What causes an aurora?
O A. An aurora is the consequence of solar wind entering the Earth and cutting through the Earth's magnetosphere.
OB. An aurora is the consequence of combustion of gases taking place at the poles of the Earth.
Oc. An aurora is the consequence of solar prominences entering the Earth.
OD. An aurora is the consequence of Sunspots entering the Earth.

An insulated 40 ft^3 rigid tank contains air at 50 psia and 120°f. a valve connected to the tank is now opened, and air is allowed to escape until the pressure inside drops to 25 psia. the air temperature during this process is kept constant by an electric resistance heater placed in the tank. determine the electrical work done during this process.

Aloop of wire is in a magnetic field such that its axis is parallel with the field direction. which of the following would result in an induced emf in the loop? choose all that apply. a loop of wire is in a magnetic field such that its axis is parallel with the field direction. which of the following would result in an induced emf in the loop? choose all that apply. moving the loop outside of the magnetic field region. spin the loop such that its axis does not consistently line up with the magnetic field direction. change the magnitude of the magnetic field. change the diameter of the loop

A51 kg woman skis down a hill and her kinetic energy is 9.96e4 j. what is her speed?