ELECTROMAGNETISM
4 marks · NormalA student wants to make the field of an electromagnet stronger.
Give two adjustments they can make to the coil, apart from increasing the current.
Describe and explain how adding a core to the coil would help.
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.
Show answer
(a) Increase the number of turns or use more coils; wind the coil tighter. · must show Increase number of turns, Wind coil tighter
(b) Adding a core made from soft iron increases the field strength because the iron becomes magnetised and adds to the field created by the coil. · must show Soft iron helps concentrate and strengthen the field
Common mistakes: Confusing number of coils with current; Mixing up properties of different core materials
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States increase number of turns.
B2 (a) · 1 mark · States wind coils tighter/more turns per length.
M1 (b) · 1 mark · Mentions iron/soft core improves field strength.
A1 (b) · 1 mark · Correct explanation: iron core is magnetically soft and increases effect.
Worked solution
(a) The student could increase the number of turns in the coil and wind the coil more tightly.
(b) Adding a soft iron core would make the magnet stronger because the iron becomes magnetised by the field of the coil and adds to the overall magnetic field.