Astrophysics Question Using that the pressure of the sunspot

Astrophysics Question. Using that the pressure of the sunspot(ideal gas) plus the magnetic pressure B^2/2(mew-knot) equals the photosphere pressure in order for the sunspot to sink. Use that p= 3.5x10^-4 kg/m^3 and (mew = 1) to find the magnetic field in the sunspot.

Solution

p_gas +p_magnetic = p_surface

pmagnetic = 6.08*10^-3(from the chart)-3.5*10^-4

B^2/2 = 5.73*10^-3

B = 1.07 *10^-2 T