The pulsar SGR1806-20 has a period T = 7.5 sec and a “spindown” rate of |Ṫ| = 10⁻¹¹. Estimate the maximum magnetic field strength |B| at the surface of this pulsar by assuming that the rotational kinetic energy (M = 3 × 10³⁰ kg and R = 10³ m) is dissipated by magnetic dipole radiation.