Ohm's Law for a Closed Circuit questions

An electric source has an emf of 8 V and an internal resistance r. The potential difference between its terminals while a current flows in its circuit is ..........

1. A equal to 8 V
2. B less than 8 V
3. C greater than 8 V
4. D impossible to determine without knowing r

In the opposite circuit, when the variable resistance (S) is increased, the voltmeter reading ..........

1. A increases
2. B decreases until it becomes zero
3. C stays the same
4. D decreases but does not become zero

When a battery of emf 6 V is connected to a 10 Ω resistance, a current of 0.5 A flows. The internal resistance of the battery is ..........

1. A 0.5 Ω
2. B 1 Ω
3. C 1.5 Ω
4. D 2 Ω

Three resistances 3 Ω, 6 Ω and 4 Ω are connected in series to a battery of emf 30 V and internal resistance 2 Ω, so:
The total resistance of the circuit is ..........

1. A 11 Ω
2. B 13 Ω
3. C 15 Ω
4. D 19 Ω

Three resistances 3 Ω, 6 Ω and 4 Ω are connected in series to a battery of emf 30 V and internal resistance 2 Ω, so:
The current flowing in the circuit is ..........

1. A 0.5 A
2. B 1 A
3. C 1.5 A
4. D 2 A

Three resistances 3 Ω, 6 Ω and 4 Ω are connected in series to a battery of emf 30 V and internal resistance 2 Ω, so:
The potential difference across the 6 Ω resistance is ..........

1. A 6 V
2. B 8 V
3. C 12 V
4. D 18 V

In the circuit shown, when $R_V$ is decreased, the reading of the voltmeter (V) ..........

1. A increases
2. B decreases until it becomes zero
3. C stays constant
4. D decreases but does not become zero

When the external circuit of a battery is closed, the current flowing through it is inversely proportional to ..........

1. A the emf of the battery
2. B the internal resistance of the battery
3. C the external equivalent resistance of the circuit
4. D the total resistance of the circuit

In the circuit shown in the figure, if the filament of one of the two lamps burns out, the voltmeter reading ..........

1. A increases
2. B decreases but is not zero
3. C does not change
4. D becomes zero

In the circuit shown, when the switch S is closed, the readings of the voltmeter and the ammeter respectively ..........

1. A decrease, decrease
2. B decrease, increase
3. C increase, decrease
4. D increase, increase

The opposite graph represents the relation between the potential difference between the terminals of a battery (V) and the current flowing through it (I), so:
The internal resistance of the battery is ..........

1. A 1 Ω
2. B 2 Ω
3. C 0.45 Ω
4. D 0.9 Ω

The opposite graph represents the relation between the potential difference between the terminals of a battery (V) and the current flowing through it (I), so:
The emf of the battery is ..........

1. A 7 V
2. B 7.5 V
3. C 8 V
4. D 9 V

The opposite graph represents the relation between the potential difference between the terminals of two cells (x) and (y) and the current flowing in the circuit of each. The ratio between their internal resistances $\left(\frac{r_x}{r_y}\right)$ is ..........

1. A $\dfrac{1}{2}$
2. B $\dfrac{1}{3}$
3. C $\dfrac{\sqrt{3}}{2}$
4. D $\sqrt{\dfrac{3}{2}}$

Figure (1) is a graph of the relation between the voltmeter reading (V) and the ammeter reading (A) when the resistance (R) is changed in the circuit shown in figure (2).
If the internal resistance of the battery is 0.25 Ω, which of the following represents two possible values for the points (x) and (y) shown on the graph?

1. A x = 8 V, y = 8 A
2. B x = 8 V, y = 2 A
3. C x = 2 V, y = 8 A
4. D x = 2 V, y = 4 A

In the circuit shown in the figure, if the ammeter reads 1 A, the voltmeter reads ..........

1. A 3 V
2. B 6 V
3. C 7 V
4. D 9 V

A metal wire of length 30 m, cross-sectional area 0.3 cm² and resistivity $5 \times 10^{-7}$ Ω.m is connected in series with a resistance of 8.5 Ω and a battery of emf 18 V and internal resistance 1 Ω. The current flowing in the circuit is ..........

1. A 0.9 A
2. B 1.8 A
3. C 3.6 A
4. D 4.2 A

A battery of emf 6 V and internal resistance 1 Ω, an ammeter of negligible resistance, a fixed resistance R and a rheostat are connected in series. When the slider is at the start of the rheostat, a current of 0.6 A flows in the circuit, and when the slider is at the end of the rheostat, a current of 0.1 A flows, so:
The resistance R is ..........

1. A 3 Ω
2. B 6 Ω
3. C 9 Ω
4. D 12 Ω

A battery of emf 6 V and internal resistance 1 Ω, an ammeter of negligible resistance, a fixed resistance R and a rheostat are connected in series. When the slider is at the start of the rheostat, a current of 0.6 A flows in the circuit, and when the slider is at the end of the rheostat, a current of 0.1 A flows, so:
The maximum resistance of the rheostat is ..........

