Current Electricity Practice Questions

Three voltmeters, all having different internal resistances are joined as shown in figure. When some potential difference is applied across ${\text{A}}$ and $B$, their readings are $V_1, V_2$ and $V_3$. Choose the correct option. [27-Jan-2024 Shift 2]

An electric toaster has resistance of $60 Ω$ at room temperature $(27^{\circ} {\text{C}})$. The toaster is connected to a $220 {\text{V}}$ supply. If the current flowing through it reaches $2.75 {\text{A}}$, the temperature attained by toaster is around : (if $\alpha =2 \times 10^{-4} /{ }^{\circ} {\text{C}}$ ) [30-Jan-2024 Shift 1]

The resistance per centimeter of a meter bridge wire is ${\text{r}}$, with ${\text{X}} Ω$ resistance in left gap. Balancing length from left end is at $40 {\text{cm}}$ with $25 Ω$ resistance in right gap. Now the wire is replaced by another wire of $2 {\text{r}}$ resistance per centimeter. The new balancing length for same settings will be at [31-Jan-2024 Shift 2]

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

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

The current in a conductor is expressed as $I=3 t^{2+}4 t^3$, 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 ${\text{t}}=2 {\ s}$ is _______C. [1-Feb-2024 Shift 1]

Two resistance of $100 Ω$ and $200 Ω$ are connected in series with a battery of $4 {\text{V}}$ and negligible internal resistance. A voltmeter is used to measure voltage across $100 Ω$ resistance, which gives reading as $1 {\text{V}}$. The resistance of voltmeter must be ______$Ω$ [30-Jan-2024 Shift 2]

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

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

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

A wire of resistance $20 Ω$ 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 _____ $Ω$.

Equivalent resistance of the following network is $Ω$. [31-Jan-2024 Shift 1]

In the given figure $R_1=10 Ω, R_2=8 Ω, R_3=4 Ω$ and ${\text{R}}_4=8 Ω$. Battery is ideal with emf $12 {\text{V}}$. Equivalent resistant of the circuit and current supplied by battery are respectively.

Two cells are connected in opposition as shown. Cell ${\text{E}}_1$ is of $8 {\text{V}}$ emf and $2 Ω$ internal resistance; the cell ${\text{E}}_2$ is of $2 {\text{V}}$ emf and $4 Ω$ internal resistance. The terminal potential difference of cell ${\text{E}}_2$ is: [30-Jan-2024 Shift 1]

A wire of length $10 {\text{cm}}$ and radius ${\sqrt{7}} \times 10^{-4} {\text{m}}$ connected across the right gap of a meter bridge. When a resistance of $4.5 Ω$ is connected on the left gap by using a resistance box, the balance length is found to be at $60 {\text{cm}}$ from the left end. If the resistivity of the wire is ${\text{R}} \times 10^{-7} Ω {\text{m}}$, then value of ${\text{R}}$ is : [27-Jan-2024 Shift 1]

In an experiment to find emf of a cell using potentiometer, the length of null point for a cell of emf $1.5 {\text{V}}$ is found to be $60 {\text{cm}}$. If this cell is replaced by another cell of emf $E$. the length-of null point increases by $40 {\text{cm}}$. The value of $E$ is $\;\frac{x}{10} {\text{V}}$. The value of $x$ is ________. [1-Feb-2023 Shift 1]

Two identical cells each of emf $1.5 {\text{V}}$ are connected in series across a $10 Ω$ resistance. An ideal voltmeter connected across $10 Ω$ resistance reads $1.5 {\text{V}}$. The internal resistance of each cell is ________ $Ω$. [11-Apr-2023 shift 2]

As shown in the figure, a network of resistors is connected to a battery of $24 {\text{V}}$ with an internal resistance of $3 Ω$. The currents through the resistors ${\text{R}}_{4}$ and ${\text{R}}_{5}$ are ${\text{I}}_{4}$ and ${\text{I}}_{5}$ respectively. The values of ${\text{I}}_{4}$ and ${\text{I}}_{5}$ are : $(24 {\text{V}}, 3 Ω)$ [24-Jan-2023 Shift 1]