Question

The polarity of an electromagnet can be determined using the second right-hand rule.
A. True
B. False
Is it B?

Current passing through a conductor is increased from 10 A to 15 A. This decreases the strength of the magnetic field produced by the conductor.
A. True
B. False
Is it a?

The direction of the force on doubly ionized helium atoms (alpha particles) moving at right angles to a magnetic field is opposite to the direction of force given by the third-hand rule.
A. True
B. False
Is it a?

Answer 1

I use a right hand rule for A, but I dontknow what your "second right hand rule" is.

Increasing current increases B.

I don't know what the "third hand rule " is.

Answer 2

there are four right hand rules, I will re-read it

so the second one is b

thanks