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?

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.

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

so the second one is b

thanks

To determine the polarity of an electromagnet, you would use the second right-hand rule. This rule states that if you point your thumb in the direction of the current flow through the coils of the electromagnet, then the fingers of your right hand would wrap around the coils in the direction of the magnetic field created by the electromagnet. So the statement "The polarity of an electromagnet can be determined using the second right-hand rule" is true. Therefore, the correct answer to the first question is A: True.

When current passing through a conductor is increased, the strength of the magnetic field produced by the conductor also increases. This is governed by Ampere's law, which states that the magnetic field created by a current-carrying conductor is directly proportional to the current through the conductor. Therefore, the statement "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" is false. The correct answer to the second question is B: False.

The third-hand rule, as you mentioned, is not a commonly known rule. The first and second right-hand rules are typically used to determine the effect of magnetic fields on charged particles or current-carrying conductors. Therefore, the statement "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" is false. The correct answer to the third question is B: False.