# SP10 - Electricity and Circuits ✓ Flashcards

SP10a - Describe the structure of an atom including features of the sub-atomic particles.

- Proton and neutron in the nucelus, each with a relative mass of 1.
- Protons have a charge of +1.
- Electrons orbit in energy levels each with a charge of -1 and a relative mass of 1/1835 (negligible)

SP10a - Descirbe what a potential difference is.

The force that pushes the electrons to flow around the circuit.

SP10a - What is conventional current?

What we refer to as the direciton of current form positive to negative. Opposite to the flow of electrons.

SP10a - What are the two types of circuits?

- Series: everything connected in one route
- Parallel: many options for different routes.

SP10a - Why may parallel circuits be more beneficial?

- If the circuit becomes incomplete along one path, the rest of the circuit can still continue to function. (e.g - Switches can be connected to different parts meaning lights in parallel to each other can be switched in and off individually)
- If a bulb goes off, the rest of the circuit in parallel to this can still continue to function

SP10b - What is the unit for current and how can it be measured?

Amps (Amperes). Measured using an ammeter which is attached in series to the circuit

SP10b - What is the unit for potential difference and how can it be measured?

Volts. Measured using a voltmeter which is attached in parallel to the component you are measuring the potential difference of.

SP10b - How does total current differ in parallel and series circuits?

- S: The total current is the same at all points throughout the circuit
- P: The total current gets split between the branches of the circuit, inversely proportionate to the resistance of the components in those branches.

SP10b - How does potential difference differ in parallel and series circuits?

- S: The p.d is different across different components, directly proportionate to the resistance of that component
- P: The p.d is tha same at all points across the circuit

SP10c - What is current?

- The flow of electrons
- The rate of flow of charge

SP10c - What is the unit for charge?

C - Coulombs

SP10c - What is the equation linking charge and current?

Q = I x t

(Charge = Current x time)

SP10c - What equation links energy and charge and how can this be changed to link energy to current?

**E = Q x V** (Energy = Charge x p.d)

since **Q = I x t**, this means that

**E = I x t x V** (Energy = Current x time x p.d)

SP10d - What is Ohm’s law?

V = I x R

(p.d (V) = Current (A) x Resistance (Ω))

SP10d - What is resistance?

The force pushing back against p.d opposing and reducing the current.

SP10d - How do you calculate the resistance in series and parallel circuits?

- Series: Add up the resistance of all the components
- Parallel: 1/R
_{T}= 1/R_{1}+ 1/R_{2 }+ ………..