1. A 15 Ω
2. B 27 Ω
3. C 38 Ω
4. D 50 Ω

Two resistances $R_1 = 6$ Ω and $R_2 = 4$ Ω are connected in parallel between the terminals of an electric source of emf 6 V and internal resistance 0.1 Ω, so:
The current flowing in the circuit is ..........

1. A 1.3 A
2. B 2.4 A
3. C 3.6 A
4. D 4 A

Two resistances $R_1 = 6$ Ω and $R_2 = 4$ Ω are connected in parallel between the terminals of an electric source of emf 6 V and internal resistance 0.1 Ω, so:
The electric power consumed in the circuit (inside and outside the source) is ..........

1. A 14.4 W
2. B 15 W
3. C 18.3 W
4. D 21.9 W

Two resistances $R_1 = 6$ Ω and $R_2 = 4$ Ω are connected in parallel between the terminals of an electric source of emf 6 V and internal resistance 0.1 Ω, so:
The electric power consumed in $R_1$ is ..........

1. A 12.2 W
2. B 9.3 W
3. C 6.1 W
4. D 5.53 W

In the opposite circuit, if the reading of ammeter $A_1$ is 1 A, the reading of ammeter $A_2$ is 2 A and the internal resistance of the battery (r) is 1 Ω, so:
The value of the resistance R is ..........

1. A 2 Ω
2. B 4.5 Ω
3. C 9 Ω
4. D 13 Ω

In the opposite circuit, if the reading of ammeter $A_1$ is 1 A, the reading of ammeter $A_2$ is 2 A and the internal resistance of the battery (r) is 1 Ω, so:
The emf of the battery is ..........

1. A 14 V
2. B 12 V
3. C 9 V
4. D 8 V

In the circuit shown in the figure, if the voltmeter reads 6 V, the resistance R is ..........

1. A 2 Ω
2. B 3 Ω
3. C 4.8 Ω
4. D 6 Ω

In the circuit shown, the potential difference between b and c is ..........

1. A 5 V
2. B 10 V
3. C 15 V
4. D 20 V

In the opposite circuit, if the voltmeter reads 8 V, the emf of the battery $(V_B)$ is ..........

1. A 8 V
2. B 10 V
3. C 12 V
4. D 14 V

In the opposite figure, if the current flowing in the 6 Ω resistance is 1 A, so:
The reading of the ammeter (A) is ..........

1. A 3.4 A
2. B 3 A
3. C 2.8 A
4. D 2 A

In the opposite figure, if the current flowing in the 6 Ω resistance is 1 A, so:
The reading of the voltmeter (V) is ..........

1. A 1 V
2. B 3 V
3. C 6 V
4. D 9 V

In the opposite figure, if the current flowing in the 6 Ω resistance is 1 A, so:
The emf of the battery is ..........

1. A 11 V
2. B 13 V
3. C 15 V
4. D 19 V

Three resistances 8 Ω, 6 Ω and 16 Ω are connected together in a certain way, then the group is connected to a current source of internal resistance 1.2 Ω. When the circuit is closed, the p.d. across the 8 Ω resistance is 2 V, across the 6 Ω resistance is 6 V and across the 16 Ω resistance is 4 V. The emf of the source is ..........

1. A 6 V
2. B 7.5 V
3. C 9 V
4. D 12 V

In the opposite circuit, the voltmeter reading is ..........

1. A $V_B - 2Ir$
2. B $V_B + Ir$
3. C $\dfrac{IR}{2}$
4. D $2IR$

In the opposite circuit, if the internal resistance of the battery is $\frac{1}{4}$R, the voltmeter reading is ..........

1. A $\dfrac{2}{3} V_B$
2. B $\dfrac{5}{4} V_B$
3. C $\dfrac{1}{5} V_B$
4. D $\dfrac{4}{5} V_B$

In the circuit shown in the figure, when the switch K is closed, the readings of the ammeter (A) and the voltmeter (V) ..........

1. A ammeter reading increases, voltmeter reading decreases
2. B ammeter reading decreases, voltmeter reading increases
3. C ammeter reading increases, voltmeter reading increases
4. D ammeter reading decreases, voltmeter reading decreases

What happens to the readings of the ammeter and the voltmeter respectively when the variable resistance S in the opposite circuit is increased?

1. A increase, increase
2. B increase, decrease
3. C decrease, increase
4. D decrease, decrease

The opposite figure shows a closed circuit. When the variable resistance (S) is increased, the readings of the two voltmeters $V_1$ and $V_2$ respectively ..........

1. A increase, increase
2. B decrease, decrease
3. C increase, decrease
4. D decrease, increase

In the circuit shown, if the value of the variable resistance (S) is decreased, which of the following ratios decreases?

1. A $\dfrac{V_1}{V_B}$
2. B $\dfrac{V_2}{V_1}$
3. C $\dfrac{V_B}{V_2}$
4. D $\dfrac{V_1}{V_2}$

You have a group of resistances, each of 8 Ω. How many of them are needed, and how should they be connected between the points X and Y, so that a current of 2 A flows in the circuit?

1. A two resistances, in series
2. B three resistances, in series
3. C four resistances, in parallel
4. D six resistances, in parallel

In the circuit shown in the figure, if the current flowing in the circuit when the switch K is closed is 0.5 A greater than when it is open, the emf of the battery is ..........

