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Current Electricity - ISC Class 12 Physics Questions with Answers

100 past-paper questions on Current Electricity from ISC Class 12 Physics papers (2027-2018), newest first. Open one to see its answer.

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In the circuit shown in Figure 5 below, the central zero galvanometer G shows no deflection when the key K is closed. Calculate… 2027 · 3 marks · Numerical
Draw a labelled diagram of an arrangement used in Physics laboratory to compare emfs of two given cells X and Y. 2027 · 2 marks · Drawing
Three identical cells each of emf $1\cdot5\text{V}$ and internal resistance of $2\,\Omega$ are connected in series to form a… 2027 · 3 marks · Numerical
Heating power developed in a resistor R is given by $P = \frac{V^2}{R}$. This implies that the heating power is inversely… 2027 · 2 marks · Short answer
Compare resistance of an ideal voltmeter with that of an ideal ammeter. 2027 · 1 mark · Short answer
According to Ohm’s law, $V = IR$, so if potential difference (V) between the two ends of a metallic conductor is decreased, then… 2027 · 2 marks · Short answer
(a) Find the value of current 'I' in Figure 2 given below. (b) State the conservation principle on which your calculation is… 2026 · 2 marks · Short answer
In the circuit shown in Figure 4 below, how much resistance should be connected to a $10\Omega$ resistor so that the points M and… 2026 · 3 marks · Numerical
Two bulbs $B_{1}$ and $B_{2}$ having ratings (100W, 220V) and (200W, 220V) are connected in series to a 220V supply. Perform… 2026 · 2 marks · Numerical
What is the effect of doubling the current flowing through a metallic wire on: drift speed of free electrons? relaxation time of… 2026 · 2 marks · Short answer
Figure 4 below shows a uniform metallic wire AB which is 1m long. It has a resistance of $15\Omega$. It is connected in series… 2026 · 3 marks · Numerical
Using Kirchhoff’s laws of electrical networks, calculate the current $I_3$. (Application) 2026 · 3 marks · Numerical
Figure 5 below shows a battery consisting of three cells. Their emfs and internal resistances are also shown. Calculate: emf of… 2026 · 3 marks · Numerical
Two cells of same emf E, but different internal resistance $r_1$ and $r_2$ are connected to an external resistance R as shown in… 2026 · 2 marks · Numerical
Answer the following questions: Many identical cells, each of an emf of 1.5V and an internal resistance of $2\Omega$, are… 2026 · 2 marks · Short answer
Current I flowing through a metallic wire is gradually increased. Show graphically how heating power (P) developed in it varies… 2026 · 1 mark · Drawing
Using Kirchhoff’s laws of electric network, calculate the current flowing through the $5\Omega$ resistor shown in Figure 3 below. 2026 · 3 marks · Numerical
The current (I)-voltage (V) graphs for a conductor are given at two different temperatures $T_1$ and $T_2$. (Analysis) At which… 2026 · 2 marks · Short answer
Draw a labelled circuit diagram of a potentiometer used to compare emfs of two given cells X and Y. (Procedure and formula are… 2026 · 2 marks · Drawing
A fish called an electric eel can generate a voltage up to 800V. If it can supply a current of 5mA, the maximum power it can… 2026 · 1 mark · MCQ
Ramesh performed an experiment to determine an unknown resistance R using the circuit shown in Figure 6 below. X is a resistance… 2026 · 2 marks · Short answer
Figure 2 below shows a circuit which is used to measure resistance of a piece of metallic wire X. Write the mathematical formula… 2026 · 2 marks · Short answer
When a battery is connected between the terminals P and Q, as shown in Figure 1 below, it is found that no current flows through… 2025 · 1 mark · MCQ
