a solenoid having 200 turns per metre and carrying a current of 0.050A lies with its axis east west. Well inside the solenoid is a small compass whose needle points 37 west of north. calculate earth's horizontal magnetic field component B i already find the magnetic flux density of solenoid which is 1.26 X 10^-5 T. what should i do next? and is there any site that have a good explanation on earth's horizontal magnetic field. it is not covered in my syllabus, but i just want to know.