A small current loop of area A=0.0005m2 and moment of inertia I=6.1e-07kgm^2 car
ID: 2064020 • Letter: A
Question
A small current loop of area A=0.0005m2 and moment of inertia I=6.1e-07kgm^2 carries a current i=0.0042A with its magnetic moment perpendicular to the Earth's magnetic field. The magnitude of the Earth's fild is B=4.2e-05T.What is the magnitude of the net torque T on the loop?
T = _____Nm
If the Earth's magnetic field points north and the loop's magnetic moment points west, the loop would rotate clockwise as seen from: (choose one)
below looking up
above looking down
the south looking north
the north looking south
What is the angular acceleration a of the loop?
a = _____ rad/s2?
Explanation / Answer
a)
m = i A = 0.0042 * 0.0005 = 0.0000021= 2.1e-6
= m B sin = 2.1e-6 * 4.2e-05 * 1 = 8.82 * 10^-11 N.m
b)
above looking down
c)
= /I = 8.82e-11/6.1e-07 = 1.45e-4 rad/s2