Question

State Ampere’s circuital law. Use this law to find magnetic field due to straight infinite current carrying wire. How are the magnetic field lines different from the electrostatic field lines?

Answer 1

Explanation:

refer the pic for answer

Answer 2

Ampere's circuital law says that the integral of magnetic field along any closed loop is equal to μ0 times the current enclosed in the loop.

• Consider an infinite long wire. Consider an circular loop of radius r such that the wire is at the center.
• $\int\limits^a_b {B} \, dl$ = μ0 I

• B 2πr =μ0 I
• B = (μ0 I)/ 2πr

• Electric field lines are divergent.

• Electric field lines does not come back to the starting point.
• Magnetic field lines can curl.
• Magnetic field lines come back to the starting point and can continue.