Current Electricity — JEE Main PYQs

The reading in the ideal voltmeter (V) shown in the given circuit diagram is:

A galvanometer has a resistance of $50\Omega$ and it allows maximum current of 5 mA. It can be converted into voltmeter to measure upto 100 V by connecting in series a resistor of resistance

The current in a conductor is expressed as $I=3t^2+4t^3$, where $I$ is in Ampere and $t$ is in second. The amount of electric charge that flows through a section of the conductor during $t=1$ s to $t=2$ s is ______ C.

In the given circuit, the voltage across load resistance $({\mathrm{R}}_{\mathrm{L}})$ is:

When a potential difference V is applied across a wire of resistance R , it dissipates energy at a rate W . If the wire is cut into two halves and these halves are connected mutually parallel across the same supply, the energy dissipation rate will become:

Two resistance of $100\Omega$ and $200\Omega$ are connected in series with a battery of 4 V and negligible internal resistance. A voltmeter is used to measure voltage across $100\Omega$ resistance, which gives reading as 1 V. The resistance of voltmeter must be $\_\_\_\_$ …

A potential divider circuit is shown in figure. The output voltage ${\mathrm{V}}_0$ is

An electric toaster has resistance of $60\Omega$ at room temperature $\left(27^{\circ }\mathrm{C}\right)$. The toaster is connected to a 220 V supply. If the current flowing through it reaches 2.75 A , the temperature attained by toaster is around : (if …

Two cells are connected in opposition as shown. Cell ${\mathrm{E}}_1$ is of 8 V emf and $2\Omega$ internal resistance; the cell ${\mathrm{E}}_2$ is of 2 V emf and $4\Omega$ internal resistance. The terminal potential difference of cell ${\mathrm{E}}_2$ is:

The resistance per centimeter of a meter bridge wire is r, with $X\Omega$ resistance in left gap. Balancing length from left end is at 40 cm with $25\Omega$ resistance in right gap. Now the wire is replaced by another wire of $2r$ resistance per centimeter. The new balancing leng …

By what percentage will the illumination of the lamp decrease if the current drops by $20\%$?

In the following circuit, the battery has an emf of 2 V and an internal resistance of $\frac{2}{3}\Omega$. The power consumption in the entire circuit is ______ W.

For a given transistor amplifier circuit in CE configuration ${\mathrm{V}}_{\mathrm{CC}}=1\mathrm{V},{\mathrm{R}}_{\mathrm{c}}=1\mathrm{k}\Omega ,{\mathrm{R}}_{\mathrm{b}}=100\mathrm{k}\Omega$ and $\beta =100$. Value of base current ${\mathrm{I}}_{\mathrm{b}}$ is

The equivalent resistance between A and B as shown in figure is:

The number density of free electrons in copper is nearly $8\times 10^{28}{\mathrm{m}}^{-3}$. A copper wire has its area of cross section $=2\times 10^{-6}{\mathrm{m}}^2$ and is carrying a current of 3.2 A . The drift speed of the electrons is ____ …

Certain galvanometers have a fixed core made of non magnetic metallic material. The function of this metallic material is

A current of 2 A flows through a wire of cross-sectional area $25.0{\mathrm{mm}}^2$. The number of free electrons in a cubic meter are $2.0\times 10^{28}$. The drift velocity of the electrons is $\_\_\_\_$ $\times 10^{-6}{\mathrm{ms}}^{-1}$ (given, charge on electron …

Figure shows a part of an electric circuit. The potentials at points $\mathrm{a}$, $\mathrm{b}$ and c are $30\mathrm{V}$, $12\mathrm{V}$ and 2 V respectively. The current through the $20\Omega$ resistor will be.

A student is provided with a variable voltage source V, a test resistor ${\mathrm{R}}_{\mathrm{r}}=10\Omega$, two identical galvanometers ${\mathrm{G}}_1$ and ${\mathrm{G}}_2$ and two additional resistors, ${\mathrm{R}}_1=10\mathrm{M}\Omega$ and ${\mathrm{R}}_2=0.001\Omega$. Fo …

As shown in the figure, the voltmeter reads 2 V across $5\Omega$ resistor. The resistance of the voltmeter is ______ $\Omega$.

In a metallic conductor, under the effect of applied electric field, the free electrons of the conductor

If each diode has a forward bias resistance of $25\Omega$ in the below circuit,

Which of the following options is correct:

A rectangular parallelopiped is measured as 1 cm $\times$ 1 cm $\times$ 100 cm. If its specific resistance is $3\times 10^{-7}\Omega$ m, then the resistance between its two opposite rectangular faces will be ______ $\times 10^{-7}\Omega$.