1. A 8.2 V
2. B 9.4 V
3. C 10.3 V
4. D 11.7 V

The opposite figure shows four resistances connected in the shape of a square ABCD, so:
The two points to which a battery of internal resistance 1 Ω must be connected so that a current of 0.25 A flows in all the resistances are ..........

1. A A, B
2. B B, D
3. C C, D
4. D A, C

The opposite figure shows four resistances connected in the shape of a square ABCD, so:
If a battery of internal resistance 1 Ω is connected between the two points that make the current in all the resistances 0.25 A, the emf of this battery is ..........

1. A 13 V
2. B 26 V
3. C 35 V
4. D 40 V

The opposite figure shows a circuit consisting of a battery $V_B$ of internal resistance 1 Ω connected to four resistances $R_1$, $R_2$, $R_3$ and $R_4$. A current of 0.3 A flows in $R_1$, 0.3 A in $R_2$, 0.4 A in $R_3$ and 0.2 A in $R_4$, so:
The emf $V_B$ of the source is ..........

1. A 5.4 V
2. B 6.9 V
3. C 7.13 V
4. D 9.51 V

The opposite figure shows a circuit consisting of a battery $V_B$ of internal resistance 1 Ω connected to four resistances $R_1$, $R_2$, $R_3$ and $R_4$. A current of 0.3 A flows in $R_1$, 0.3 A in $R_2$, 0.4 A in $R_3$ and 0.2 A in $R_4$, so:
The total resistance of the circuit is ..........

1. A 30 Ω
2. B 14 Ω
3. C 7.67 Ω
4. D 13.34 Ω

In the circuit shown in the figure, the readings of the two voltmeters $V_1$ and $V_2$ are ..........

1. A $V_1$ = 2.25 V, $V_2$ = 5.5 V
2. B $V_1$ = 4.8 V, $V_2$ = 4.8 V
3. C $V_1$ = 2.25 V, $V_2$ = 2.25 V
4. D $V_1$ = 4.8 V, $V_2$ = 2.4 V

A resistance (R) is connected to a battery of internal resistance (r) and a switch, as in the opposite circuit. If the voltmeter reads $(V_o)$ when the switch is open, and its reading becomes $0.8 V_o$ when the switch is closed, the ratio $\left(\frac{R}{r}\right)$ is ..........

1. A 1
2. B 2
3. C 4
4. D 8

In the opposite circuit, when the switch K is open the voltmeter reads 12 V, and when the switch K is closed the voltmeter reads 9 V and the ammeter reads 1.5 A, so:
The internal resistance of the battery is ..........

1. A 0.5 Ω
2. B 1 Ω
3. C 1.5 Ω
4. D 2 Ω

In the opposite circuit, when the switch K is open the voltmeter reads 12 V, and when the switch K is closed the voltmeter reads 9 V and the ammeter reads 1.5 A, so:
The value of the resistance R is ..........

1. A 2 Ω
2. B 4 Ω
3. C 6 Ω
4. D 8 Ω

In the circuit shown in the figure, the internal resistance of the battery is 2 Ω. The voltmeter reads 12 V when the switch K is open, and its reading becomes 10 V when the switch K is closed, so:
The current flowing in the circuit when the switch K is closed is ..........

1. A 4 A
2. B 3 A
3. C 2 A
4. D 1 A

In the circuit shown in the figure, the internal resistance of the battery is 2 Ω. The voltmeter reads 12 V when the switch K is open, and its reading becomes 10 V when the switch K is closed, so:
The value of the resistance R is ..........

1. A 5 Ω
2. B 10 Ω
3. C 15 Ω
4. D 20 Ω

In the opposite circuit, a voltmeter is connected across a battery of emf $(V_B)$ and internal resistance (r). The voltmeter reads zero when .......... is closed.

1. A the switch $K_1$ only
2. B the two switches $K_1$ and $K_2$ only
3. C the two switches $K_1$ and $K_3$ only
4. D all three switches $K_1$, $K_2$ and $K_3$

In the opposite circuit, if the pointer of the ammeter $(A_2)$ stays at zero, the reading of the ammeter $(A_1)$ is ..........

1. A 3.5 A
2. B 2.5 A
3. C 2 A
4. D 1.5 A

An electric source is connected to a uniform conductor (x) through a slider, as in the opposite circuit. What happens to the voltmeter reading (V) when the length of the part of the conductor that carries the current is increased?

1. A increases
2. B decreases
3. C does not change
4. D cannot be determined

In the circuit shown, two uniform conductors (x) and (y) of the same metal, of lengths (ℓ) and (2ℓ) and cross-section diameters (d) and $\left(\frac{d}{2}\right)$ respectively, can be connected through a two-way switch to a battery of internal resistance (r). The following table records the voltmeter reading as the switch contact point is changed:
The switch is not connected to either point (a) or (b): $V_1$
The switch is connected to point (a): $V_2$
The switch is connected to point (b): $V_3$
The correct order of the three voltmeter readings is ..........

