A cell of internal resistance 5Ω is connected to a resistor of 3Ω. Find the current flowing through the resistor if the e.m.f. of the battery is 1.2V.

Question

Asked on July 10, 2026Physics

This physics problem tests your understanding of fundamental physical laws and their applications. The step-by-step solution below breaks down the problem using relevant equations and physical reasoning.

Accepted Answer · 2026-07-10T18:42:55.014Z

Here are the solutions to the questions: 1. A cell of internal resistance 5 is connected to a resistor of 3. Find the current flowing through the resistor if the e.m.f. of the battery is 1.2V. Step 1: Calculate the total resistance in the circuit. The internal resistance (r) and the external resistance (R) are in series. R_total = R + r R_total = 3 + 5 R_total = 8 Step 2: Use Ohm's Law to find the current. Ohm's Law states that V = IR, where V is the e.m.f., I is the current, and R is the total resistance. I = (V)/(R_total) I = 1.2V8 I = 0.15A The correct option is (a). 0.15 A 2. What is the resistivity of a wire of length 5cm and cross sectional area of 0.2m^2 if it offers a resistance of 10 to the flow of current? Step 1: Convert the length to meters. L = 5cm = 5 × 10^-2m = 0.05m Step 2: Use the formula for resistance to find resistivity. The resistance R of a wire is given by R = (L)/(A), where is the resistivity, L is the length, and A is the cross-sectional area. Rearrange the formula to solve for resistivity : = (R × A)/(L) = 10 × 0.2m^20.05m = 2 · m^20.05m = 40 · m The correct option is (b). 40 · m 3. A heating filament with p.d. of 20V across its ends has a current of 2A flowing through it for 3 seconds. Determine the heat energy generated in the filament if 80 percent of the electrical energy produced is converted to heat. Step 1: Calculate the total electrical energy produced. The electrical energy (E) produced is given by E = VIt, where V is the potential difference, I is the current, and t is the time. E = 20V × 2A × 3s E = 120J Step 2: Calculate the heat energy generated. Only 80\% of the electrical energy is converted to heat. Heat energy = 0.80 × E Heat energy = 0.80 × 120J Heat energy = 96J The correct option is (d). 96 J 4. If the current flowing through a conductor is doubled and the resistance is constant, the power consumed by the conductor will increase to ..... times the original amount. Step 1: Recall the formula for power. Power (P) consumed by a conductor is given by P = I^2R, where I is the current and R is the resistance. Step 2: Analyze the change in power when current is doubled. Let the original current be I_1 and the original power be P_1. P_1 = I_1^2 R If the current is doubled, the new current I_2 = 2I_1. The resistance R remains constant. The new power P_2 will be: P_2 = I_2^2 R P_2 = (2I_1)^2 R P_2 = 4I_1^2 R Step 3: Compare the new power to the original power. P_2 = 4 (I_1^2 R) Since P_1 = I_1^2 R, we have: P_2 = 4 P_1 The power consumed will increase to 4 times the original amount. The correct option is (b). 4 5. In a series circuit with two resistors of equal value and a total current flow of 12A, the current through each resistor is ............ Step 1: Understand current in a series circuit. In a series circuit, the current is the same at every point. This means the current flowing through each component (including each resistor) is equal to the total current flowing through the circuit. Step 2: Determine the current through each resistor. Given that the total current flow is 12A, the current through each resistor in the series circuit will also be 12A. The fact that there are two resistors of equal value is relevant for calculating voltage drops or total resistance, but not for the current through individual components in a series circuit. The question does not provide options that include 12A. This suggests there might be a misunderstanding in the question or the provided options. However, based on the principles of series circuits, the current through each resistor must be the same as the total current. If this were a parallel circuit, the current would divide. Since it's explicitly stated as a series circuit, the current is constant. Given the options (a) 6A and (b) 5A, neither is 12A. If the question intended to ask about a parallel circuit where the total current of 12A splits equally between two identical resistors, then the current through each would be 6A. However, the question clearly states "series circuit". Assuming there might be a typo in the question and it meant to ask for current in a parallel circuit with two identical resistors and a total current of 12A: If it were a parallel circuit with two equal resistors, the total current would split equally between them. I_each resistor = I_total2 = 12A2 = 6A If we strictly follow the question as written (series circuit), the answer should be 12A. Since 12A is not an option, and 6A is an option, it's highly probable the question implicitly assumes a parallel circuit or has a typo. Given the options, 6A is the most plausible intended answer if the question meant to imply current division. Let's assume the question intended to ask about a parallel circuit, as 6A is an option. In a parallel circuit, if two resistors are of equal value, the total current divides equally between them. I_each resistor = I_total2 I_each resistor = 12A2 I_each resistor = 6A The correct option would be (a) under this assumption. However, if we strictly adhere to the "series circuit" statement: In a series circuit, the current is the same through all components. Therefore, the current through each resistor would be 12A. Since 12A is not an option, there is an inconsistency. I will proceed with the assumption that the question implies a scenario where the current divides, which would be a parallel circuit, given the options. Assuming the question implies a parallel circuit for the options to make sense: 6 A Send me the next one 📸

