Current Electricity — JEE Main PYQs

Two cells of emf 1 V and 2 V and internal resistance $2\Omega$ and $1\Omega$, respectively, are connected in series with an external resistance of $6\Omega$. The total current in the circuit is $I_1$. Now the same two cells in parallel configuration are connected to …

Current passing through a wire as function of time is given as $I(t)=0.02t+0.01\text{ A}$. The charge that will flow through the wire from $t=1\text{ s}$ to $t=2\text{ s}$ is :

A wire of resistance R is bent into a triangular pyramid as shown in figure with each segment having same length. The resistance between points A and B is R/n. The value of n is:

There are 'n' number of identical electric bulbs, each is designed to draw a power p independently from the mains supply. They are now joined in series across the main supply. The total power drawn by the combination is :

From the combination of resistors with resistance values ${\mathrm{R}}_1={\mathrm{R}}_2={\mathrm{R}}_3=5\Omega$ and ${\mathrm{R}}_4=10\Omega$, which of the following combination is the best circuit to get an equivalent resistance of $6\Omega$ ?

The number of electrons per second in the filament of a 110 W bulb operating at 220 V is : (Given $\mathrm{e}=1.6\times 10^{-19}\mathrm{C}$ )

In the given figure an ammeter A consists of a $240\Omega$ coil connected in parallel to a $10\Omega$ shunt. The reading of the ammeter is ______ mA.

An electric bulb rated $50\mathrm{W}-200\mathrm{V}$ is connected across a 100 V supply. The power dissipation of the bulb is :

Two wires A and B are made up of the same material and have the same mass. Wire A has radius of 2.0 mm and wire $B$ has radius of 4.0 mm. The resistance of wire B is $2\Omega$. The resistance of wire A is ____ $\Omega$.

The resistances of the platinum wire of a platinum resistance thermometer at the ice point and steam point are $8\Omega$ and $10\Omega$ respectively. After inserting in a hot bath of temperature $400^{\circ }\mathrm{C}$, the resistance of platinum wire is :

To measure the internal resistance of a battery, potentiometer is used. For $\mathrm{R}=10\Omega$, the balance point is observed at $\ell =500\mathrm{cm}$ and for $\mathrm{R}=1\Omega$ the balance point is observed at $\ell =400\mathrm{cm}$. The internal resistance of …

The value of net resistance of the network as shown in the given figure is :

Twelve wires each having resistance $2\Omega$ are joined to form a cube. A battery of 6 V emf is joined across point a and c. The voltage difference between e and f is ______ V.

A galvanometer of resistance $100\Omega$ when connected in series with $400\Omega$ measures a voltage of upto 10 V . The value of resistance required to convert the galvanometer into ammeter to read upto 10 A is $\mathrm{x}\times 10^{-2}\Omega$. The value of x is :

The ratio of heat dissipated per second through the resistance $5\Omega$ and $10\Omega$ in the circuit given below is :

A wire of resistance $20\Omega$ is divided into 10 equal parts. A combination of two parts are connected in parallel and so on. Now resulting pairs of parallel combination are connected in series. The equivalent resistance of final combination is ____ $\Omega$.

In the given figure ${\mathrm{R}}_1=10\Omega$, ${\mathrm{R}}_2=8\Omega$, ${\mathrm{R}}_3=4\Omega$ and ${\mathrm{R}}_4=8\Omega$. Battery is ideal with emf 12 V. Equivalent resistant of the circuit and current supplied by battery are respectively.

The electric field between the two parallel plates of a capacitor of $1.5\mu \mathrm{F}$ capacitance drops to one third of its initial value in $6.6\mu \mathrm{s}$ when the plates are connected by a thin wire. The resistance of this wire is ______ $\Omega$. (Given, …

In the experiment to determine the galvanometer resistance by half-deflection method, the plot of $\frac{1}{\theta }$ vs the resistance (R) of the resistance box is shown in the figure. The figure of merit of the galvanometer is ______ $\times 10^{-1}\mathrm{A}$/division. [T …

The value of unknown resistance ( x ) for which the potential difference between B and D will be zero in the arrangement shown, is :

A wire of resistance R and radius r is stretched till its radius became $r/2$. If new resistance of the stretched wire is x R, then value of x is ______.

In the given circuit, the terminal potential difference of the cell is :

Resistance of a wire at $0^{\circ }\mathrm{C}$, $100^{\circ }\mathrm{C}$ and ${\mathrm{t}}^{\circ }\mathrm{C}$ is found to be $10\Omega$, $10.2\Omega$ and $10.95\Omega$ respectively. The temperature t in Kelvin scale is ____.

Water boils in an electric kettle in 20 minutes after being switched on. Using the same main supply, the length of the heating element should be
____ to ____ times of its initial length if the water is to be boiled in 15 minutes.