In a potentiometer, a cell is balanced against $110\text{ cm}$ when the circuit is open. A cell is balanced at $100\text{ cm}$… 2025 · 2 marks · Numerical
Two cells of electromotive forces (e.m.f.s.) approximately 5 V and 10 V are to be accurately compared using a potentiometer of… 2025 · 2 marks · Short answer
Two cells of emf $13\text{ V}$ and $12\text{ V}$ and negligible internal resistance are connected in the circuit shown in Figure… 2025 · 3 marks · Numerical
A current I is flowing through a wire of non-uniform cross-section as shown in the figure. Which of the following options gives… 2025 · 1 mark · MCQ
For the given electrical circuit, calculate the current through each branch using Kirchhoff's laws. 2025 · 3 marks · Numerical
The potentiometer has a driver cell D of emf $6\text{ V}$ and an internal resistance of $2\ \Omega$, as shown in Figure 7 below… 2025 · 3 marks · Numerical
Harry sets up a circuit as shown in Figure 7 below. He measures potential difference ‘$V$’ across the variable resistor R with an… 2025 · 3 marks · Short answer
In Figure 2 below, the current-voltage graphs for a conductor are given at two different temperatures $T_1$ and $T_2$. At which… 2025 · 2 marks · Short answer
Three cells having emfs $3\text{ V}$, $1\text{ V}$ and $4\text{ V}$ are connected as shown in Figure 1 below. Their internal… 2025 · 1 mark · MCQ
In Figure 4 shown below, internal resistance of the battery is negligible. Calculate the Ammeter reading, assuming its resistance… 2025 · 2 marks · Numerical
Study the two circuits shown in Figure 6 below. The cells in the two circuits are identical to each other. The resistance of the… 2025 · 3 marks · Numerical
The graph below shows the variation of current density ($J$) with electric field ($E$) applied to two different metallic wires A… 2025 · 3 marks · Short answer
Sheetal had 6 identical cells, each of electromotive force (emf) 4 V and internal resistance 'r'. She connected them to an… 2025 · 1 mark · MCQ
Two resistors, $R_1 = 1\ \Omega$ and $R_2 = 2\ \Omega$ are connected in parallel. If the power developed in the resistor $R_1$ is… 2025 · 2 marks · Numerical
In a Wheatstone bridge, three resistances P, Q, and R are connected in the three arms, and the fourth arm is formed by two… 2025 · 2 marks · Derivation
The student sets up an experiment in the lab to determine the internal resistance of a cell by graphical method. The setup of the… 2025 · 2 marks · Short answer
The drift velocity of electrons in a conductor connected to a battery is given by $v_d = -eE\tau/m$. Here, $e$ is the charge of… 2025 · 3 marks · Short answer
In a potentiometer experiment, a cell of emf $1.25\text{ V}$ gives a balance point at $35\text{ cm}$ mark of the wire. If this… 2025 · 2 marks · Numerical
Figure 6 below shows an electric circuit. Apply Kirchhoff’s laws to calculate: current ‘$I$’ flowing through the $2\ \Omega$… 2025 · 2 marks · Numerical
What is the effect of increasing the temperature of a piece of metal on relaxation time of free electrons? 2025 · 1 mark · Short answer
Figure 4 below shows a part of an electric circuit. Apply Kirchhoff’s junction rule to the junction A to find current flowing… 2025 · 2 marks · Short answer
Using a cell of electromotive force (e.m.f.) $\varepsilon$ and internal resistance 'r', a student designs an electrical circuit… 2025 · 1 mark · Short answer
Each of the batteries connected in the circuit is of electromotive force (emf) 4V and internal resistance of 1 ohm. What is the… 2025 · 1 mark · MCQ
Current I flowing through a metallic wire is gradually increased. Show graphically how heating power (P) developed in it varies… 2025 · 1 mark · Drawing
Figures 4 and 5 represent the combination of two identical cells having negligible internal resistance. In which of the two… 2025 · 2 marks · Short answer
