A loop, made of straight edges has six corners at A(0, 0, 0), B(L, 0, 0), C(L, L, 0), D(0, L, 0), E(0, L, L) and F(0, 0, L). A magnetic field B=B0i^+k^ T is present in the region. The flux passing through the loop ABCDEFA (in that order) is:

1. B0L2 Wb

2. 2B0L2 Wb

3. \(\sqrt2\)B0L2 Wb

4. 4B0L2 Wb

(b) Hint: The flux passing through the loop depends on the area of the loop.
Step 1: Find the flux.
The magnetic flux linked with the surface of area A in a uniform magnetic field is given by;
             ϕ=B.A
           A=A1+A2=L2k^+L2i^
and    B=B0i^+k^ T
Now  ϕ=B.A=B0i^+k^.L2k^+L2i^
           =2B0L2 Wb