Current Electricity

In the given circuit, an ideal voltmeter connected across $6 \Omega$ reads 5 V . The internal resistance $r$ of each cell is:

A current of 3 A enters one vertex P of an equilateral triangle PQR having three resistors of $1 \Omega$ each forming the sides of the equilateral triangle as shown. The value of $i_2$ in amperes is:

Current in a conductor is expressed as $I=8 t^3+3 t^2+2$, where current I is measured in amperes and time t is measured in seconds. What is the charge that flows through a cross-section of the conductor between time $t=1 \mathrm{~s}$ to $t=...

A wire of length 1 m has a resistance of $20 \Omega$ at $0^{\circ} \mathrm{C}$. It is uniformly stretched so that its length increases by $21 \%$. Assuming the volume of the wire remains constant, the percentage change in resistance is $n \...

The voltage - current graph for a metal wire of uniform area of cross section at two different temp $T$ and $T^{\prime}$ is shown.
Then choose the correct statement:

An electric coil is rated $400 \mathrm{~W}, 200 \mathrm{~V}$. It is cut into two equal parts and connected in parallel to the same source of 200 V . Calculate the percentage increase in energy produced per second.

A parallel combination of ' $n$ ' cells of emf ' $E$ ' and internal resistance ' $r$ ' each, are connected across the external resistance ' $R$ '. If the external resistance ' $R$ ' is negligibly small, then the current ' $I$ ' through the ...

The dimensional formula for specific resistance is:

A galvanometer of resistance $50 \Omega$ is connected to a battery of 4 V along with a resistance of $3950 \Omega$ in series. A full-scale deflection of 30 divisions is obtained in the galvanometer. In order to reduce this deflection to 10 ...

Two identical conductors of lengths 1 and 31 respectively are maintained at the same temperature. They are given potential differences in the ratio $1: 3$. The ratio of their drift velocities is

The resistance of a wire is 5 ohm at $25^{\circ} \mathrm{C}$ and 7 ohm at $100^{\circ} \mathrm{C}$. The resistance of the wire at $0^{\circ} \mathrm{C}$ is

If voltage across a bulb rated $220 \mathrm{~V}, 50 \mathrm{~W}$ drops by $5 \%$ of its rated value, the percentage of the rated value by which the power would decrease is

A student measures the terminal potential difference $V$ of a cell (emf $\varepsilon$ and internal resistance $r$ ) as a function of current I flowing through it, and draws V versus I graph. The slope and intercept of the graph respectively...

A student measures the terminal potential difference $V$ of a cell of emf $\varepsilon$ and internal resistance $r$ as a function of the current I flowing through it. Which of the following graphs will give the values of emf $\varepsilon$ a...

The net resistance between the points A and B in the circuit given below is:

The power dissipated across the $16 \Omega$ resistor in the circuit is 2 watts. The power dissipated in watt units across the $4 \Omega$ resistor is:

A galvanometer having a resistance of $50 \Omega$ is shunted by a wire of resistance $10 \Omega$. If the total current is 2 A , the current passing through the shunt is:

The resistance of a heating element is found to be $120 \Omega$ at room temperature which is $20^{\circ} \mathrm{C}$. If the temperature coefficient of the material of the resistor is $1.6 \times 10^{-4} C^{-1}$ and the resistance is found ...

Two wires A and B made of same material having length 10 cm and 40 cm respectively are connected in parallel to the same source of emf 10 V . What will be the ratio of the drift velocity of the electrons in the wire $A$ to the drift velocit...

Ten cells, each having internal resistance $1 \Omega$ and emf 1.5 V are connected in series. But unknowingly 3 cells are connected wrongly in series. The effective internal resistance and emf of the series combination are respectively:

The resistance of the conductor is $\sqrt{3} \Omega$ the angle made by the V-I graph with the voltage axis is $\theta$

The wire made of Phosphor bronze is used as the suspension strip in the moving coil galvanometer, because:

A galvanometer of $50 \Omega$ resistance is converted into an ammeter using a shunt resistance of $10 \Omega$. If the same resistance is used to convert the same galvanometer in to a voltmeter, what would be the ratio of the resistance of t...

Across the 220 V source of internal resistance $20 \Omega$, how many lamps of $40 \mathrm{~W}, 100 \mathrm{~V}$ can be connected in parallel so that all the lamps may glow with full brightness.

The current through a conductor is '\(\mathrm{a}\)' when the temperature is \(0^{\circ} \mathrm{C}\). It is '\(\mathrm{b}\)' when the temperature is \(100^{\circ} \mathrm{C}\). The current through the conductor at \(220^{\circ} \mathrm{C}\)...

