Magnetism and Electromagnetism
5 marks · NormalThe diagrams below show the magnetic field around a straight wire and a solenoid carrying a current.
Draw the magnetic field lines around a straight wire carrying current.
Explain how the right-hand grip rule can be used to determine the direction of these field lines.
Describe one way to increase the strength of the magnetic field around a solenoid.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) — · must show Wire with circular field lines centered around, arrow for direction
(b) Point your right thumb in the direction of the current; your fingers curl in the direction of the magnetic field lines around the wire. · must show right-hand, thumb=current, fingers=field direction
(c) Increase the current / add more turns / insert an iron core.
Must show: correct diagram
Common mistakes: using left hand
Show mark scheme and worked solution
Marking points
B4a (a) · 2 marks · Circular field lines centred on wire (1); arrow showing correct direction (1).
B4b (b) · 2 marks · Clear, accurate use of right-hand grip rule: thumb for current, fingers for field direction (2).
B4c (c) · 1 mark · States a valid method to increase field strength (1).
Worked solution
b) To find the field direction: point your right thumb in the direction of current, and your curled fingers show the field direction around the wire.
c) One way to increase the field strength around a solenoid is to insert an iron core or increase the current.