Question 17: The net magnetic flux through any closed surface is :
(1) Infinity
(2) Negative
(3) Zero
(4) Positive
Answer: Option (3)
Explanation:
According to Gauss’s law for magnetism, the net magnetic flux through any closed surface is always zero.
This is because magnetic monopoles do not exist, and magnetic field lines form closed continuous loops.
Hence, the number of magnetic field lines entering a closed surface is equal to
the number of field lines leaving it.
Mathematically, Gauss’s law for magnetism is expressed as
\oint \vec{B}\cdot d\vec{A}=0Therefore, the net magnetic flux through any closed surface is zero.
Thus, the correct answer is Option (3).