Current | Electricity | Physics | FuseSchool

Summary

This video explains the concept of electric current, how it is measured, and how to calculate it. Current is the rate of flow of electric charge through a conductor, typically measured in amperes (amps) using an ammeter. The video also discusses the importance of potential difference (voltage) and a complete circuit for current to flow. It explains the differences between series and parallel circuits, highlighting how current is distributed. The video concludes with examples to help viewers understand the relationship between charge, current, and time.

Takeaways

• 🔌 Current is the rate of flow of charge through a cross-section of an electrical conductor.
• 🧲 Electric charge can be understood as the movement of electrons.
• 🔧 Current is measured using an ammeter, and its unit is amperes (amps).
• 🔄 Ammeters must be connected in series within a circuit, with the current flowing into the positive terminal and out through the negative terminal.
• ⚡ Charge flows when there is a source of potential difference (voltage) and a complete circuit without any breaks.
• 💡 A switch works by creating or closing a break in a circuit, allowing or stopping current flow.
• 📏 In a series circuit, all components are arranged in a line, and the current is the same at every point in the circuit.
• 🔀 In parallel circuits, current is shared between different branches, and the total current is the sum of the currents in each branch.
• 📐 Current can be calculated using the formula: Current = Charge / Time.
• 📘 The relationship between charge, current, and time can be remembered using the acronym QIT (Charge = Current x Time).

Q & A

What is electric current?

Electric current is the rate of flow of charge through a cross-section of an electrical conductor. It can also be thought of as the movement of electrons.

How is electric current measured?

Electric current is measured using an ammeter, and the unit of current is amperes (amps).

How should an ammeter be connected in a circuit?

An ammeter must be connected in series in a circuit, with the current flowing into the positive terminal and leaving through the negative terminal.

What are the two conditions needed for charge to flow and create current?

The two conditions are: (1) A source of potential difference (voltage), and (2) A complete circuit with no breaks.

What happens when there is a break in a circuit?

If there is a break in the circuit, no current can flow. This is how a switch works, by creating a break to stop the current or closing the break to allow current to flow.

How does current behave in a series circuit?

In a series circuit, all the components are in a line, and all the electrons travel through every component and wire at the same rate. As a result, the current readings on all ammeters in the series will be the same.

How does current behave in a parallel circuit?

In a parallel circuit, the current is shared between the different branches. The total current entering a junction equals the sum of the currents in the individual branches.

What formula can be used to calculate current?

The formula to calculate current is: Current (I) = Charge (Q) ÷ Time (T).

What is the relationship between current, charge, and time?

Current is the rate of flow of charge over time, meaning that Current (I) = Charge (Q) ÷ Time (T). Charge can also be calculated as Q = I × T.

How can you find the current if the charge is 60 coulombs and the time is 15 seconds?

Using the formula I = Q ÷ T, the current would be 60 coulombs ÷ 15 seconds = 4 amps.