Posted by J on Monday, March 3, 2008 at 6:44pm.
If a magnetic flux passes through a circular coil when its diameter D, what should be its diameter (in terms of D) so that only half as much flux passes through it in the same field? Assume that the magnetic field is uniform over the area in both cases.
I am totally lost! I Don't know where to start!

Physics  Damon, Monday, March 3, 2008 at 6:54pm
the area should be half the original
Area = pi r^2 = pi D^2/4
new area = pi D^2/8 = pi Dnew^2/4
Dnew ^2 = (1/2) D^2
Dnew = .707 D 
Physics  J, Monday, March 3, 2008 at 7:22pm
ok I am confused, because I have the answer in the back of my book it says it is D/square root of 2