RE-NEET 2024 Physics Drift Velocity MCQ Question
A uniform wire of diameter d carries a current of 100 mA when the mean drift velocity of electrons in the wire is v. For a wire of diameter d/2 of the same material to carry a current of 200 mA, the mean drift velocity of electrons in the wire is
4v
8v
v
2v
Correct Answer
Detailed Explanation
The drift velocity v is proportional to the current I and inversely proportional to the cross-sectional area A (v ∝ I/A). Halving the diameter reduces A by a factor of 4, so to maintain the same current density, the drift velocity must increase by a factor of 8.
Found an issue with this question?
Related Questions
More from 2024
Which of the following factors are favourable for the formation of oxyhaemoglobin in alveoli?
On heating, some solid substances change from solid to vapour state without passing through liquid state. The technique used for the purification of s...
The rate of a reaction quadruples when temperature changes from 27°C to 57°C. Calculate the energy of activation. Given R = 8.314 J K⁻¹ mol⁻¹, log 4 =...