Free physics question bank
electric current ,current density and resistance questions with solutions
Practice Current electricity for JEE Main, JEE Advanced, NEET, and Classes 11–12. Attempt each question, then open it for the full solution.
Showing 1–10 of 26 questions
- Multi-correctdifficultCurrent electricity
An electric bulb has a solid cylindrical filament of length l and radius r and it consumes power P when connected to a power source. Another bulb having cylindrical filament of same material, operating at same voltage and emitting the same spectrum of light consumes 8P power. Find length and radius of the new filament. Assume that the filaments do not radiate from the flat ends and radiation is the only source of heat loss from the filaments.
Select all that apply
Current Electricity Objective Conversion
Open question & full solution → - MCQdifficultCurrent electricity
A conductor having resistivity ρ is bent in the shape of a half cylinder as shown in the figure. The inner and outer radii of the cylinder are a and b respectively and the height of the cylinder is h. A potential difference is applied across the two rectangular faces of the conductor. Calculate the resistance offered by the conductor.
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Current Electricity Objective Conversion
Open question & full solution → - NumericeasyCurrent electricity
Resistance of a wire at 0°C, 100°C and t°C is found to be 10 Ω, 10.2 Ω and 10.95 Ω respectively. The temperature t in Kelvin scale is______.
JEE Mains 2024 08 Apr Morning Shift
Open question & full solution → - MCQeasyCurrent electricity
The resistance of a wire is 5 Ω. Its new resistance in ohm if stretched to 5 times of its original length will be :
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JEE Mains25 January 2023Shift 2Evening Shift
Open question & full solution → - MCQmediumCurrent electricity
Two conductors have the same resistances at 0°C but their temperature coefficients of resistance are α₁ and α₂. The respective temperature coefficients for their series and parallel combinations are:
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JEE Mains 2024 31 Jan Morning Shift
Open question & full solution → - NumericmediumCurrent electricity
A cylindrical conductor of length 2m and area of cross-section 0.2 mm² carries an electric current of 1.6 A when its ends are connected to a 2V battery. Mobility of electrons in the conductor is α × 10⁻³ m²/V.s. The value of α is :
(electron concentration = 5 × 10²⁸/m³ and electron charge = 1.6 × 10⁻¹⁹ C)
JEE Mains 202622 January Evening Shift
Open question & full solution → - IntegermediumCurrent electricity
The current through a conductor at 0°C and 100°C, for the same voltage source, is 2 A and 1.2 A respectively. The current at 50°C is ______ × 10² mA.
JEE Mains12 April 2023Shift 1Morning Shift
Open question & full solution → - NumericdifficultCurrent electricity
A copper wire of length 5 cm carries a current of density j = 1 A(mm)⁻². The density and molar mass of copper are 9000 kg m⁻³ and 63 g mol⁻¹. Each copper atom contributes one free electron. The temperature of the wire is 27°C. Estimate the (average) distance travelled by a free electron during the time it moves from one end of the copper wire to the other end. Assume that thermal motion of electrons are similar to that of molecules of an ideal gas. Give the answer in kilometres, rounded to nearest integer.
Current Electricity Objective Conversion
Open question & full solution → - MCQeasyCurrent electricity
Which of the four graphs shown in the original question correctly represents the variation of resistivity ρ with temperature T for a conductor?
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JEE Main 2025 (Online) 22 jan morning Shift
Open question & full solution → - MCQmediumCurrent electricity
An electric toaster has resistance of 60 Ω at room temperature (27ºC). The toaster is connected to a 220 V supply. If the current flowing through it reaches 2.75 A, the temperature attained by toaster is around : (if α = 2 × 10⁻⁴ /ºC)
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JEE Mains 2024 30 Jan Morning Shift
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