Given below are two statements: Statement I : According to Biot-Savart's law, the magnitude of the magnetic field produced by a current element is inversely proportional to the cube of the distance between the element and the observation point. Statement II : The direction of the magnetic field d B produced by a current element I d l is always perpendicular to the plane containing the current element and the position

Step-by-step solution

According to Biot-Savart's law, the magnetic field due to a current element is given by d B = ₀ 4 I d l r r^3 . The magnitude of the magnetic field is dB = ₀ 4 I dl r^2 . This shows that the magnitude of the magnetic field is inversely proportional to the square of the distance r , not the cube. Hence, Statement I is incorrect. The direction of d B is determined by the cross product d l r . By the properties of the cross product, d B is perpendicular to both d l and r , which means it is perpendicular to the plane