The current passing through a wire varies with time as provided below. The charge passing through the wire from 0s to 5s is: 2025 · 1 mark · MCQ
Figure 1 below shows a circuit containing an ammeter A, a galvanometer G and a plug key K. When the key is closed: 2025 · 1 mark · MCQ
Figure 2 below shows two batteries $E_1$ and $E_2$ having emfs of $18\text{ V}$ and $10\text{ V}$ and internal resistances of… 2024 · 3 marks · Numerical
A metre bridge is balanced with a known resistance (R) in the left hand gap and an unknown resistance (S) in the right hand gap… 2024 · 1 mark · MCQ
If potential difference between the two ends of a metallic wire is doubled, drift speed of free electrons in the wire: 2024 · 1 mark · MCQ
Three bulbs $B_1(230\text{ V}, 40\text{ W})$, $B_2(230\text{ V}, 60\text{ W})$ and $B_3(230\text{ V}, 100\text{ W})$ are… 2024 · 1 mark · Short answer
Three identical cells each of emf ‘e’ are connected in parallel to form a battery. What is the emf of the battery? 2024 · 1 mark · Short answer
Figure 3 below shows a potentiometer circuit in which the driver cell D has an emf of $6\text{ V}$ and internal resistance of… 2024 · 3 marks · Numerical
In the circuit shown in Figure 3 below, $E_1$ and $E_2$ are batteries having emfs of $25\text{ V}$ and $26\text{ V}$. They have… 2023 · 3 marks · Numerical
Eight identical cells, each of emf $2\text{ V}$ and internal resistance $3\,\Omega$, are connected in series to form a row. Six… 2023 · 3 marks · Numerical
In case of metals, what is the relation between current density ($J$), electrical conductivity ($\sigma$) and electric field… 2023 · 1 mark · Short answer
In a meter bridge circuit, resistance in the left gap is $4\\,\Omega$ and an unknown resistance $R$ is in the right-hand gap as… 2023 · 3 marks · Numerical
Write balancing condition of a Wheatstone bridge. Current ‘$I$’ flowing through a metallic wire is related to drift speed $v_d$… 2023 · 2 marks · Short answer
An electric current ($I$) flowing through a metallic wire is gradually increased. The graph of heating power ($P$) developed in… 2023 · 1 mark · MCQ
Name the conservation principle implied in Kirchhoff’s Junction law for electric circuits. 2023 · 1 mark · Short answer
If $R_1$ and $R_2$ are filament resistances of a $100\text{ W}$ bulb and a $50\text{ W}$ bulb respectively, designed to operate… 2023 · 1 mark · MCQ
With reference to free electron theory of conductors, define: Drift velocity State any one use of a potentiometer. 2023 · 2 marks · Short answer
A circuit is used to determine the internal resistance and the emf of a cell. It consists of the cell, a variable resistor, an… 2023 · 3 marks · Numerical
The circuit shown in figure 9 below is used to compare the e.m.f. of two cells $E_1$ and $E_2$ where $E_2 > E_1$. The null point… 2022 · 1 mark · MCQ
The current in the circuit shown in figure 7 below, will be: 2022 · 1 mark · MCQ
Four identical cells each having an e.m.f. of 4V are connected in parallel. What will be the e.m.f. of this combination? 2022 · 1 mark · MCQ
The potential gradient along the length of a uniform wire is 20 volt/metre. B and C are the two points at 40cm and 70cm point on… 2022 · 1 mark · MCQ
A torch bulb rated as 4.5 W, 1.5 V is connected as shown in figure 12 given below. What should be the e.m.f. of the cell required… 2022 · 2 marks · Short answer
The drift velocity of a current carrying conductor is v. What will be the drift velocity if the current flowing through the wire… 2022 · 1 mark · MCQ
The resistance of a wire is $10\ \Omega$. It is stretched so that its length becomes four times. What will be the new resistance… 2022 · 1 mark · MCQ
n identical cells each of e.m.f. E and internal resistance r are connected in parallel. An external resistance R is connected in… 2022 · 1 mark · MCQ
