Vertically component of earth's magnetic field is BV=BH‌tan‌δ where, BH = horizontal component of earth's magnetic field δ=angle‌of‌dip Total intensity of earth's magnetic field B=√BH6+BV2 =√BH2+BH2[∵tan‌δ=tan‌45°=1]=√2BH =1.44×0.4×10−4T =5.656×10−5T =0.5×10−4T