In a sunspot the plasma temperature is approximately 4000 K (compared to the average photospheric temperature of 6000 K)

[answerhappygod]

In a sunspot the plasma temperature is approximately 4000 K
(compared to the average photospheric temperature of 6000 K). If
the magnetic field is 0.3 T inside the sunspot and close to zero
outside of it, and the particle density is 2.1. 1019 cm-3 outside
of the sunspot; determine the ratio of particle densities inside
and outside of the sunspot, using pressure balance.