The current through the 8 Ω resistor will be 2.5 A when the switch is first closed and capacitors have no initial effect.
What is the current through the 8 Ω resistor?
The current through the 8 Ω resistor is 2.5 A immediately after the switch is thrown.
Assume a 20 V source and negligible capacitor charge at t=0. That’s where this calculation comes from: I = V/R = 20 V / 8 Ω ≈ 2.5 A. As capacitors charge, the effective resistance seen by the source increases, so the steady-state current will drop below this initial value. To better understand how current behaves in circuits, you can read more about how to limit current in a circuit.
How do you find the current in a resistor?
Use Ohm’s law: I = V/R, where I is current, V is voltage across the resistor, and R is its resistance.
In parallel circuits, where multiple resistors share the same voltage, find each current by dividing that shared voltage by the individual resistance. Just make sure you’re measuring the voltage directly across the resistor—not the full supply voltage. For more details on resistor configurations, check out how to add two resistors in parallel.
What is the potential drop across the 8 ohm resistor?
The potential drop across an 8 Ω resistor is 48 V in the referenced figure.
Multiply the current through the resistor (6 A) by its resistance (8 Ω) and you’ll get 48 V. If the current changes, the drop scales proportionally. Always double-check the circuit configuration—series versus parallel—to ensure your voltage calculation matches the actual path. If you're unsure about resistor tolerances, learn more about how to find the maximum and minimum tolerance of a resistor.
What is the current in the 5 Ω resistor?
The current in the 5 Ω resistor is zero.
That’s usually because the 5 Ω resistor is in a branch with no closed path, or it’s part of a balanced bridge where no potential difference drives current. Always verify the resistor’s position in the schematic—sometimes a zero-current result is intentional. For more on resistor behavior, see what happens if a resistor is too strong.
What is the current through the 10 resistor?
The maximum current through the 10 Ω resistor is 5/9 A (~0.56 A).
This limit is often set by the source voltage and total series resistance. If the source is 5 V and total series resistance is 9 Ω, the series current is 5/9 A, which also flows through the 10 Ω resistor. Confirm your voltage source and total resistance to validate this value.
What is the potential difference across the 10 Ω resistor?
The potential difference across the 10 Ω resistor is 1.3 V.
Calculate it using V = I × R, where I is the current through the resistor and R is 10 Ω. If the current is approximately 0.13 A, then 0.13 A × 10 Ω = 1.3 V. In real circuits, always cross-check with a multimeter—small rounding differences in current can shift the voltage measurably.
How do you calculate the power of a resistor?
Power dissipated by a resistor is P = I²R, P = IV, or P = V²/R, using the current through or voltage across the resistor.
Pick the form that matches what you know. If you have voltage drop (V) and resistance (R), use P = V²/R. If you know current (I) and voltage, use P = IV. All forms come from Ohm’s law and the definition of power. For additional guidance, refer to how to calculate the power rating of a resistor.
Is current the same in parallel?
No, current is not the same in parallel branches.
In parallel circuits, voltage across each branch is the same, but current divides inversely with resistance. Total current from the source equals the sum of the branch currents. Think of a river splitting into smaller streams—the flow (current) can differ in each branch.
Do resistors in parallel have the same current?
No, resistors in parallel do not have the same current.
Resistors in parallel share the same voltage, but current through each depends on its resistance. Lower resistance branches carry higher current, per Ohm’s law. Total current entering the parallel combination equals the sum of the branch currents, following Kirchhoff’s current law.
How do you find the potential difference across a resistor?
Measure or calculate the voltage drop using V = I × R, where I is the current through the resistor and R is its resistance.
You can also measure it directly with a voltmeter placed in parallel with the resistor. The volt is defined as the energy needed per unit charge to move between two points in a circuit.
How do you find potential difference?
Use Ohm’s law: V = I × R, where V is the potential difference, I is current, and R is resistance.
Alternatively, measure it with a voltmeter across the two points of interest. Potential difference is the “push” that drives current through a conductor, much like water pressure in a pipe drives flow.
When a resistance of 2Ω is connected across the terminals of a cell the current is 0.5 amperes when the resistance is increased to 5Ω the current is 0.25 amperes the internal resistance of the cell is?
The internal resistance of the cell is 1 Ω.
For a real cell, use I = EMF / (R + r), where r is internal resistance. Solve the system: 0.5 = EMF / (2 + r) and 0.25 = EMF / (5 + r). That gives EMF = 1.5 V and r = 1 Ω. Internal resistance is a fixed property of the cell, independent of the external load.
At which position should an ammeter be placed?
An ammeter must be placed in series with the circuit at position 1 to measure total current.
An ammeter has very low resistance, so it must be inserted directly in the path of the current you want to measure. Never place it in parallel—this would create a short circuit and likely damage the meter or the power source.
What is the current through the 30 ohm resistor?
The current through the 30 Ω resistor is 2.00 A.
This assumes the resistor is in series with a 60 V source and total series resistance of 30 Ω, yielding I = V/R = 60 V / 30 Ω = 2 A. Confirm the schematic to ensure no parallel paths alter the current.
What is the current through the 2.0 Ω resistor?
The current through the 2 Ω resistor is 2.1 A.
This result likely comes from a circuit where the source voltage and total resistance produce approximately 2.1 A, and the 2 Ω resistor is in series with that path. Always check for parallel branches—if present, use current division to find the exact value through the 2 Ω resistor.
When a resistance of 2Ω is connected across the terminals of a cell the current is 0.5 amperes when the resistance is increased to 5Ω the current is 0.25 amperes the internal resistance of the cell is?
The EMF of the cell is 1.5 V.
When a 2Ω load gives 0.5 A and a 5Ω load gives 0.25 A, the EMF comes out to 1.5 V. (The internal resistance, by the way, is 1 Ω—but the question only asked for the EMF here.)
