GATE 2019 EC – Question 33
The radiation resistance of a small dipole current element of length $l$ at a frequency of 3 GHz is 3 ohms. If the length is changed by 1%, then the percentage change in the radiation resistance, rounded off to two decimal places, is ________ %.
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Correct answer: 2.00 to 2.02
Explanation
For a short dipole $R_{rad}\propto l^2$, so a 1% increase in length gives $1.01^2-1=2.01\%$ change.