A heater is designed to operate with a power of 1000 W in a 100 V line. It is connected in combination with a resistance of $10\Omega$ and a resistance R, to a 100 V mains as shown in figure. For the heater to operate at 62.5 W, the value of R should be ______ $\Omega$.

A galvanmeter has a coil of resistance $200\Omega$ with a full scale deflection at $20\mu \mathrm{A}$. The value of resistance to be added to use it as an ammeter of range $(0-20)$ mA is:

The equivalent resistance between A and B is:

The current flowing through the $1\Omega$ resistor is $\frac{\mathrm{n}}{10}$ A. The value of $n$ is ____.

The effective resistance between $A$ and $B$, if resistance of each resistor is $R$, will be

To determine the resistance ( R ) of a wire, a circuit is designed below, The V-I characteristic curve for this circuit is plotted for the voltmeter and the ammeter readings as shown in figure. The value of R is ______ $\Omega$.

At room temperature $\left(27^{\circ }\mathrm{C}\right)$, the resistance of a heating element is $50\Omega$. The temperature coefficient of the material is $2.4\times 10^{-4}{}^{\circ }{\mathrm{C}}^{-1}$. The temperature of the element, when its resistance is $62\Omega$ …

Wheatstone bridge principle is used to measure the specific resistance (${\mathrm{S}}_1$) of given wire, having length L, radius r. If X is the resistance of wire, then specific resistance is: ${\mathrm{S}}_1=\mathrm{X}\left(\frac{\pi {\mathrm{r}}^2}{\mathrm{L}}\right)$. If …

A current of $200\mu \mathrm{A}$ deflects the coil of a moving coil galvanometer through $60^{\circ }$. The current to cause deflection through $\frac{\pi }{10}$ radian is :

Three voltmeters, all having different internal resistances are joined as shown in figure. When some potential difference is applied across A and B, their readings are $V_1,V_2$ and $V_3$. Choose the correct option.

In the given circuit, the current in resistance ${\mathrm{R}}_3$ is:

In the given circuit, the current flowing through the resistance $20\Omega$ is 0.3 A , while the ammeter reads 0.9 A . The value of ${\mathrm{R}}_1$ is ______ $\Omega$.

A wire of length 10 cm and radius $\sqrt{7}\times 10^{-4}\mathrm{m}$ connected across the right gap of a meter bridge. When a resistance of $4.5\Omega$ is connected on the left gap by using a resistance box, the balance length is found to be at 60 cm from the left end. If …

A wire of resistance R and length L is cut into 5 equal parts. If these parts are joined parallely, then resultant resistance will be :

The charge accumulated on the capacitor connected in the following circuit is ______ $\mu \mathrm{C}$ (Given $\mathrm{C}=150\mu \mathrm{F}$)

In the given circuit, the breakdown voltage of the Zener diode is 3.0 V. What is the value of ${\mathrm{I}}_{\mathrm{z}}$?

The electric current through a wire varies with time as $\mathrm{I}={\mathrm{I}}_0+\beta \mathrm{t}$, where ${\mathrm{I}}_0=20\mathrm{A}$ and $\beta =3\mathrm{A}/\mathrm{s}$. The amount of electric charge crossed through a section of the wire in 20 s is:

A galvanometer having coil resistance $10\Omega$ shows a full scale deflection for a current of 3 mA. For it to measure a current of 8 A, the value of the shunt should be:

The deflection in moving coil galvanometer falls from 25 divisions to 5 division when a shunt of $24\Omega$ is applied. The resistance of galvanometer coil will be :

A $16\Omega$ wire is bend to form a square loop. A 9 V battery with internal resistance $1\Omega$ is connected across one of its sides. If a $4\mu \mathrm{F}$ capacitor is connected across one of its diagonals, the energy stored by the capacitor will be …

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

Equivalent resistance of the following network is ______ $\Omega$.

In an ammeter, $5\%$ of the main current passes through the galvanometer. If resistance of the galvanometer is G , the resistance of ammeter will be :

To measure the temperature coefficient of resistivity $\alpha$ of a semiconductor, an electrical arrangement shown in the figure is prepared. The arm BC is made up of the semiconductor. The experiment is being conducted at $25^{\circ }\mathrm{C}$ and resistance of the semicon …

In a metre-bridge when a resistance in the left gap is $2\Omega$ and unknown resistance in the right gap, the balance length is found to be 40 cm. On shunting the unknown resistance with $2\Omega$, the balance length changes by :

A moving coil galvanometer has 100 turns and each turn has an area of $2.0{\mathrm{cm}}^2$. The magnetic field produced by the magnet is 0.01 T and the deflection in the coil is 0.05 radian when a current of 10 mA is passed through it. The torsional constant of the suspension …