Given, Horizontal component of earth's magnetic field =0.25×10−4Wb∕m2 Vertical component of earth's magnetic field =0.35×10−4Wb∕m2 The earth's total magnetic field =√H2+V2 =√(0.25×10−4)2+(0.35×10−4)2 =10−4√0.0625+0.1225 =0.43×10−4Wb∕m2