1. A $V_1 = V_2 = V_3$
2. B $V_1 > V_2 > V_3$
3. C $V_1 > V_3 > V_2$
4. D $V_3 > V_2 > V_1$

In the opposite circuit, the emf of the battery is ..........

1. A 25 V
2. B 30 V
3. C 35 V
4. D 45 V

Three identical resistances are connected to a battery of internal resistance (r) in four different ways, as shown in the following circuits. In which of these circuits is the voltmeter reading the greatest?

1. A A
2. B B
3. C C
4. D D

What change should be made in the opposite circuit to increase the current flowing in the lamp?

1. A Adding a resistance in parallel with the resistance in the circuit
2. B Adding a resistance in series with the resistance in the circuit
3. C Removing one of the two cells
4. D Moving the lamp to point P

The opposite figure represents a closed circuit. Which of the following components represents the element X that makes the voltmeter pointer deflect to 4 V?

1. A A
2. B B
3. C C
4. D D

In the circuit in front of you, the voltmeter reading is ..........

1. A 7.64 V
2. B 2.36 V
3. C 2 V
4. D 1.64 V

In the opposite circuit, if we remove one of the two cells of the battery and connect another resistance in series with the resistance R, the voltmeter reading ..........

1. A increases
2. B decreases
3. C stays the same
4. D cannot be determined

In the circuit shown in the figure, if the internal resistance of each cell is 2 Ω, so:
The total external resistance of the circuit is ..........

1. A 5 Ω
2. B 10 Ω
3. C 20 Ω
4. D 25 Ω

In the circuit shown in the figure, if the internal resistance of each cell is 2 Ω, so:
The total current flowing in the circuit is ..........

1. A 0.25 A
2. B 0.5 A
3. C 0.75 A
4. D 1 A

The opposite figure shows four identical cells, each of emf 12 V, connected to an electric lamp. If the current flowing in the circuit is 0.5 A and the power consumed in the lamp is 23 W, the internal resistance of each cell is ..........

1. A 0.5 Ω
2. B 1 Ω
3. C 1.5 Ω
4. D 2 Ω

In the circuit shown, when the switch $K_1$ is opened and the switch $K_2$ is closed, which of the following choices shows what happens to both the direction of the current in the resistance R and the ammeter reading?

1. A the current direction stays the same, the ammeter reading increases
2. B the current direction is reversed, the ammeter reading decreases
3. C the current direction stays the same, the ammeter reading decreases
4. D the current direction is reversed, the ammeter reading increases

In the opposite circuit, the reading of voltmeter $V_1$ is 4 V while the switch K is open. Given that $(V_B)_2 > (V_B)_1$, the readings of the two voltmeters $V_1$ and $V_2$ after closing the switch K are ..........

1. A $V_1$ = 3 V, $V_2$ = 11.5 V
2. B $V_1$ = 3 V, $V_2$ = 8 V
3. C $V_1$ = 4.5 V, $V_2$ = 11.5 V
4. D $V_1$ = 4.5 V, $V_2$ = 8 V

From the opposite circuit:
The current flowing in the circuit is ..........

1. A $\dfrac{2}{3}$ A
2. B $\dfrac{3}{2}$ A
3. C $\dfrac{1}{2}$ A
4. D $\dfrac{1}{4}$ A

From the opposite circuit:
The potential difference between the points a and b is ..........

1. A $\dfrac{7}{2}$ V
2. B $\dfrac{5}{3}$ V
3. C $\dfrac{4}{9}$ V
4. D $\dfrac{2}{3}$ V

From the opposite circuit:
The potential difference between the points b and c is ..........

1. A 0.4 V
2. B 2.25 V
3. C 0.625 V
4. D 1.6 V

In the opposite circuit, the voltmeter reading is ..........

1. A 20 V
2. B 10 V
3. C 5 V
4. D 0

A battery of emf 8 V and internal resistance 0.4 Ω is charged by a source of internal resistance 0.4 Ω, and a current of 2.5 A flows in the circuit. Neglecting the resistance of the connecting wires, the emf of the source used to charge the battery is ..........

1. A 12 V
2. B 11 V
3. C 10 V
4. D 6 V

In the circuit shown, if the power consumed in the 4 Ω resistance is 16 W, the value of r is ..........

1. A 0.25 Ω
2. B 0.5 Ω
3. C 1 Ω
4. D 2 Ω

Each of the following circuits consists of a voltmeter, an ohmic resistance (R) and two batteries, each with an internal resistance (r). In which of these circuits is the voltmeter reading greater than the emf $(V_B)$?

1. A A
2. B B
3. C C
4. D D

In the opposite circuit, the ratio $\frac{V_2}{V_1}$ is ..........

1. A $\dfrac{5}{11}$
2. B $\dfrac{2}{3}$
3. C $\dfrac{7}{11}$
4. D $\dfrac{1}{1}$

From the circuit shown in the figure:
The reading of ammeter $A_1$ is ..........

1. A 2 A
2. B 5 A
3. C 7 A
4. D 10 A

From the circuit shown in the figure:
The reading of ammeter $A_2$ is ..........