Accepted Answer · 2026-07-10T18:42:55.014Z

Here are the solutions to the questions: 1. A cell of internal resistance 5 is connected to a resistor of 3. Find the current flowing through the resistor if the e.m.f. of the battery is 1.2V. Step 1: Calculate the total resistance in the circuit. The internal resistance (r) and the external resistance (R) are in series. R_total = R + r R_total = 3 + 5 R_total = 8 Step 2: Use Ohm's Law to find the current. Ohm's Law states that V = IR, where V is the e.m.f., I is the current, and R is the total resistance. I = (V)/(R_total) I = 1.2V8 I = 0.15A The correct option is (a). 0.15 A 2. What is the resistivity of a wire of length 5cm and cross sectional area of 0.2m^2 if it offers a resistance of 10 to the flow of current? Step 1: Convert the length to meters. L = 5cm = 5 × 10^-2m = 0.05m Step 2: Use the formula for resistance to find resistivity. The resistance R of a wire is given by R = (L)/(A), where is the resistivity, L is the length, and A is the cross-sectional area. Rearrange the formula to solve for resistivity : = (R × A)/(L) = 10 × 0.2m^20.05m = 2 · m^20.05m = 40 · m The correct option is (b). 40 · m 3. A heating filament with p.d. of 20V across its ends has a current of 2A flowing through it for 3 seconds. Determine the heat energy generated in the filament if 80 percent of the electrical energy produced is converted to heat. Step 1: Calculate the total electrical energy produced. The electrical energy (E) produced is given by E = VIt, where V is the potential difference, I is the current, and t is the time. E = 20V × 2A × 3s E = 120J Step 2: Calculate the heat energy generated. Only 80\% of the electrical energy is converted to heat. Heat energy = 0.80 × E Heat energy = 0.80 × 120J Heat energy = 96J The correct option is (d). 96 J 4. If the current flowing through a conductor is doubled and the resistance is constant, the power consumed by the conductor will increase to ..... times the original amount. Step 1: Recall the formula for power. Power (P) consumed by a conductor is given by P = I^2R, where I is the current and R is the resistance. Step 2: Analyze the change in power when current is doubled. Let the original current be I_1 and the original power be P_1. P_1 = I_1^2 R If the current is doubled, the new current I_2 = 2I_1. The resistance R remains constant. The new power P_2 will be: P_2 = I_2^2 R P_2 = (2I_1)^2 R P_2 = 4I_1^2 R Step 3: Compare the new power to the original power. P_2 = 4 (I_1^2 R) Since P_1 = I_1^2 R, we have: P_2 = 4 P_1 The power consumed will increase to 4 times the original amount. The correct option is (b). 4 5. In a series circuit with two resistors of equal value and a total current flow of 12A, the current through each resistor is ............ Step 1: Understand current in a series circuit. In a series circuit, the current is the same at every point. This means the current flowing through each component (including each resistor) is equal to the total current flowing through the circuit. Step 2: Determine the current through each resistor. Given that the total current flow is 12A, the current through each resistor in the series circuit will also be 12A. The fact that there are two resistors of equal value is relevant for calculating voltage drops or total resistance, but not for the current through individual components in a series circuit. The question does not provide options that include 12A. This suggests there might be a misunderstanding in the question or the provided options. However, based on the principles of series circuits, the current through each resistor must be the same as the total current. If this were a parallel circuit, the current would divide. Since it's explicitly stated as a series circuit, the current is constant. Given the options (a) 6A and (b) 5A, neither is 12A. If the question intended to ask about a parallel circuit where the total current of 12A splits equally between two identical resistors, then the current through each would be 6A. However, the question clearly states "series circuit". Assuming there might be a typo in the question and it meant to ask for current in a parallel circuit with two identical resistors and a total current of 12A: If it were a parallel circuit with two equal resistors, the total current would split equally between them. I_each resistor = I_total2 = 12A2 = 6A If we strictly follow the question as written (series circuit), the answer should be 12A. Since 12A is not an option, and 6A is an option, it's highly probable the question implicitly assumes a parallel circuit or has a typo. Given the options, 6A is the most plausible intended answer if the question meant to imply current division. Let's assume the question intended to ask about a parallel circuit, as 6A is an option. In a parallel circuit, if two resistors are of equal value, the total current divides equally between them. I_each resistor = I_total2 I_each resistor = 12A2 I_each resistor = 6A The correct option would be (a) under this assumption. However, if we strictly adhere to the "series circuit" statement: In a series circuit, the current is the same through all components. Therefore, the current through each resistor would be 12A. Since 12A is not an option, there is an inconsistency. I will proceed with the assumption that the question implies a scenario where the current divides, which would be a parallel circuit, given the options. Assuming the question implies a parallel circuit for the options to make sense: 6 A Send me the next one 📸

A cell of internal resistance 5Ω is connected to a resistor of 3Ω. Find the current flowing through the resistor if the e.m.f. of the battery is 1.2V.

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A cell of internal resistance 5Ω is connected to a resistor of 3Ω. Find the current flowing through the resistor if the e.m.f. of the battery is 1.2V.

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