Current Electricity · JEE Main previous year questions

429 questions asked across 20 exam years, newest first

Year-wise papers Topic-wise questions

Practise this topic

2021 49 questions

Q402021 · 18 Mar 2021 · Shift 1
In the experiment of Ohm's law, a potential difference of 5.0 V is applied across the end of a conductor of length 10.0 cm and diameter of 5.00 mm. The measured current in the conductor is 2.00 A. The maximum permissible percentage error in the resistivity of the conductor is :
1. A.3.9
2. B.8.4
3. C.7.5
4. D.3.0
Show answer
Answer: A
Q412021 · 18 Mar 2021 · Shift 1
In a series LCR resonance circuit, if we change the resistance only, from a lower to higher value :
1. A.The bandwidth of resonance circuit will increase.
2. B.The resonance frequency will increase.
3. C.The quality factor will increase.
4. D.The quality factor and the resonance frequency will remain constant.
Show answer
Answer: A
Q422021 · 18 Mar 2021 · Shift 1
An AC source rated 220 V, 50 Hz is connected to a resistor. The time taken by the current to change from its maximum to the rms value is :
1. A.2.5 ms
2. B.25 ms
3. C.2.5 s
4. D.0.25 ms
Show answer
Answer: A
Q532021 · 18 Mar 2021 · Shift 1· Numerical answer
Show answer
Answer: 70
Q602021 · 18 Mar 2021 · Shift 1· Numerical answer
An npn transistor operates as a common emitter amplifier with a power gain of $1 0^{6}$ . The input circuit resistance is $100Ω$ and the output load resistance is $10 K Ω$ . The common emitter current gain ' $β$ ' will be _______. (Round off to the Nearest Integer).
Show answer
Answer: 100
Q412021 · 18 Mar 2021 · Shift 2
The time taken for the magnetic energy to reach 25% of its maximum value, when a solenoid of resistance R, inductance L is connected to a battery, is :
1. A.infinite
2. B. $\frac{L}{R} ln 10$
3. C. $\frac{L}{R} ln 2$
4. D. $\frac{L}{R} ln 5$
Show answer
Answer: C
Q512021 · 18 Mar 2021 · Shift 2· Numerical answer
Two wires of same length and thickness having specific resistances $6 Ω cm$ and $3 Ω cm$ respectively are connected in parallel. The effective resistivity is $ρ Ω cm$ . The value of $ρ$ , to the nearest integer, is ____.
Show answer
Answer: 4
Q522021 · 18 Mar 2021 · Shift 2· Numerical answer
Show answer
Answer: 48
Q572021 · 18 Mar 2021 · Shift 2· Numerical answer
Show answer
Answer: 5
Q422021 · 16 Mar 2021 · Shift 1
A conducting wire of length 'l', area of cross-section A and electric resistivity $ρ$ is connected between the terminals of a battery. A potential difference V is developed between its ends, causing an electric current. If the length of the wire of the same material is doubled and the area of cross-section is halved, the resultant current would be :
1. A. $4 \frac{V A}{ρl}$
2. B. $\frac{3}{4} \frac{V A}{ρl}$
3. C. $\frac{1}{4} \frac{V A}{ρl}$
4. D. $\frac{1}{4} \frac{ρl}{V A}$
Show answer
Answer: C
Q452021 · 16 Mar 2021 · Shift 1
1. A.
2. B.
3. C.
4. D.
Show answer
Answer: D
Q532021 · 16 Mar 2021 · Shift 1· Numerical answer
Show answer
Answer: 3
Q552021 · 16 Mar 2021 · Shift 1· Numerical answer
The resistance $R = \frac{V}{I}$ , where $V = (50 \pm 2) V$ and $I = (20 \pm 0.2) A$ . The percentage error in R is 'x'%. The value of 'x' to the nearest integer is _________.
Show answer
Answer: 5
Q572021 · 16 Mar 2021 · Shift 1· Numerical answer
Show answer
Answer: 0
Q422021 · 26 Feb 2021 · Shift 1
1. A. $\frac{θ _{1} R _{2} + θ _{2} R _{1}}{R _{1} + R _{2}}$
2. B. $\frac{θ _{1} R _{1} + θ _{2} R _{2}}{R _{1} + R _{2}}$
3. C. $\frac{θ _{1} R _{2} - θ _{2} R _{1}}{R _{2} - R _{1}}$
4. D. $\frac{θ _{2} R _{2} - θ _{1} R _{1}}{R _{2} - R _{1}}$
Show answer
Answer: A
Q502021 · 26 Feb 2021 · Shift 1
1. A. $\frac{3 R}{2}$
2. B. $\frac{R}{2}$
3. C. $2 R$
4. D. $R$
Show answer
Answer: D
Q522021 · 26 Feb 2021 · Shift 1· Numerical answer
Show answer
Answer: 20
Q542021 · 26 Feb 2021 · Shift 1· Numerical answer
In an electrical circuit, a battery is connected to pass 20C of charge through it in a certain given time. The potential difference between two plates of the battery is maintained at 15V. The workdone by the battery is __________J.
Show answer
Answer: 300
Q592021 · 26 Feb 2021 · Shift 1· Numerical answer
In a series LCR resonant circuit, the quality factor is measured as 100. If the inductance is increased by two fold and resistance is decreased by two fold, then the quality factor after this change will be __________.
Show answer
Answer: 283
Q322021 · 26 Feb 2021 · Shift 2
An aeroplane, with its wings spread 10 m, is flying at a speed of 180 km/h in a horizontal direction. The total intensity of earth's field at that part is $2.5 \times 1 0^{- 4} Wb/ m^{2}$ and the angle of dip is $6 0^{\circ}$ . The emf induced between the tips of the plane wings will be _________.
1. A.88.37 mV
2. B.62.50 mV
3. C.54.125 mV
4. D.108.25 mV
Show answer
Answer: D
Q332021 · 26 Feb 2021 · Shift 2
1. A.2 A and 100 Hz
2. B.2 A and 50 Hz
3. C.0.2 A and 100 Hz
4. D.0.2 A and 50 Hz
Show answer
Answer: D
Q382021 · 26 Feb 2021 · Shift 2
A wire of $1Ω$ has a length of 1 m. It is stretched till its length increases by 25%. The percentage change in resistance to the nearest integer is :
1. A.76%
2. B.12.5%
3. C.25%
4. D.56%
Show answer
Answer: D
Q472021 · 25 Feb 2021 · Shift 2
1. A.
2. B.
3. C.
4. D.
Show answer
Answer: D
Q592021 · 25 Feb 2021 · Shift 2· Numerical answer
Show answer
Answer: 2