A coil with 100 turns is wound on a toroidal core as shown in Figure 5.15. The core has an inner radius of 2 cm, an outer radius of 5 cm, and a thickness of 1 cm. The
core material has a uniform permeability of μ = 200 μ0 and saturates at a flux density
of 1.2 T.
A What is the inductance of the coil?
B How much current is required to bring the core to the start of saturation (i. e. so that
the material at the inner diameter of the core reaches a flux density of 1.2 T)?
C How much current is required to fully saturate the core (i. e. to make all of the material in the core have a flux density of at least 1.2 T)?

a high pressure system is a dense air mass that is usually cooler and drier than the surrounding air. a low pressure system is a less dense air mass that is usually wetter and warmer than the surrounding air.

in general, areas that experience high atmospheric pressure also experience fair weather. low pressure systems can cause the formation of clouds and storms. air usually flows from areas of high pressure to areas of low pressure..

the aurora is formed when charged particles emitted from the sun during a solar flare penetrate the earth's magnetic shield and collide with atoms and molecules in our atmosphere. these collisions result in countless little bursts of light, called photons, which make up the aurora.

auroras are generated by charged solar particles hitting molecules in earth's atmosphere. this usually happens in high latitudes, because our planet’s magnetic field tends to funnel these particles toward the poles. that’s why it can be experienced in northern ohio.