Given below are two statement:

Statement I: If the number of turns in the coil of a moving coil galvanometer is doubled then the current sensitivity becomes double.
Statement II: Increasing current sensitivity of a moving coil galvanometer by only increasing the number of turns …

The equivalent resistance of the circuit shown below between points a and b is:

10 resistors each of resistance $10\Omega$ can be connected in such as to get maximum and minimum equivalent resistance. The ratio of maximum and minimum equivalent resistance will be $\_\_\_\_$.

Two identical heater filaments are connected first in parallel and then in series. At the same applied voltage, the ratio of heat produced in same time for parallel to series will be:

The current sensitivity of moving coil galvanometer is increased by $25\%$. This increase is achieved only by changing in the number of turns of coils and area of cross section of the wire while keeping the resistance of galvanometer coil constant. The percentage change in the …

In the circuit diagram shown in figure given below, the current flowing through resistance $3\Omega$ is $\frac{x}{3}\mathrm{A}$. The value of $x$ is ______.

A wire of resistance $160\Omega$ is melted and drawn in wire of one-fourth of its length. The new resistance of the wire will be

The current flowing through a conductor connected across a source is 2 A and 1.2 A at $0^{\circ }\mathrm{C}$ and $100^{\circ }\mathrm{C}$ respectively. The current flowing through the conductor at $50^{\circ }\mathrm{C}$ will be ____ $\times 10^2\mathrm{mA}$.

Different combination of 3 resistors of equal resistance $R$ are shown in the figures.
The increasing order for power dissipation is:

A potential $V_0$ is applied across a uniform wire of resistance R. The power dissipation is $P_1$. The wire is then cut into two equal halves and a potential of $V_0$ is applied across the length of each half. The total power dissipation across two wires is $P_2$. The ratio …

When a resistance of $5\Omega$ is shunted with a moving coil galvanometer, it shows a full scale deflection for a current of 250 mA, however when $1050\Omega$ resistance is connected with it in series, it gives full scale deflection for 25 volt. The resistance of galvanometer is …

In the circuit shown, the energy stored in the capacitor is $n\mu J$. The value of $n$ is ______.

For designing a voltmeter of range 50 V and an ammeter of range 10 mA using a galvanometer which has a coil of resistance $54\Omega$ showing a full scale deflection for 1 mA as in figure.

(A) for voltmeter $R\approx 50k\Omega$
(B) for ammeter $r\approx 0.2\Omega$
(C) for am …

Given below are two statements:

Statement I: The equivalent resistance of resistors in a series combination is smaller than least resistance used in the combination.

Statement II: The resistivity of the material is independent of temperature.
In the light of the above statement …

In the given circuit, the current (I) through the battery will be :

A network of four resistances is connected to 9 V battery, as shown in figure. The magnitude of voltage difference between the points A and B is ______ V.

The length of a metallic wire is increased by $20\%$ and its area of cross section is reduced by $4\%$. The percentage change in resistance of the metallic wire is

The current flowing through ${\mathrm{R}}_2$ is:

Two identical cells each of emf 1.5 V are connected in series across a $10\Omega$ resistance. An ideal voltmeter connected across $10\Omega$ resistance reads 1.5 V . The internal resistance of each cell is
$\_\_\_\_$ $\Omega$.

The equivalent resistance between $A$ and $B$ of the network shown in figure:

In an experiment to find emf of a cell using potentiometer, the length of null point for a cell of emf 1.5 V is found to be 60 cm . If this cell is replaced by another cell of emf $E$. the length-of null point increases by 40 cm . The value of $E$ is …

As shown in the figure, a network of resistors is connected to a battery of 24 V with an internal resistance of $3\Omega$. The currents through the resistors ${\mathrm{R}}_4$ and ${\mathrm{R}}_5$ are ${\mathrm{I}}_4$ and ${\mathrm{I}}_5$ respectively. The values of …

A hollow cylindrical conductor has length of 3.14 m, while its inner and outer diameters are 4 mm and 8 mm respectively. The resistance of the conductor is $n\times 10^{-3}\Omega$.
If the resistivity of the material is $2.4\times 10^{-8}\Omega \mathrm{m}$. The value of $n$ i …

A cell of emf 90 V is connected across series combination of two resistors each of $100\Omega$ resistance. A voltmeter of resistance $400\Omega$ is used to measure the potential difference across each resistor. The reading of the voltmeter will be :

If a copper wire is stretched to increase its length by $20\%$. The percentage increase in resistance of the wire is ______ %.

A uniform metallic wire carries a current 2 A. when 3.4 V battery is connected across it. The mass of uniform metallic wire is $8.92\times 10^{-3}\mathrm{kg}$. density is $8.92\times 10^3\mathrm{kg}/{\mathrm{m}}^3$ and resistivity is $1.7\times 10^{-8}\Omega$-m. The l …

In the given circuit, the equivalent resistance between the terminal A and B is $\_\_\_\_$ $\Omega$.