Which of the following statements is NOT true regarding an electromagnet?1 pointIts strength can be increased.Its magnetic properties are permanent.It works only when current flows in a conductor.It can be used to lift heavy loads.

Analyze the factors that affect the strength of an electromagnet.

Modern MRI machines use electricity to generate their magnetic fields inside a circular chamber instead of using permanent magnets. Which of the following would NOT increase the strength of the MRI field? A.Increased radius of the MRI chamberB.Increased power supplied to the MRI machineC.Decreased resistance of the MRI machineD.Increased current through the MRI machine

The figure shows a simple electromagnet made of a coil of insulated wire wrapped around an iron nail.When the switch closed, which of the following will make this electromagnet stronger? (i) increasing the number of coils(ii) adding more turns to the coil(iii) increasing the direct current flowing through the coil(iv) changing the direct current flowing through the coil to alternating current.*1 pointii, iiii, ii, iiiii onlyiii only

Which of the following statements are true? aMagnets need to be touching an object to exert a magnetic force on the object. bDecreasing the distance between an object and a magnet increases the magnetic force. cIncreasing the distance between an object and a magnet increases the magnetic force. dThe magnetic force begins at a certain distance and then stays constant. eAll statements are true.

State which of the following modifications to the design would increase the strength. A Use ac instead of de through the electromagnet B Use a longer, thicker core C Join the two poles of the electromagnet with an iron bar placed across them D Increase the number of turns on the electromagnet