New
New
Year 10
OCR
Higher

Moving electric charge

I can explain how an electric field causes electric current to flow in a circuit.

New
New
Year 10
OCR
Higher

Moving electric charge

I can explain how an electric field causes electric current to flow in a circuit.

Lesson details

Key learning points

  1. Two unlike electric charges attract each other.
  2. Two like electric charges repel each other.
  3. In an electric circuit, electrons are forced towards the positive terminal of a battery.
  4. Electric current is the amount of charge that passes a point in a circuit in each second.
  5. Current can be found using the equation: current = charge ÷ time.

Common misconception

Magnetic field effects are often mistaken for electric field effects.

Be explicit in teaching that electric charges and charged objects are not magnetic.

Keywords

  • Van de Graaff generator - A device that produces electric charge and is used in electrostatic experiments.

  • Charge - An electrical property; it can either be positive or negative.

  • Electric field - The invisible field around a charged object that causes another charged object to experience a force.

  • Coulomb - The unit of electric charge.

  • Ampere - The unit of electric current.

For some classes, it may be helpful to investigate the attraction or repulsion between positively and negatively charged rods. The charge on the dome of a Van de Graaff generator will depend on the material the rollers are made of. This lesson assumes the charge on the dome is negative.
Teacher tip

Equipment

Van de Graaff generator and discharge ball for demonstration.

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
An object becomes positively charged by friction. Which of the following explains how this happens?
It gains protons.
It gains electrons.
It loses protons.
Correct answer: It loses electrons.
Q2.
How many of the following types of particle can an object gain or lose when it is rubbed against another object: electrons, protons, neutrons?
none of them
Correct answer: one
two
three
Q3.
Which of the following statements about electric field lines are correct?
The arrows show the direction of force on a negative charge.
The arrows show the direction of force on a north-seeking pole.
The lengths of the field lines show the strength of the field.
Correct answer: The field is stronger where the lines are closer together.
Correct answer: The field lines around a spherical charge are radial.
Q4.
Which of the following statements about the arrows on electric field lines are correct?
They point towards a positively–charged object.
Correct answer: They point away from a positively–charged object.
Correct answer: They point towards a negatively–charged object.
They point away from a negatively–charged object.
Q5.
The diagram shows a Van de Graaff generator. After the generator is switched on, which of the following happen?
An image in a quiz
Part A moves and rubs against rollers.
Correct answer: Part B moves and rubs against rollers.
Correct answer: The part that builds up the largest charge is part A.
The part that builds up the largest charge is part B.
Q6.
Speed, distance and time are related by the equation: speed = distance ÷ time. Which of the following are correct rearrangements of this equation?
Correct answer: distance = speed × time
distance = speed ÷ time
Correct answer: time = distance ÷ speed
time = speed × distance
time = speed ÷ distance

6 Questions

Q1.
Which of the following is a definition of electric current?
the distance travelled by an electron in one second
the number of electrons that flow past a point each second
the time taken for one coulomb of charge to flow past a point
Correct answer: the number of coulombs of charge that flow past a point each second
Q2.
A battery makes a current flow in a circuit. Which of the following statements about the electric field in the circuit are correct?
There is an electric field around the wires only.
There is an electric field around the battery only.
Correct answer: There is an electric field around the battery and the wires.
Correct answer: The electric field exerts equal forces on all of the electrons in the wires.
The electric field exerts the greatest force on electrons nearest the battery.
Q3.
Which of the following statements is correct?
Correct answer: The charge on one electron is much less than one coulomb.
The charge on one electron is one coulomb.
The charge on one electron is much more than one coulomb.
Q4.
If 12 coulombs (C) of charge flows in 2 seconds (s), the current is amps (A).
Correct Answer: 6, 6A, 6 A, 6 amps, six
Q5.
A current of 6 A flows in a circuit. The amount of charge that flows past in 3 s is C.
Correct Answer: 18, 18C, 18 C, 18 coulombs, eighteen
Q6.
A current of 0.50 A flows in a circuit. The time taken for 12 C of charge to flow past a point in the circuit is s.
Correct Answer: 24, 24s, 24 s, 24 seconds, twenty-four