These are similar to one and two mark questions but you will be expected to write in more depth for three and four mark questions.
Describe and explain the magnetic field inside and around a solenoid when a current flows through it. [4 marks]
This question has been written by a Bitesize consultant as a suggestion to the type of questions that may appear in an exam paper.
Outside the solenoid, the fields from the individual coils cancel  to give a weaker field . Inside the solenoid, the fields from the individual coils add together  to form a very strong uniform magnetic field .
Remember to discuss the field inside and outside the solenoid separately. Describe the strength of the field and explain it in terms of the fields from the individual coils adding up or cancelling.
A power transmission wire hangs so that it is at right angles to the Earth's magnetic field. Although this magnetic field is constant, the cable experiences a changing force.
Explain why the force experienced by the cable changes. [4 marks]
An Edexcel question courtesy of Pearson Education Ltd.
The transmission wire carries an alternating current . The force is caused by this current, which varies in size and direction . The direction of this force depends on the direction of the current so the direction of the force also changes . The magnitude of this force depends on the magnitude of the current so the magnitude of the force also changes .
Remember that force is a vector so it has both a magnitude and a direction. You can get more marks by referring to the magnitude and direction separately.