
A potential difference of V applied at the ends of a copper wire of length l and diameter d. On doubling only d drift velocity.
A. Becomes two times
B. Becomes half
C. Does not change
D. Becomes one fourth
Answer
164.4k+ views
Hint:First try to find the relation between the drift velocity, Length of the given copper wire and the diameter of the copper wire. If we get any relation that means drift velocity depends on these quantities and hence putting the values from the question we get the desired result.
Formula used:
Drift velocity:
${v_d} = \dfrac{V}{{\rho\, l\,n\,e}}$
Where, V is the potential difference applied at the ends of the given copper wire. $\rho $ is the resistivity. $l$ is the length of the given copper wire. $n$ is the number density of free electrons. $e$ is the charge of the electron.
Complete step by step solution:
Given information from the question:
Potential difference applied on the ends of the wire is $V$.
Length of the copper wire is $l$.
Diameter of the given copper wire is $d$.
We know that, the expression of drift velocity is given as follows:
${v_d} = \dfrac{V}{{\rho\, l\,n\,e}}$
Here in the formula for drift velocity length of the wire is present. But there is no diameter quantity in the formula. It means the drift velocity does not depend on the diameter of the given copper wire. So, doubling the diameter d has no effect on the drift velocity. Therefore, the drift velocity does not change on doubling the diameter of the copper wire.
Hence, the correct answer is option C.
Note: Here the diameter is get doubled and as the drift velocity does not depends on the diameter so it causes no change but if the length of the wire will get doubled then there will be change in the drift velocity as it depends on the length of the wire. Or any of the other quantities in the formula will also cause change.
Formula used:
Drift velocity:
${v_d} = \dfrac{V}{{\rho\, l\,n\,e}}$
Where, V is the potential difference applied at the ends of the given copper wire. $\rho $ is the resistivity. $l$ is the length of the given copper wire. $n$ is the number density of free electrons. $e$ is the charge of the electron.
Complete step by step solution:
Given information from the question:
Potential difference applied on the ends of the wire is $V$.
Length of the copper wire is $l$.
Diameter of the given copper wire is $d$.
We know that, the expression of drift velocity is given as follows:
${v_d} = \dfrac{V}{{\rho\, l\,n\,e}}$
Here in the formula for drift velocity length of the wire is present. But there is no diameter quantity in the formula. It means the drift velocity does not depend on the diameter of the given copper wire. So, doubling the diameter d has no effect on the drift velocity. Therefore, the drift velocity does not change on doubling the diameter of the copper wire.
Hence, the correct answer is option C.
Note: Here the diameter is get doubled and as the drift velocity does not depends on the diameter so it causes no change but if the length of the wire will get doubled then there will be change in the drift velocity as it depends on the length of the wire. Or any of the other quantities in the formula will also cause change.
Recently Updated Pages
Uniform Acceleration - Definition, Equation, Examples, and FAQs

JEE Main 2021 July 25 Shift 1 Question Paper with Answer Key

JEE Main 2021 July 22 Shift 2 Question Paper with Answer Key

JEE Atomic Structure and Chemical Bonding important Concepts and Tips

JEE Amino Acids and Peptides Important Concepts and Tips for Exam Preparation

JEE Electricity and Magnetism Important Concepts and Tips for Exam Preparation

Trending doubts
JEE Main 2025 Session 2: Application Form (Out), Exam Dates (Released), Eligibility, & More

Atomic Structure - Electrons, Protons, Neutrons and Atomic Models

Displacement-Time Graph and Velocity-Time Graph for JEE

JEE Main 2025: Derivation of Equation of Trajectory in Physics

Electric field due to uniformly charged sphere class 12 physics JEE_Main

Learn About Angle Of Deviation In Prism: JEE Main Physics 2025

Other Pages
JEE Advanced Marks vs Ranks 2025: Understanding Category-wise Qualifying Marks and Previous Year Cut-offs

JEE Advanced Weightage 2025 Chapter-Wise for Physics, Maths and Chemistry

Electric Field Due to Uniformly Charged Ring for JEE Main 2025 - Formula and Derivation

Degree of Dissociation and Its Formula With Solved Example for JEE

Wheatstone Bridge for JEE Main Physics 2025

Instantaneous Velocity - Formula based Examples for JEE
