HOTS Questions with Answer: Magnetic Effects of Electric Currents Q1.On what factors does the magnetic field intensity at the centre of the circular coil carrying current depend ? Answer: The magnetic field intensity at the centre of the circular coil is directly proportional to current and inversely proportional to radius of the coil. So, in both the cases ,that is, twice the current as well as half in radius, the magnetic field intensity gets doubled. The magnitude of the magnetic field (B) at the of the coil is: (i). directly proportional to the current (I) flowing it. i.e. B α I ① (ii). Inversely proportional to the radius (r) of the coil i.e. B α 1/r ...