1. A 0.5 A
2. B 1 A
3. C 1.5 A
4. D 2 A

In the opposite circuit, if the readings of the two voltmeters $(V_1)$ and $(V_2)$ are 16 V and 6 V respectively, the value of the resistance (R) and the emf $(V_B)_1$ respectively are ..........

1. A R = 3 Ω, $(V_B)_1$ = 16 V
2. B R = 4 Ω, $(V_B)_1$ = 10 V
3. C R = 3 Ω, $(V_B)_1$ = 18 V
4. D R = 4 Ω, $(V_B)_1$ = 18 V

Each of the following figures represents a circuit of three identical resistances connected to three identical cells of negligible internal resistance, in three different ways.
The ratio between the currents $I_1 : I_2 : I_3$ is ..........

1. A $9 : 1 : 3$
2. B $2 : 3 : 1$
3. C $3 : 6 : 2$
4. D $1 : 4 : 9$

A cell is connected to a resistance of 1.9 Ω and a current of 0.5 A flows. When this resistance is replaced by another of 10.6 Ω, the current drops to 0.125 A. The emf of the cell is ..........

1. A 5.3 V
2. B 3.31 V
3. C 2.7 V
4. D 1.45 V

A cell is connected to a resistance R and the current flowing in it is I. When another resistance $\frac{R}{2}$ is connected in parallel with the first one, the current in the circuit doubles. The internal resistance of the cell is ..........

1. A 3R
2. B $\dfrac{R}{3}$
3. C 6R
4. D $\dfrac{R}{6}$

An ohmic resistance R is connected to two different batteries, each on its own, as shown in the two opposite circuits. If the two voltmeter readings are equal, each 3 V, the ratio between the internal resistances of the two batteries $\left(\frac{r_1}{r_2}\right)$ is ..........

1. A $\dfrac{2}{3}$
2. B $\dfrac{3}{2}$
3. C $\dfrac{1}{3}$
4. D 3

Two identical wires made of the same material, each 50 cm long with a cross-sectional area of 2 mm², are connected in series in a circuit with a cell of internal resistance 0.5 Ω, and the current in the circuit is 2 A. When the same two wires are connected in parallel to the same cell, the total current in the circuit is 6 A, so:
The emf of the cell used is ..........

1. A 3 V
2. B 6 V
3. C 9 V
4. D 12 V

Two identical wires made of the same material, each 50 cm long with a cross-sectional area of 2 mm², are connected in series in a circuit with a cell of internal resistance 0.5 Ω, and the current in the circuit is 2 A. When the same two wires are connected in parallel to the same cell, the total current in the circuit is 6 A, so:
The electrical conductivity of the wire material is ..........

1. A $125 \times 10^{3}$ $\Omega^{-1}.m^{-1}$
2. B $250 \times 10^{4}$ $\Omega^{-1}.m^{-1}$
3. C $396 \times 10^{6}$ $\Omega^{-1}.m^{-1}$
4. D $431 \times 10^{8}$ $\Omega^{-1}.m^{-1}$

A battery of emf 12 V is connected to two identical lamps connected in parallel. The p.d. between the terminals of the battery becomes 10.8 V and the power consumed in each lamp is 12 W. The internal resistance of the battery is ..........

1. A 0.25 Ω
2. B 0.54 Ω
3. C 0.72 Ω
4. D 1 Ω

From the opposite circuit:
The current flowing through the 12 V battery is ..........

1. A $\dfrac{3}{5}$ A
2. B $\dfrac{1}{3}$ A
3. C $\dfrac{4}{9}$ A
4. D $\dfrac{7}{8}$ A

From the opposite circuit:
The power consumed in the 9 Ω resistance is ..........

1. A $\dfrac{5}{4}$ W
2. B $\dfrac{3}{7}$ W
3. C $\dfrac{6}{5}$ W
4. D $\dfrac{4}{9}$ W

Two identical resistances x and y, connected as in the opposite circuit, each consume a power $P_w$. What power do the resistances x and y consume respectively when:
the switch $K_1$ is closed?

1. A x: $4 P_w$, y: $2 P_w$
2. B x: $16 P_w$, y: $4 P_w$
3. C x: $\dfrac{P_w}{4}$, y: $\dfrac{P_w}{2}$
4. D x: $\dfrac{P_w}{16}$, y: $\dfrac{P_w}{4}$

Two identical resistances x and y, connected as in the opposite circuit, each consume a power $P_w$. What power do the resistances x and y consume respectively when:
the switch $K_3$ is opened and the switch $K_2$ is closed?

1. A x: $\dfrac{3}{2} P_w$, y: $2 P_w$
2. B x: $\dfrac{P_w}{4}$, y: $\dfrac{P_w}{8}$
3. C x: $9 P_w$, y: $9 P_w$
4. D x: $\dfrac{2 P_w}{3}$, y: $\dfrac{2 P_w}{3}$

The opposite circuit contains two identical lamps (1) and (2). When the slider is moved from position a to position b, what happens to the brightness of:
lamp (1)?

1. A decreases
2. B increases
3. C does not change
4. D becomes zero

The opposite circuit contains two identical lamps (1) and (2). When the slider is moved from position a to position b, what happens to the brightness of:
lamp (2)?

