Question

to locate the north pole of an electromagnet, use the ______-hand rule.
a. right
b. left

Explanation:

Identify the standard rule for conventional current

To find the magnetic polarity of an electromagnet (solenoid) when using conventional current flow (from positive to negative), the standard physics convention is the right-hand rule. Wrapping the fingers of your right hand in the direction of the conventional current around the coil causes your thumb to point toward the north pole of the electromagnet.

Compare with electron flow convention

Using the Left-hand rule for electromagnets knowledge point

$$ \text{Left-hand rule} \implies \text{Electron flow direction} $$

While the left-hand rule is used for electron flow (from negative to positive), standard electrical and physics curricula default to conventional current unless specified otherwise, making the right-hand rule the primary standard.

Answer:

• a. right (Correct answer)
• b. left