SSC JE Electrical Engineering 22 Jan 2018 Morning Paper

Question : 188 of 200

Marks: +1, -0

The depth of penetration, in the case hardening of a steel pulley, required is 105 mm. The relative permeability is unity and the specific resistance for steel is 5 × 10

^{–7}

Ω-m. Determine the frequency required.

56.3 KHz
46.7 KHz
52.7 KHz
58.6 KHz

Validate

Solution:

Given data

µ_r=1

µ_0=4π×10^{-7}\H\/m

ρ=5×10^{-7}\Ω-\m

Skin depth is given by

S=√{2/{ωµσ}}

∴S=√{{2ρ }/{2πfµ_0µ_r}}

⇒0.105=√{{5×10^{-7}}/{π×4π×10^{-7}}}

∴ f = 11.48Hz

Go to Question:

Prev Question

Next Question