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

Na food processing facility, a spherical container of inner radius r1 5 40 cm, outer radius r2 5 41 cm, and ther- mal conductivity k 5 1.5 w/m · k is used to store hot water and to keep it at 100°c at all times. to accomplish this, the outer surface of the container is wrapped with a 800-w electric strip heater and then insulated. the temperature of the inner surface of the container is observed to be nearly 120°c at all times. as- suming 10 percent of the heat generated in the heater is lost through the insulation, (a) express the differential equation and the boundary conditions for steady one-dimensional heat conduction through the container, (b) obtain a relation for the variation of temperature in the container material by solving the differential equation, and (c) evaluate the outer surface tempera- ture of the container. also determine how much water at 100°c this tank can supply steadily if the cold water enters at 20°c.

Wavelength, frequency, and energy are related. what happens to a wave as it’s wavelength gets shorter?

Apair of 10μf capacitors in a high-power laser are charged to 1.7 kv. a. what charge is stored in each capacitor? b. how much energy is stored in each capacitor?