknown resister \(R\) is

Consider a block of conducting material of resistivity \('\rho '\) shown in the figure. Current \('I'\) enters at \('A'\) and leaves from \('D'\). We apply superposition principle to find voltage \('\Delta V'\) developed between \('B'\) and...

Consider a block of conducting material of resistivity \('\rho '\) shown in the figure. Current \('I'\) enters at \('A'\) and leaves from \('D'\). We apply superposition principle to find voltage \('\Delta V'\) developed between \('B'\) and...

A \(5V\) battery with internal resistance \(2\Omega\) and a \(2V\) battery with internal resistance \(1\Omega\) are connected to a \(10\Omega\) resistor as shown in the figure.

The current in the \(10\Omega\) resistor is

The resistance of a wire is \(5\) ohm at \({50^ \circ }C\) and \(6\) ohm at \({100^ \circ }C.\) The resistance of the wire at \({0^ \circ }C\) will be

The current \({\rm I}\) drawn from the \(5\) volt source will be

A thermocouple is made from two metals, Antimony and Bismuth. If one junction of the couple is kept hot and the other is kept cold, then, an electric current will

The resistance of bulb filmanet is \(100\Omega\) at a temperature of \({100^ \circ }C.\) If its temperature coefficient of resistance be \(0.005\) per \(^ \circ C\), its resistance will become \(200\,\Omega\) at a temperature of

An electric bulb is rated \(220\) volt - \(100\) watt. The power consumed by it when operated on \(110\) volt will be

In a Wheatstone's bridge, three resistance \(P, Q\) and \(R\) connected in the three arms and the fourth arm is formed by two resistances \({S_1}\) and \({S_2}\) connected in parallel. The condition for the bridge to be balanced will be