Case study on electric circuits

This type of question, asked 4 times: 2022, 2023, 2024, 2025. All 6 questions below, oldest first.

Try each one first, then open its answer.

Question 1 (case study, 4 parts)
2022
Study the following electric circuit in which the resistors are arranged in three arms A, B and C :
14 (a) $Find the equivalent resistance of arm A.$
14 (b) $Calculate the equivalent resistance of the parallel combination of the arms B and C.$
14 (c) (i) $Determine the current that flows through the ammeter.$
14 (c) (ii) $Determine the current that flows in the ammeter when the arm B is withdrawn from the circuit.$
Question 2 (case study, 4 parts)
2023
Consider the following electrical circuit diagram in which nine identical resistors of $3\,\Omega$ each are connected as shown. If the reading of the ammeter $\mathrm{A_1}$ is 1 ampere, answer the following questions :
39 (a) $\mathrm{A_1}$
39 (b) $\mathrm{A_2}$
39 (c) $\mathrm{V_1}$
39 (c) OR $Find the total resistance of the circuit.$
Question 3 (case study, 4 parts)
2024
Study the following circuit :
39 (a) $Find the value of total resistance between the points A and B.$
39 (b) $Find the resistance between the points B and C.$
39 (c) (i) $Calculate the current drawn from the battery, when the key is closed.$
39 (c) (ii) $16\,\Omega$
Question 4 (case study, 4 parts)
2024
In a domestic circuit five LED bulbs are arranged as shown. The source voltage is 220 V and the power rating of each bulb is marked in the circuit diagram. Based on the following circuit diagram, answer the following questions :
39 (a) $\mathrm{K_1}$
39 (b) $Find the current drawn by the bulb B when it glows.$
39 (c) $Calculate (i) the resistance of bulb B, and (ii) total resistance of the combination of four bulbs B, C, D and E.$
39 (c) OR $\mathrm{K_1}$
Question 5 (case study, 4 parts)
2025
Study the circuit shown in which two resistors X and Y of resistances $3\,\Omega$ and $6\,\Omega$ respectively are joined in series with a battery of 2 V.
39 (I) $Draw a circuit diagram showing the above two resistors X and Y joined in parallel with same battery and same ammeter and voltmeter.$
39 (II) $In which combination of resistors will the (i) potential difference across X and Y and (ii) current through X and Y, be the same ?$
39 (III) (a) $Find the current drawn from the battery by the series combination of the two resistors (X and Y).$
39 (III) (b) $Determine the equivalent resistance of the parallel combination of the two resistors (X and Y).$
Question 6 (case study, 4 parts)
2025
As shown in the diagram, an electric circuit consisting of an ammeter, a voltmeter, 4 cells of $1{\cdot}5$ V each, a plug key with a gap XY was set up. Voltmeter and ammeter readings were recorded in the observation table for four arrangements as given below : Arrangement No. 1 – only resistor $\mathrm{R_1}$ in gap XY Arrangement No. 2 – only resistor $\mathrm{R_2}$ in gap XY Arrangement No. 3 – Resistors $\mathrm{R_1}$ and $\mathrm{R_2}$ in series in gap XY Arrangement No. 4 – Resistors $\mathrm{R_1}$ and $\mathrm{R_2}$ in parallel in gap XY Based on the observations, four V – I graphs A, B, C and D as shown in figure were drawn. Study these graphs.
39 (a) $\mathrm{R_1}$
39 (b) $\mathrm{R_1}$
39 (c) (i) $10\,\Omega$
39 (c) (ii) $0{\cdot}1\,\Omega$