1. A decreases
2. B increases
3. C does not change
4. D becomes zero

In the circuit shown in the figure:
(1) Write the relation between each of the readings $V_1$ and $V_2$ and the current I flowing in the circuit.
(2) Deduce what happens to the readings $V_1$ and $V_2$ when the resistance of the rheostat S is increased.
(3) What are the readings of $V_1$ and $V_2$ when the switch K is opened?

In the circuit shown in the figure, calculate the emf of the source if its internal resistance is $2\ \Omega$

In the circuit shown, if the emf of the battery is 12 V and its internal resistance is $2\ \Omega$, find the readings of the ammeter (A), the voltmeter $(V_1)$ and the voltmeter $(V_2)$ when the switch K is:
(1) open. (2) closed.

In the two opposite circuits (1) and (2), a variable resistance R is connected once to a source of emf $V_B$ with negligible internal resistance, and once to a source of emf $V_B$ and internal resistance r. When R is increased in both circuits, the reading of voltmeter $V_1$ stays constant while the reading of voltmeter $V_2$ increases. Explain why.

In the circuit shown in the following figure, the resistance $R_1$ is twice the internal resistance (r) of the source, and the reading of voltmeter (V) across the source is five times the reading of voltmeter $(V_1)$ across $R_1$. Find the resistance $R_2$ in terms of the internal resistance (r) of the source.

In the circuit shown, what happens to the voltmeter reading when the slider is moved from point x to point y?

A closed circuit consists of a battery of emf $V_B$ and internal resistance r, a variable resistance R and an ammeter. When R was doubled, the ammeter reading did not drop to half. Does this agree with Ohm's law or not? Explain your answer.

From the data of the opposite circuit, is the internal resistance of the battery significant or negligible? Explain your answer.

Figures (1) and (2) each represent part of a different circuit. Find the ratio between the potential differences $\frac{V_{xy}}{V_{zk}}$

In the opposite circuit, the potential of point x is higher than the potential of point y, the ammeter reads 2 A and the internal resistance of each battery is $1\ \Omega$. Calculate the emf of the battery $(V_B)_2$

In the opposite figure, which is greater? Explain.
(1) The emf of the battery $(V_B)_1$ or the reading of voltmeter $V_1$?
(2) The emf of the battery $(V_B)_2$ or the reading of voltmeter $V_2$?

The opposite figure shows a closed circuit containing an unknown element Z. Given that the internal resistances of the sources in the circuit are negligible, suggest two possibilities for the unknown element Z that give the values shown in the figure.

In the two opposite circuits (1) and (2), what is the effect of closing the switch K on the brightness of lamp x?

In the circuit shown in the figure, explain what happens to the brightness of lamp x when the switch $K_1$ is opened and the switch $K_2$ is closed.

Two identical lamps, each marked (60 W, 12 V), are connected to a battery of emf 12 V and internal resistance $0.5\ \Omega$ as in the opposite figure. Explain why the power consumed by each lamp is not 60 W

The following figures show four circuits, each containing an ammeter. What is the correct order of the readings of the ammeters $A_1$, $A_2$, $A_3$ and $A_4$? (Trial exam / May 2021)

1. A $A_3 > A_1 > A_2 > A_4$
2. B $A_2 > A_1 > A_3 > A_4$
3. C $A_1 > A_2 > A_4 > A_3$
4. D $A_3 > A_4 > A_2 > A_1$

A cell is connected to a resistance $R_1$ and the current in the circuit is 0.5 A, as in figure (1). When $R_1$ is replaced by a resistance $R_2$, the current in the circuit becomes 0.3 A, as in figure (2). The emf of the cell is .......... (Trial exam / May 2021)

1. A 1.2 V
2. B 1.5 V
3. C 2 V
4. D 3 V

The opposite figure represents two circuits. The ratio $\frac{I_1}{I_2}$ is .......... (Trial exam / June 2021)

1. A $\frac{6}{11}$
2. B $\frac{11}{6}$
3. C $\frac{1}{2}$
4. D $\frac{1}{1}$

From the circuit in front of you, the ratio between the readings of the two voltmeters $\frac{V_1}{V_2}$ = .......... (1st session 2021)

1. A $\frac{V_B + Ir}{IR}$
2. B $\frac{IR}{V_B + V_2}$
3. C $\frac{IR - Ir}{V_2 - V_B}$
4. D $\frac{V_B - Ir}{IR}$

In the circuit in front of you, the current I is .......... (1st session 2021)

1. A 0.76 A
2. B 0.83 A
3. C 3 A
4. D 4 A

In the closed circuit shown in the figure, when the value of the variable resistance (S) is increased, .......... (2nd session 2021)

1. A the readings of both $V_1$ and $V_2$ increase
2. B the reading of $V_1$ increases and the reading of $V_2$ decreases
3. C the reading of $V_1$ decreases and the reading of $V_2$ increases
4. D the readings of both $V_1$ and $V_2$ decrease

In the circuit shown in the figure, if the reading of $V_3$ is 0.8 V, which of the following choices correctly gives the readings of $V_1$ and $V_2$ respectively? (2nd session 2021)

