Magnets Flashcards
Which way do all magnetic field lines point
North to South
Likes poles…
repel
opposite poles…
attract
What causes a magnetic field around a wire
current flowing through it
What is an electromagnet made from
A current carrying wire called a solenoid
Three ways in which you can increase the magnetic field strength of an electromagnet:
- More current through the wire
- More coils of wire per unit length
- Use a core of soft iron
Three uses of an electromagnet:
Electric bell, scrap heap crane, speakers,
Where on a bar magnet is there high magnetic flux density?
At the poles
What are the three magnetic elements at room temperature?
Iron (Fe), Nickel (Ni), Cobalt (Co)
Three facts about magnetic field lines:
- They never cross
- They flow North to South
- The closer they are the stronger the magnetic filed.
What element is the Earth’s core?
Iron
Where on the Earth is magnetic field strength eat its weakest?
The Equator
What does the Earth’s magnetic field protect us from?
The sun
What is the difference between a ‘soft’ and a ‘hard’ magnetic core?
The hard magnetic core is always magnetic whereas the soft magnetic core can magnetised and demagnetised
Give the symbol for Current
I
