Answer:
a magnet that retains its magnetic properties in the absence of an inducing field or current
Answer:
Option D is the correct answer
Explanation:
(I assume that the 4 directions north-south-east-west are meant with respect to the wire seen from the top.)
We can use the right-hand rule to understand the direction of the magnetic field generated by the wire. The thumb follows the direction of the current in the wire (upward), while the other fingers give the direction of the field in every point around the wire. Seen from the top, the field has an anti-clockwise direction. Therefore, if we take a point at east with respect to the wire, in this point the field has direction south.
For small deflections, T = 2*pi*sqrt(L / g) where T is period, L is length and g is gravity.
Setting the equations to the same period, 2*pi*sqrt(3.85 / g) = 2*pi*(L / (1/6 * g))
The equation reduces to 3.85 m = 6 * L so L = 0.642 m
chrsclrk · 7 years ago
