Question

The law used to find the direction of magnetic field lines is ____.
A) Right-hand thumb rule
B) Clasp rule
C) Both A and B
D) None of the above

Answer 1

Hint: We know that magnetic field lines are the visual representation of magnetic fields. They show the direction of the magnetic force on the poles. We also know that magnetic field lines move from north pole to south pole. Now, to study the nature of their direction, we have to use some rules.

Complete step by step solution:
To solve this question, let us take all the options one by one and then analyze them.

Option A: As discussed above, according to the Biot-Savart law, if the thumb of the right hand is placed in the direction of the current flow, then the finger curls will give the direction of the magnetic field. So, the right-hand thumb rule is used to find the direction of the magnetic field lines.
Hence, it is the correct option.

Option B: Now, we know that that clasp rule is the other name of the right-hand thumb rule. As, it states that when a conductor is grasped in the right hand with the thumb pointing towards the direction of the current, then the curls of fingers will show the direction of the magnetic field.
Hence, this option is also correct.

Option C: Now, as we have discussed above option A and option B are both correct. So, this option is the correct answer.
Hence, this option is the correct answer.

Option D: As we have discussed above, option A and option B are both correct, which means option C is the correct answer.

So, the correct answer is option (C).

Note: We know that right hand thumb is the most accurate rule to find the direction of the magnetic field lines. Now, we also know that the right hand thumb rule has another name that is clasp rule. Hence, these both rules state the same thing and can be used to find the direction of the magnetic field lines.