Electronic Devices and Circuits - Engineering

Q1:

The resistance of a metallic wire would

A increase as the operating frequency increase

B decrease as the operating frequency increase

C remain unaffected on increasing the operating frequency

D first increase then decrease

ANS:B - decrease as the operating frequency increase

The correct answer is A.

To prove it mathematically, resistance is equal to the resistivity times the length all over the area.

At high frequencies, skin effect occurs, decreasing the effective area.

Dividing by a smaller area gives us a greater resistance.