a b c d

a

$\text{Angle of dip at equator } \delta = 0^o$ $\text{Angle of dip at poles } \delta = 90^o$ $\text{ Earths magnetic field at equator }B_e = B cos0^o = B$ $\text{ Earths magnetic field at poles }B_p = B sin90^o = B$ $\text{Ratio of magnetic field} \frac{B_e}{B_p} = 1 :1$