What causes a magnetic field to form around certain metals, such as iron?
a. the majority of the domains are aligned.
b. the majority of the protons are aligned.
c. the majority of non-metal atoms are aligned.
d. the majority of the atoms have been acted upon by gravity.

The frequencies refer to the sample data collected from a population of interest when performing a hypothesis test comparing two or more population proportions.

What property of an object determines its inertia?

Two charged particles, q1 and q2, are located on the x-axis, with q1 at the origin and q2 initially at x1 = 12.2 mm. in this configuration, q1 exerts a repulsive force of 2.62 µn on q2. particle q2 is then moved to x2 = 18.0 mm. what is the force (magnitude and direction) that q2 exerts on q1 at this new location? (give the magnitude in µn.)