# Question #93303

For simplicity let the loop be a square with sides of length L and with the left and right sides parallel to B. When you look at the top and bottom pieces, adding up $\int B \cdot \mathrm{dl}$ is zero because B and dl are perpendicular to each other. For one of the sides $\int B \cdot \mathrm{dl} = + B L$ since B and dl are in the same direction and for the other side $\int B \cdot \mathrm{dl} = - B L$ since B and dl are in opposite directions so when you add all the pieces together around the loop you get zero. It does not mean that B is zero.