Page 480 - Basic Electrical Engineering

This law is also used to determine the magnetic field intensity, H around a
current-carrying conductor. According to Biot-Savart law, the magnetic field
intensity at a point P due to current flowing through an extremely small

element of length dl is

i. directly proportional to the current, I
ii. directly proportional to the length of the element, dl

Figure 5.6 Magnetic field around a current-carrying conductor

Figure 5.7 Biot-Savart law

iii. directly proportional to the sine of angle θ where θ is the angle between the direction of the
current and the line joining the element dl with the point P as shown in Fig. 5.7.