The figure 8 given below shows currents in a part of an electric circuit. The current i is: 2022 · 1 mark · MCQ
A cell of e.m.f. E is connected to an external resistance R. The potential difference across cell is V. The internal resistance… 2022 · 1 mark · MCQ
The specific resistance of manganin is $50 \times 10^{-8}\ \Omega\text{ m}$. The resistance of a cube of length 50m will be: The… 2022 · 2 marks · Short answer
A 2 volt battery, a $15\ \Omega$ resistor and a potentiometer of 100 cm length, all are connected in series. If the resistance of… 2022 · 1 mark · MCQ
In an experiment of meter bridge, a null point is obtained at the centre of the bridge wire. When a resistance of 5 is connected… 2022 · 1 mark · MCQ
Two bulbs B1 and B2 are connected in series with an source of emf 250V as shown in the figure 15 below. The labels on the bulbs… 2022 · 3 marks · Short answer
If m, e, $\tau$ and n respectively represent the mass, charge, average relaxation time and density of the electron, then what… 2022 · 1 mark · MCQ
Given below is a neat, labelled diagram to obtain balancing condition of Wheatstone bridge. Why is the key ‘K’ pressed before the… 2022 · 3 marks · Short answer
A uniform copper wire having a cross sectional area of $1\text{ mm}^2$ carries a current of $5\text{ A}$. Calculate the drift… 2020 · 2 marks · Numerical
An electric bulb is rated as $250\text{ V}$, $750\text{ W}$. Calculate the: Electric current flowing through it, when it is… 2020 · 2 marks · Short answer
A potentiometer circuit is shown in Figure 3 below. AB is a uniform metallic wire having length of $2\text{ m}$ and resistance of… 2020 · 3 marks · Short answer
$E_1$ and $E_2$ are two batteries having emfs of $3\text{V}$ and $4\text{V}$ and internal resistances of $2\ \Omega$ and… 2020 · 3 marks · Numerical
A metallic wire having a resistance of $20\ \Omega$ is bent in order to form a complete circle. Calculate the resistance between… 2020 · 1 mark · Numerical
Calculate the net emf across A and B shown in Figure 1 below: 2019 · 1 mark · Numerical
Draw a labelled circuit diagram of a potentiometer to measure the internal resistance ‘r’ of a cell. Write the working formula… 2019 · 3 marks · Drawing
Obtain the balancing condition for the Wheatstone bridge arrangement as shown in Figure 4 below: 2019 · 3 marks · Derivation
In a potentiometer experiment, the balancing length with a resistance of $2\\ \Omega$ is found to be $100\text{ cm}$, while that… 2019 · 2 marks · Numerical
Define drift velocity and relaxation time, with reference to the free electron theory of conductors. 2018 · 2 marks · Short answer
An electric bulb is marked $200\text{V}, 100\text{W}$. Calculate electrical resistance of its filament. If five such bulbs are… 2018 · 3 marks · Numerical
How will the sensitivity of a potentiometer change with increase in current flowing through its wire? 2018 · 1 mark · Short answer
In a potentiometer experiment, balancing length is found to be $120\text{ cm}$ for a cell $E_1$ of emf $2\text{V}$. What will be… 2018 · 1 mark · Numerical
$\varepsilon_1$ and $\varepsilon_2$ are two batteries having emf of $34\text{V}$ and $10\text{V}$ respectively and internal… 2018 · 3 marks · Numerical
The order of coloured rings in a carbon resistor is red, yellow, blue and silver. The resistance of the carbon resistor is: 2018 · 1 mark · MCQ
Using Kirchhoff’s laws of electrical networks, calculate the currents $I_1$, $I_2$ and $I_3$ in the circuit shown below (Figure… 2018 · 3 marks · Numerical
Ohm’s law in vector form is: 2018 · 1 mark · MCQ
Define current density. Write an expression which connects current density with drift speed. 2018 · 2 marks · Short answer

Current Electricity - ISC Class 12 Physics Questions with Answers

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