Current Electricity — JEE Main PYQs

A resistor dissipates 192 J of energy in 1 s when a current of 4 A is passed through it. Now, when the current is doubled, the amount of thermal energy dissipated in 5 s in ______ J.

Consider a galvanometer shunted with $5\Omega$ resistance and $2\%$ of current passes through it. What is the resistance of the given galvanometer?

The voltage drop across $15\Omega$ resistance in the given figure will be _____ V.

A square shaped wire with resistance of each side $3\Omega$ is bent to form a complete circle. The resistance between two diametrically opposite points of the circle in unit of $\Omega$ will be _____.

A capacitor of $50\mu F$ is connected in a circuit as shown in figure. The charge on the upper plate of the capacitor is _____ $\mu C$.

In the given figure, a battery of emf E is connected across a conductor PQ of length 'ℓ' and different area of cross-sections by having radii $r_1$ and $r_2$ ($r_2<r_1$).

Choose the correct option as one moves from P to Q:

A capacitor of capacitance $\mathrm{C}=1\mu \mathrm{F}$ is suddenly connected to a battery of 100 volt through a resistance $\mathrm{R}=100\Omega$. The time taken for the capacitor to be charged to get 50 V is:
[Take $\ln 2=0.69$]

A current of 10 A exists in a wire of cross-sectional area of $5{\mathrm{mm}}^2$ with a drift velocity of $2\times 10^{-3}{\mathrm{ms}}^{-1}$. The number of free electrons in each cubic meter of the wire is:

The equivalent resistance of series combination of two resistors is ' $s$ '. When they are connected in parallel, the equivalent resistance is ' $p$ '. If $s=np$, then the minimum value for $n$ is ______ (Round off to the Nearest Integer)

In the given figure, there is a circuit of potentiometer of length $AB=10\mathrm{m}$. The resistance per unit length is $0.1\Omega$ per cm.
Across AB, a battery of emf E and internal resistance 'r' is connected. The maximum value of emf measured by this potentiometer is:

An electric bulb rated as 200 W at 100 V is used in a circuit having 200 V supply. The resistance '$R$' that must be put in series with the bulb so that the bulb delivers the same power is ____ $\Omega$.

In the given potentiometer circuit arrangement, the balancing length AC is measured to be 250 cm. When the galvanometer connection is shifted from point (1) to point (2) in the given diagram, the balancing length becomes 400 cm. The ratio of the emf of two cells, …

The given potentiometer has its wire of resistance $10\Omega$. When the sliding contact is in the middle of the potentiometer wire, the potential drop across $2\Omega$ resistor is:

A $16\Omega$ wire is bend to form a square loop. A 9 V supply having internal resistance of $1\Omega$ is connected across one of its sides. The potential drop across the diagonals of the square loop is _____ $\times 10^{-1}$ V.

The resistance of a conductor at $15^{\circ }\mathrm{C}$ is $16\Omega$ and at $100^{\circ }\mathrm{C}$ is $20\Omega$. What will be the temperature coefficient of resistance of the conductor ?

For the circuit shown, the value of current at time $t=3.2\mathrm{s}$ will be
____ A.

[Voltage distribution $\mathrm{V}(\mathrm{t})$ is shown by Fig.(1) and the circuit is shown in Fig.(2)]

In the given figure, each diode has a forward bias resistance of $30\Omega$ and infinite resistance in reverse bias. The current ${\mathrm{I}}_1$ will be:

A capacitor is connected to a 20 V battery through a resistance of $10\Omega$. It is found that the potential difference across the capacitor rises to 2 V in $1\mu \mathrm{s}$. The capacitance of the capacitor is ____ $\mu \mathrm{F}$.
Given …

A uniform heating wire of resistance $36\Omega$ is connected across a potential difference of 240 V. The wire is then cut into half and a potential difference of 240 V is applied across each half separately. The ratio of power dissipation in first case to the total power dissipa …

A conducting wire of length '$\ell$', area of cross-section A and electric resistivity $\rho$ is connected between the terminals of a battery. A potential difference V is developed between its ends, causing an electric current.
If the length of the wire of the same material i …

An RC circuit as shown in the figure is driven by a AC source generating a square wave. The output wave pattern monitored by CRO would look close to :

The value of power dissipated across the zener diode ( ${\mathrm{V}}_{\mathrm{z}}=15\mathrm{V}$ ) connected in the circuit as shown in the figure is $\mathrm{x}\times 10^{-1}$ watt.
The value of x , to the nearest integer, is ____

In the figure given, the electric current flowing through the 5 $\mathrm{k}\Omega$ resistor is ' x ' mA . The value of x to the nearest integer is ____

A resistor develops 500 J of thermal energy in 20 s when a current of 1.5 A is passed through it. If the current is increased from 1.5 A to 3 A , what will be the energy developed in 20 s .