1. A $V_1$ = 10 V , $V_2$ = 6 V
2. B $V_1$ = 8.4 V , $V_2$ = 9.2 V
3. C $V_1$ = 7.6 V , $V_2$ = 9.2 V
4. D $V_1$ = 4 V , $V_2$ = 8 V

When the value of the variable resistance (S) in the circuit shown is increased, which choice correctly describes the change in the readings of voltmeter $(V_1)$ and voltmeter $(V_2)$ respectively? (1st session 2022)

1. A $V_1$ increases , $V_2$ increases
2. B $V_1$ stays constant , $V_2$ increases
3. C $V_1$ decreases , $V_2$ stays constant
4. D $V_1$ decreases , $V_2$ decreases

In the circuit shown, if the voltmeter reads 18 V while the switch (K) is open, and 15 V when it is closed, the internal resistance of the battery is .......... (1st session 2022)

1. A $3\ \Omega$
2. B $2\ \Omega$
3. C $4\ \Omega$
4. D $1\ \Omega$

In the circuit shown in the figure, the voltmeter read 14 volts while the switch K was open, and when K was closed its reading became 8 volts. The internal resistance of the battery is .......... (2nd session 2022)

1. A $1.25\ \Omega$
2. B $0.5\ \Omega$
3. C $1.5\ \Omega$
4. D $0.25\ \Omega$

In the circuit shown in the figure, what happens to the voltmeter reading when the resistance taken from the rheostat is changed? (Trial exam 2023)

1. A Decreasing the rheostat resistance: the voltmeter reading decreases
2. B Decreasing the rheostat resistance: the voltmeter reading increases
3. C Increasing the rheostat resistance: the voltmeter reading decreases
4. D Increasing the rheostat resistance: the voltmeter reading does not change

The graph shows the relation between the potential difference (V) between the terminals of a battery of internal resistance $0.5\ \Omega$, connected in a closed circuit, and the current (I) in the circuit. The emf of the battery is .......... (Trial exam 2023)

1. A 8 V
2. B 10 V
3. C 9 V
4. D 12 V

In the circuit shown in the figure, which choice correctly gives the values of $V_B$, $I_1$ and $I_2$ respectively? (Trial exam 2023)

1. A $V_B$ = 6 V , $I_1$ = 2 A , $I_2$ = 1 A
2. B $V_B$ = 18 V , $I_1$ = 3 A , $I_2$ = 1 A
3. C $V_B$ = 18 V , $I_1$ = 1 A , $I_2$ = 2 A
4. D $V_B$ = 6 V , $I_1$ = 3 A , $I_2$ = 2 A

The figure represents a closed circuit. When the switch (K) is opened, .......... (1st session 2023)

1. A the ammeter reading decreases and the voltmeter reading increases
2. B the ammeter reading increases and the voltmeter reading decreases
3. C the readings of both the ammeter and the voltmeter decrease
4. D the readings of both the ammeter and the voltmeter increase

From the figure in front of you, we find that .......... (2nd session 2023)

1. A $V_2 < V_B$
2. B $V_1 > V_B$
3. C $V_2 = V_B$
4. D $V_1 = V_2$

The opposite figure shows a certain battery connected in two different circuits. If the ammeter reads 1.2 A in the first circuit and 1 A in the second circuit, the internal resistance of the battery (r) is .......... (2nd session 2023)

1. A $1.5\ \Omega$
2. B $2\ \Omega$
3. C $0.5\ \Omega$
4. D $1\ \Omega$

You have a circuit as in the figure. Which of the following choices for the voltmeter reading is correct? (1st session 2024)

1. A K open: $\frac{4}{3} V_B$ , K closed: $\frac{6}{5} V_B$
2. B K open: $\frac{4}{3} V_B$ , K closed: $\frac{7}{5} V_B$
3. C K open: $\frac{7}{6} V_B$ , K closed: $\frac{6}{5} V_B$
4. D K open: $\frac{7}{6} V_B$ , K closed: $\frac{7}{5} V_B$

The opposite figure represents a circuit. If the voltmeter reads 4 V when the switch K is open, the potential difference across the $3\ \Omega$ resistance when K is closed is .......... volts. (2nd session 2024)

1. A 4
2. B 8
3. C 6
4. D 9

In the circuit shown in the figure, the internal resistance of the battery is $0.5\ \Omega$, the voltmeter reads 21 V while the switch K is open and 19.5 V when K is closed. The current in the circuit and the value of the resistance R respectively are .......... (Sample exam 2025)

1. A I = 2 A , R = $10\ \Omega$
2. B I = 2 A , R = $13\ \Omega$
3. C I = 3 A , R = $10\ \Omega$
4. D I = 3 A , R = $13\ \Omega$

The opposite figure shows part of a circuit. The voltmeter reading (V) is calculated from the relation .......... (Sample exam 2025)

1. A $V = V_B - I(R + r)$
2. B $V = V_B - I(R - r)$
3. C $V = V_B + I(R + r)$
4. D $V = V_B + I(R - r)$

In the circuit in the opposite figure, if the potential difference between the points a and b is 15.2 V, the value of r and the potential difference between the points (c) and (d) respectively are .......... (Sample exam 2025)

