During induction heating, the skin depth of penetration is proportional (f = frequency) to
Right Answer is:
In induction heating, the heat in the electrically conducting workpiece is produced by circulating currents caused by electromagnetic induction. Induction heating is clean quick and efficient. It allows a defined section of the workplace to be heated accurately.
The depth to which the heated zone extends depends on the frequency of the current and on the duration of the heating cycle. Because of an electrical phenomenon called the “skin effect,” the penetration depth of the heated area is inversely proportional to the square root of frequency and directly proportional to the square root of the workplace resistivity p
δ = K.√ρ/√f
Where K is constant
Therefore, the induction frequency is selected based on the application. A low frequency such as the utility frequency may be used for induction melting of large workpieces. High frequencies of up to a few hundred kilohertz are used for forging, soldering, hardening, and annealing.