Physic question: The magnetic field?

Question

Question:
The magnetic field perpendicular to a loop of wire 20cm in diameter is changed from
+0.52T to -0.45T in 180ms, where + means the field points away from an observer and – toward the observer

1. calculate the induced emf

2. in what direction does the induced current flow?

Answer 1

This appears to be a straightforward application of Faraday's law:

V = -n*d(phi)/d(t)

where:
V = voltage
n = number of turns in coil
phi = magnetic flux density
t = time

n = 1 for this problem
d(phi)/d(t) = (0.52 - (-0.45))/0.180 = 5.3889

So, I would expect -5.3889 volts (because of the -n)
Because the flow is now toward the observer, I would say that the current would flow counter-clockwise, based on the right hand rule.

Wait for other answers. I'm not 100% sure on this one

Answer 2

Dogsafire is right except that the change in B is negative which cancels out the negative and makes v positive
and the direction is clockwise because the loop tries to make up for the loss in magnetic field

Answer 3

while utilising facebook=qv bypass B, undergo in techniques q is unfavourable for an electron. For sensible purposes in this question, you may enable for this by ability of treating v as no count if it is interior the -i direction. There are distinctive rules - for example you're you able to Fleming's Left hand rule for this or a suited hand bypass-product rule yet while A = B bypass C and you recognize A and (say) B, you may paintings out C while you're careful. (and you will continually examine your answer by ability of testing that A and B then supply the common direction of A.)