KCET · Physics · Current Electricity
For a given electric current the drift velocity of conduction electrons in a copper wire is \(v_d\) and their mobility is \(\mu\). When the current is increased at constant temperature
- A \(v_d\) increases, \(\mu\) remains the same
- B \(v_d\) remains the same, \(\mu\) increases
- C \(v_d\) decreases, \(\mu\) remains the same
- D \(v_d\) remains the same, \(\mu\) decreases
Answer & Solution
Correct Answer
(A) \(v_d\) increases, \(\mu\) remains the same
Step-by-step Solution
Detailed explanation
We know that, mobility of electron,
\(\mu=\frac{e \tau}{m}\)
\(\Rightarrow \quad \mu \propto \tau \quad[\tau \rightarrow\) relaxation time \(]\)
Thus, for constant temperature, \(\mu\) remains the same.
Since, \(I=n e A v_d\)
\(\Rightarrow \quad v_d \propto I\)
Hence, when current is increased, then drift velocity \(\left(v_d\right)\) also increases.
\(\mu=\frac{e \tau}{m}\)
\(\Rightarrow \quad \mu \propto \tau \quad[\tau \rightarrow\) relaxation time \(]\)
Thus, for constant temperature, \(\mu\) remains the same.
Since, \(I=n e A v_d\)
\(\Rightarrow \quad v_d \propto I\)
Hence, when current is increased, then drift velocity \(\left(v_d\right)\) also increases.
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- The maximum range of a gun on horizontal plane is \(16 \mathrm{~km}\). If \(g=10 \mathrm{~ms}^{-2}\), then muzzle velocity of a shell isKCET 2021 Medium
- Two spheres carrying charges \( +6 \mu \mathrm{C} \) and \( +9 \mu \mathrm{C} \). separated by a distance \( \mathrm{d} \), experiences a
force of repulsion \( F \). When a charge of \( -3 \mu \mathrm{C} \) is given to both the sphere and kept at the same
distance as before, the new force of repulsion isKCET 2015 Medium - Two cells of emf \( E_{1} \) and \( E_{2} \) are joined in opposition (such that \( E_{1}>E_{2} \) ). If \( r_{1} \) and \( r_{2} \) be the internal resistance and \( R \) be the external resistance, then the terminal potential difference is
KCET 2015 Hard - When a potential difference of \(10^{3} \mathrm{~V}\) is applied between \(A\) and \(B\), a charge of \(0.75 \mathrm{mC}\) is value of \(\mathrm{C}\) is (in \(\mu \mathrm{F}\) )
KCET 2013 Medium - In the Rutherford's alpha scattering experiment, as the impact parameter increases, the scattering angle of the alpha particle.KCET 2023 Easy
- The maximum height attained by a projectile when thrown at an angle \(\theta\) with the horizontal is found to be half the horizontal range. Then \(\theta\) is equal toKCET 2007 Easy
More PYQs from KCET
- Gametophyte is the dominant phase in the life cycle ofKCET 2011 Easy
- In the manufacture of hydrogen from water gas \( \left(\mathrm{CO}+\mathrm{H}_{2}\right) \), which of the following is correct
statement?KCET 2017 Hard - A dipole moment \(p\) and moment of inertia \(I\) is placed in a uniform electric field \(\mathbf{E}\). If it is displaced slightly from its stable equilibrium position, the period of oscillation of dipole isKCET 2020 Easy
- In a polysaccharide, number of monosaccharides are linked byKCET 2016 Easy
- The order and degree of the differential equation \( \left[1+\left(\frac{d y}{d x}\right)^{2}+\sin \left(\frac{d y}{d x}\right)\right]^{\frac{3}{4}}=\frac{d^{2} y}{d x^{2}} \)KCET 2016 Easy
- An octahedral complex is formed when hybrid orbitals of the following type are involvedKCET 2008 Easy