✓ Board-verified
Physics · 2023 · 2 marks
Current ElectricityDrift of Electrons and the Origin of Resistivity2 marksUnderstandvery short answer
CBSE 2023 · Region 5 · Set 1 · Q24
The potential difference applied across a given conductor is doubled. How will this affect (i) the mobility of electrons and (ii) the current density…
The potential difference applied across a given conductor is doubled. How will this affect (i) the mobility of electrons and (ii) the current density in the conductor? Justify your answers.
Marking-scheme solution
(i) Effect of potential difference on mobility of electron \(\displaystyle \left(\frac{1}{2}\right)\) Justification
(i) Effect of potential difference on current density
Justification
(i) No effect
\(\displaystyle \mu=\frac{\mathrm{v}_{d} l}{\mathrm{V}}=\frac{l}{\text { enAR }}=\) Constant
Alternatively: \(\displaystyle \mu=\frac{\mathrm{v}_{d}}{E}=\frac{e \tau}{m}=\) Constant(ii) As \(\displaystyle \mathrm{J} \alpha \mathrm{V}\), current density gets doubled
\[\mathrm{J}=\frac{I}{A}=\frac{\mathrm{V}}{R A}
\]
All Current Electricity questions2023 question paperNCERT solutions: Current ElectricityPractice Current Electricity →
More from Current Electricity
- A steady current flows through a metallic wire whose area of cross-section increases continuously from one end of the wire to the other. The…2023
- (i) Define mobility of electrons. Give its SI units. (ii) A steady current flows through a wire AB, as shown in the figure. What happens to the…2023
- What is the order of magnitude of drift velocity of electrons in a conductor? Deduce the relation between the current flowing through a conductor and…2026
- 'Current is a scalar quantity, although we represent current with an arrow.' Explain. Derive the balance condition of a Wheatstone Bridge.2026
- The number of electrons flowing through a conductor per second is 3 · 3 × 10^19. The current flowing through the conductor is:2023
- A student sets up the circuit as shown in the figure to find the value of unknown resistance X and records a set of readings of the voltmeter and the…2026
- Define current density and relaxation time. Derive an expression for resistivity of a conductor in terms of number density of charge carriers in the…2023
- A battery of e. m. f. 12 V and internal resistance 0.5 Ω is connected to a 9.5 Ω resistor through a key. The ratio of potential difference between…2025
CBSE Class 12 Physics past-paper question from the 2023 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.