On increasing the temperature of a conductor, its resistance increases because

The resistance of the galvanometer and shunt of an ammeter are \(90 \mathrm{~ohm}\) and \(10 \mathrm{~ohm}\) respectively, then the fraction of the main current passing through the galvanometer and the shut respectively are:

A cell of emf E and internal resistance r is connected to two external resistances \(\mathrm{R_1}\) and \(\mathrm{R_2}\) and a perfect ammeter. The current in the circuit is measured in four different situations:
(a) without any external re...

A \(500 \mathrm{~W}\) heating unit is designed to operate on a \(400 \mathrm{~V}\) line. If line voltage drops to \(160 \mathrm{~V}\), the percentage drop in heat output will be:

Four resistors, each of resistance R, are connected as shown in the figure below.

Three bulbs of \(40 \mathrm{~W}, 60 \mathrm{~W}\), and \(100 \mathrm{~W}\) are arranged in series with a \(220 \mathrm{~V}\) source. The maximum light is obtained from

A voltmeter of resistance \(1000 \Omega .0 .5 \mathrm{~V} /\) div is to be converted into a voltmeter to make it to read \(=1 \mathrm{~V} / \mathrm{div}\). The value of high resistance to be connected in series with it is

The resistance of a \(10 \mathrm{~m}\) long wire is \(10 \Omega\). Its length is increased by \(25 \%\) by stretching the wire uniformly. The new resistance is

The potential difference between the points \(\mathrm{P}\) and \(\mathrm{Q}\) of the arrangement shown in figure is

A wire of uniform cross section and resistance 4 ohms is bent in the shape of square ABCD. Point A is connected to a point \(\mathrm{P}\) on DC by a wire AP of resistance \(1 \mathrm{ohm}\). When a potential difference is applied between $$...

An electron starting from rest and moving with the velocity \(\mathrm{v}\) through a potential difference \(\mathrm{V}\) is shown by the graphs below. Identify the correct graph.

Two identical moving coil galvanometers have \(10 \Omega\) resistance and full-scale deflection at \(2 \mu \mathrm{A}\) current. One of them is converted into a voltmeter of range \(10 \mathrm{~mV}\) and the other into an ammeter of range $...

A storage battery of emf \(28.0 \mathrm{~V}\) and internal resistance \(0.5 \Omega\) is being charged by a \(140 \mathrm{~V}\) dc supply using a series resistor of \(27.5 \Omega\). The terminal voltage of the battery during charging is

The resistance of a wire at room temperature \(20^{\circ} \mathrm{C}\) is found to be \(10 \Omega\). If resistance of the wire increases by \(10 \%\), then the temperature of the wire will be (The temperature coefficient of the material of ...

The current passing through the 100\(\Omega\) resistor in the given electrical circuit is :

The current drawn by the primary coil of an ideal transformer, which steps up \(22 \mathrm{~V}\) into \(220 \mathrm{~V}\), to operate a device having a load resistance \(110 \Omega\) is:

A battery is made of 12 cells having emf \(5 \mathrm{~V}\) each. If three cells are unknowingly connected wrong, the resultant emf of the battery will be:

The SI unit of electrical conductivity is :

A resistor of wire \(24 \mathrm{~cm}\) length and resistance \(8 \Omega\) is stretched in to a uniform wire of \(48 \mathrm{~cm}\) length, then the new resistance will be :

The electric flux from cube of side \(1 \mathrm{~m}\) is '\(\Phi\)' When the side of the cube is made \(3 \mathrm{~m}\) and the charge enclosed by the cube is made one third of the original value, then the flux from the bigger cube will be ...

The current sensitivity of a galvanometer having 20 divisions is \(10 \mu \mathrm{A} /\) div. If the resistance of the galvanometer is \(100 \Omega\) then the value of the resistance to be used to convert this galvanometer in to an voltmete...

Two cells with the same emf \(E\) and different internal resistances \(r_1\) and \(r_2\) are connected in series to an external resistance \(R\). If the potential difference across the first cell is zero then value of \(R\).

A galvanometer having a resistance of \(8 \Omega\) is shunted by a wire of resistance \(2 \Omega\). If the total current is \(1 \mathrm{~A}\), the part of it passing through the shunt will be

A cell of emf 2 V is connected with a load of resistance 1.5 \(\Omega\). The power delivered by the cell to the load is maximum, then power transferred to the load is

A galvanometer having a resistance of 4 \(\Omega\) is shunted by a wire of resistance 2 \(\Omega\). If the total current is 1.5 A, the current passing through shunt is