Unit 2: 4 - Current Electricity Flashcards Preview

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Flashcards in Unit 2: 4 - Current Electricity Deck (20)
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1
Q

What happens when 2 electrically insulating objects rub against each other?

A

Electrons are rubbed off one material and deposited onto the other.

2
Q

The material which gains electrons becomes _____ charged. What is this called?

A

Negatively. Charging by friction.

3
Q

What will happen if 2 negatively/positively charged objects come close to each other?

A

Repel

4
Q

How do we work out the current using Coulombs?

A

I=Q/t

Current = Coulombs / Time

5
Q

What is the unit of Potential Difference?

A

Volt

6
Q

How is Potential Difference worked out using Work Done?

A

V=W/Q

Voltage (V) = Work done (J) / Charge in Coulombs (Q)

7
Q

What does Ohm’s Law state?

A

The current through a resistor at constant temperature is directionally proportional to the potential difference across the resistor.

8
Q

Reversing the current through a component reverses the _____ _____ across it.

A

Potential Difference.

9
Q

How do we work out the resistance?

A

R=V/I

Resistance (Ohms) = PD (V) / Current (I)

10
Q

What is an component classified as when it obeys Ohm’s law?

A

An Ohmic Conductor

11
Q

In what way does a current flow through a diode?

A

In one direction, as the resistance is too high.

12
Q

How does the resistance of a Light Dependant Resistor change with the light intensity?

A

As the light intensity gets larger, the resistance goes up.

13
Q

How does the resistance of a thermistor change with temperature?

A

As the temperature goes up, the resistance of a thermistor goes down.

14
Q

What is a series circuit?

A

When components are connected one after another. If there is a break anywhere in the circuit, the charge stops flowing.

15
Q

How do we work out the current using the resistance?

A

I=V/R

Current = PD / Resistance

16
Q

How do we work out the total resistance of a circuit?

A

The sum of all the resistances of the components in the circuit.

17
Q

How is a parallel circuit arranged?

A

Each component is connected across the supply; if there is a break in one part of the curcuit, charge can still flow through the other components.

18
Q

The sum of the current through the whole circuit is equal to the sum of the currents through the _____ components.

A

Separate

19
Q

Define current.

A

Rate of flow of charge.

20
Q

What is potential difference?

A

Work done / energy transferred per coulomb of charge.