1. A r = $1.4\ \Omega$ , $V_{cd}$ = 7.7 V
2. B r = $1.4\ \Omega$ , $V_{cd}$ = 7.8 V
3. C r = $0.7\ \Omega$ , $V_{cd}$ = 7.7 V
4. D r = $2.8\ \Omega$ , $V_{cd}$ = 8.4 V

In the opposite circuit, a group of different resistances is connected to a battery of internal resistance R. Which of the following relations between the potential differences across the external resistances is correct? (Sample exam 2025)

1. A $V_{3R} = 3 V_R = 3 V_{2R} = 1.5 V_{4R}$
2. B $V_{3R} = 3 V_R = 1.5 V_{2R} = 0.75 V_{4R}$
3. C $V_{3R} = 2 V_R = V_{2R} = V_{4R}$
4. D $V_{3R} = 2 V_R = 3 V_{2R} = 1.5 V_{4R}$

In the circuit shown in the figure, what happens to the readings of the two voltmeters $(V_1)$ and $(V_2)$ when the value of the variable resistance $(R_2)$ is increased? (1st session 2025)

1. A $V_1$ decreases , $V_2$ decreases
2. B $V_1$ decreases , $V_2$ increases
3. C $V_1$ increases , $V_2$ decreases
4. D $V_1$ increases , $V_2$ increases

Three identical lamps, each of resistance (R), are connected to a battery of emf $(V_B)$ and internal resistance (0.5 R) as in the figure. When the filament of lamp (Y) burns out, what happens to the brightness of lamps (X) and (Z)? (1st session 2025)

1. A X increases , Z increases
2. B X increases , Z decreases
3. C X decreases , Z increases
4. D X decreases , Z decreases

The circuit shown in the figure contains a resistance R connected to a battery of emf $V_B$ and internal resistance r. What happens to the readings of the two voltmeters $V_1$ and $V_2$ when the switch K is opened? (2nd session 2025)

1. A $V_1$ increases to $V_B$ , $V_2$ increases to $V_B$
2. B $V_1$ increases to $V_B$ , $V_2$ decreases to zero
3. C $V_1$ decreases to zero , $V_2$ increases to $V_B$
4. D $V_1$ decreases to zero , $V_2$ decreases to zero

The figure shows a resistance of $20\ \Omega$ connected across the terminals of a battery of emf 12 V and internal resistance $4\ \Omega$. If a voltmeter of resistance $80\ \Omega$ is connected in parallel across this resistance, what is the voltmeter reading? (2nd session 2025)

1. A 12 V
2. B 10 V
3. C 9.6 V
4. D 2.4 V

In the circuit shown in the figure, the ammeter reading is (I), the voltmeter reading is (V) and the internal resistance of the battery is (r = 0.5 R). What happens to the readings of the ammeter and the voltmeter when the switch (K) is closed? (2nd session 2025)

1. A ammeter increases , voltmeter decreases
2. B ammeter increases , voltmeter increases
3. C ammeter decreases , voltmeter decreases
4. D ammeter decreases , voltmeter increases

The figure shows a circuit consisting of a battery of emf 4 V and internal resistance $0.35\ \Omega$ connected to a fixed resistance (R) and a metal wire (XY) 90 cm long with a cross-sectional area of $3 \times 10^{-8}\ m^2$. If the voltmeter reads 3.3 V while the p.d. between point (X) and point (Y) is 1.8 V, then .......... (Sample exam 2026)

1. A external equivalent resistance $1.65\ \Omega$ , conductivity $33.33 \times 10^{6}\ \Omega^{-1} m^{-1}$
2. B external equivalent resistance $0.9\ \Omega$ , conductivity $33.33 \times 10^{6}\ \Omega^{-1} m^{-1}$
3. C external equivalent resistance $1\ \Omega$ , conductivity $3 \times 10^{8}\ \Omega^{-1} m^{-1}$
4. D external equivalent resistance $0.75\ \Omega$ , conductivity $3 \times 10^{8}\ \Omega^{-1} m^{-1}$

Using the data on the opposite circuit, when only the switch $(K_1)$ is closed, the p.d. between the points B and D is .......... while when only the switch $(K_2)$ is closed, the p.d. between the points D and F is .......... (Sample exam 2026)

1. A $V_{BD}$ = 14 V , $V_{DF}$ = 6 V
2. B $V_{BD}$ = 6 V , $V_{DF}$ = 16 V
3. C $V_{BD}$ = 6 V , $V_{DF}$ = 6 V
4. D $V_{BD}$ = 26 V , $V_{DF}$ = 18 V

The opposite figure represents a circuit. When only $K_1$ and $K_3$ are closed, a current of 0.8 A flows, and when only $K_2$ and $K_3$ are closed, a current of 0.6 A flows. Calculate the value of $V_B$ (1st session 2024)

A battery of emf 18 V and internal resistance $2\ \Omega$ is connected to a resistance R, and the p.d. between the terminals of the battery is 12 V. If another resistance of $12\ \Omega$ is connected in parallel with R, calculate the current in the circuit in the second case. (2nd session 2024)