The energy dissipated by a resistor is 10 mJ in 1 s when an electric current of 2 mA flows through it. The resistance is ____ $\Omega$. (Round off to the Nearest Integer)

Consider a 72 cm long wire AB as shown in the figure. The galvanometer jockey is placed at P on AB at a distance x cm from A. The galvanometer shows zero deflection.

The value of x, to nearest integer, is ____

Two wires of same length and thickness having specific resistance $6\Omega \mathrm{cm}$ and $3\Omega \mathrm{cm}$ respectively are connected in parallel. The effective resistivity is $\rho \Omega \mathrm{cm}$. The value of $\rho$, to the nearest integer, is ____

Two cells of emf 2E and E with internal resistance $r_1$ and $r_2$ respectively are connected in series to an external resistor R (see figure). The value of R , at which the potential difference across the terminals of the first cell becomes zero is

The four arms of a Wheatstone bridge have resistances as shown in the figure. A galvanometer of $15\Omega$ resistance is connected across BD. Calculate the current through the galvanometer when a potential difference of 10 V is maintained across AC.

The voltage across the $10\Omega$ resistor in the given circuit is $x$ volt.
The value of 'x' to the nearest integer is ______

The circuit shown in the figure consists of a charged capacitor of capacity $3\mu \mathrm{F}$ and a charge of $30\mu \mathrm{C}$. At time $\mathrm{t}=0$, when the key is closed, the value of current flowing through the $5\mathrm{M}\Omega$ resistor is 'x' …

The current $I_1$ (in A) flowing through $1\Omega$ resistor in the following circuit is

In a building there are 15 bulbs of $45\mathrm{W}$, 15 bulbs of $100\mathrm{W}$, 15 small fans of 10 W and 2 heaters of 1 kW. The voltage of electric main is 220 V. The minimum fuse capacity (rated value) of the building will be

In the figure, potential difference between A and B is:

The balancing length for a cell is 560 cm in a potentiometer experiment. When an external resistance of $10\Omega$ is connected in parallel to the cell, the balancing length changes by 60 cm. If the internal resistance of the cell is $\frac{\mathrm{N}}{10}\Omega$, where N is an …

The length of a potentiometer wire is 1200 cm and it carries a current of 60 mA . For a cell of emf 5 V and internal resistance of $20\Omega$, the null point on it is found to be at 1000 cm . The resistance of whole wire is:

Four resistances of $15\Omega ,12\Omega ,4\Omega$ and $10\Omega$ respectively in cyclic order to form Whetstone's network. The resistance that is to be connected in parallel with the resistance of $10\Omega$ to balance the network is ____ .

A galvanometer having a coil resistance $100\Omega$ gives a full scale deflection when a current of 1 mA is passed through it. What is the value of the resistance which can convert this galvanometer into a voltmeter giving full scale deflection for a potential difference of 10 V …

The series combination of two batteries, both of the same emf 10 V, but different internal resistance of $20\Omega$ and $5\Omega$, is connected to the parallel combination of two resistors 30 $\Omega$ and $\mathrm{R}\Omega$. The voltage difference across the battery of interna …

The current i in the network is:

Two identical capacitors A and B, charged to the same potential 5 V are connected in two different circuits as shown below at time $t=0$. If the charge on capacitors $A$ and $B$ at time $t=CR$ is $Q_A$ and $Q_B$ respectively, then (Here e is the base of natural logarithm)

In a meter bridge experiment S is a standard resistance. $R$ is a resistance wire. It is found that balancing length is $\ell =25$ cm. If $R$ is replaced by a wire of half length and half diameter that of R of same material, then the balancing distance ${\ell }^{\prime }$ (in cm) will now be …

The circuit as shown in figure is working as a 8 V dc regulated voltage source. When 12 V is used as input, the power dissipated (in mW) in each diode is (considering both zener diodes are identical) ____.

In the given circuit diagram, a wire is joining points $B$ and $D$. The current in this wire is:

A galvanometer is used in laboratory for detecting the null point in electrical experiments. If, on passing a current of 6 mA it produces a deflection of $2^{\circ }$, its figure of merit is close to:

In the circuit, given in the figure currents in different branches and value of one resistor are shown. Then potential at point $B$ with respect to the point $A$ is:

Model a torch battery of length $\ell$ to be made up of a thin cylindrical bar of radius 'a' and a concentric thin cylindrical shell of radius 'b' filled in between with an electrolyte of resistivity $\rho$ (see figure). If the battery is connected to a resistance of value R, the …

When a diode is forward biased, it has a voltage drop of 0.5 V. The safe limit of current through the diode is 10 mA. If a battery of emf 1.5 V is used in the circuit, the value of minimum resistance to be connected in series with the diode so that the current does not exceed the …

Two resistors $400\Omega$ and $800\Omega$ are connected in series across a 6 V battery. The potential difference measured by a voltmeter of $10\mathrm{k}\Omega$ across $400\Omega$ resistor is close to:

In the figure shown, the current in the 10 V battery is close to: