Suppose the field inside a large piece of magnetic material is b0, so that h0 = (1/μ0)b0 − m, where m is a "frozen-in" magnetization. (a) now a small spherical cavity is hollowed out of the material (fig. 6.21). find the field at the center of the cavity, in terms of b0 and m. also find h at the center of the cavity, in terms of h0 and m. (b) do the same for a long needle-shaped cavity running parallel to m. (c) do the same for a thin wafer-shaped cavity perpendicular to m.

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.

The diagram shows the positions of the sun, moon and earth during spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

Which atom or ion is the largest? 0 a. 0 0 0 0 e. li