Current Electricity · JEE Main previous year questions

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2024 66 questions

Q342024 · 4 Apr 2024 · Shift 2
1. A.
2. B.
3. C.
4. D.
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Answer: D
Q582024 · 4 Apr 2024 · Shift 2· Numerical answer
Two wires $A$ and $B$ are made up of the same material and have the same mass. Wire $A$ has radius of $2.0 mm$ and wire $B$ has radius of $4.0 mm$ . The resistance of wire $B$ is $2Ω$ . The resistance of wire $A$ is ________ $Ω$ .
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Answer: 32
Q382024 · 1 Feb 2024 · Shift 1
1. A. $3 V$
2. B. $10 V$
3. C. $5 V$
4. D. $0 V$
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Answer: D
Q392024 · 1 Feb 2024 · Shift 1
A galvanometer has a resistance of $50 Ω$ and it allows maximum current of $5 mA$ . It can be converted into voltmeter to measure up to $100 V$ by connecting in series a resistor of resistance :
1. A. $19500Ω$
2. B. $5975Ω$
3. C. $20050Ω$
4. D. $19950Ω$
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Answer: D
Q432024 · 1 Feb 2024 · Shift 1
The radius $(r)$ , length $(l)$ and resistance $(R)$ of a metal wire was measured in the laboratory as $r = (0.35 \pm 0.05) cm$ $R = (100 \pm 10) ohm$ $l = (15 \pm 0.2) cm$ The percentage error in resistivity of the material of the wire is :
1. A. $37.3%$
2. B. $25.6%$
3. C. $35.6%$
4. D. $39.9%$
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Answer: D
Q502024 · 1 Feb 2024 · Shift 1
1. A. $10 kΩ$
2. B. $10Ω$
3. C. $1 kΩ$
4. D. $\frac{3}{7} kΩ < R_{s} < \frac{3}{5} kΩ$
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Answer: D
Q512024 · 1 Feb 2024 · Shift 1· Numerical answer
A rectangular loop of sides $12 cm$ and $5 cm$ , with its sides parallel to the $x$ -axis and $y$ -axis respectively, moves with a velocity of $5 cm/s$ in the positive $x$ axis direction, in a space containing a variable magnetic field in the positive $z$ direction. The field has a gradient of $1 0^{- 3} T/cm$ along the negative $x$ direction and it is decreasing with time at the rate of $1 0^{- 3} T/s$ . If the resistance of the loop is $6 mΩ$ , the power dissipated by the loop as heat is ____ $\times 1 0^{- 9} W$ .
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Answer: 216
Q352024 · 1 Feb 2024 · Shift 2
1. A.1
2. B. $\frac{2}{3}$
3. C. $\frac{3}{2}$
4. D. $\frac{1}{2}$
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Answer: D
Q392024 · 1 Feb 2024 · Shift 2
In a metre-bridge when a resistance in the left gap is $2Ω$ and unknown resistance in the right gap, the balance length is found to be $40 cm$ . On shunting the unknown resistance with $2Ω$ , the balance length changes by :
1. A. $62.5 cm$
2. B. $22.5 cm$
3. C. $20 cm$
4. D. $65 cm$
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Answer: B
Q462024 · 1 Feb 2024 · Shift 2
1. A. $- 1 \times 1 0^{- 2}^{\circ} C^{- 1}$
2. B. $- 2 \times 1 0^{- 2}^{\circ} C^{- 1}$
3. C. $- 2.5 \times 1 0^{- 2}^{\circ} C^{- 1}$
4. D. $- 1.5 \times 1 0^{- 2}^{\circ} C^{- 1}$
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Answer: A
Q492024 · 1 Feb 2024 · Shift 2
In an ammeter, $5%$ of the main current passes through the galvanometer. If resistance of the galvanometer is $G$ , the resistance of ammeter will be :
1. A. $199 G$
2. B. $200 G$
3. C. $\frac{G}{20}$
4. D. $\frac{G}{199}$
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Answer: C
Q452024 · 31 Jan 2024 · Shift 1
Two conductors have the same resistances at $0^{\circ} C$ but their temperature coefficients of resistance are $α_{1}$ and $α_{2}$ . The respective temperature coefficients for their series and parallel combinations are :
1. A. $α_{1} + α_{2}, \frac{α _{1} α _{2}}{α _{1} + α _{2}}$
2. B. $\frac{α _{1} + α _{2}}{2}, \frac{α _{1} + α _{2}}{2}$
3. C. $α_{1} + α_{2}, \frac{α _{1} + α _{2}}{2}$
4. D. $\frac{α _{1} + α _{2}}{2}, α_{1} + α_{2}$
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Answer: B
Q462024 · 31 Jan 2024 · Shift 1
If the percentage errors in measuring the length and the diameter of a wire are $0.1%$ each. The percentage error in measuring its resistance will be:
1. A.0.144%
2. B.0.2%
3. C.0.1%
4. D.0.3%
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Answer: D
Q502024 · 31 Jan 2024 · Shift 1
1. A.AND
2. B.NOR
3. C.OR
4. D.NAND
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Answer: C
Q592024 · 31 Jan 2024 · Shift 1· Numerical answer
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Answer: 1
Q452024 · 31 Jan 2024 · Shift 2
The resistance per centimeter of a meter bridge wire is $r$ , with $X Ω$ resistance in left gap. Balancing length from left end is at $40 cm$ with $25Ω$ resistance in right gap. Now the wire is replaced by another wire of $2 r$ resistance per centimeter. The new balancing length for same settings will be at
1. A.10 cm
2. B.80 cm
3. C.40 cm
4. D.20 cm
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Answer: C
Q502024 · 31 Jan 2024 · Shift 2
1. A.
2. B.
3. C.
4. D.
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Answer: D
Q532024 · 31 Jan 2024 · Shift 2· Numerical answer
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Answer: 3
Q592024 · 31 Jan 2024 · Shift 2· Numerical answer
The magnetic flux $ϕ$ (in weber) linked with a closed circuit of resistance $8Ω$ varies with time (in seconds) as $ϕ = 5 t^{2} - 36 t + 1$ . The induced current in the circuit at $t = 2 s$ is ____ A.
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Answer: 2
Q332024 · 30 Jan 2024 · Shift 1
1. A. $7 V$
2. B. $44 V$
3. C. $22 V$
4. D. $15 V$
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Answer: A
Q362024 · 30 Jan 2024 · Shift 1
A series L.R circuit connected with an ac source $E = (25 sin 1000 t) V$ has a power factor of $\frac{1}{2}$ . If the source of emf is changed to $E = (20 sin 2000 t) V$ , the new power factor of the circuit will be :
1. A. $\frac{1}{3}$
2. B. $\frac{1}{2}$
3. C. $\frac{1}{5}$
4. D. $\frac{1}{7}$
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Answer: C
Q432024 · 30 Jan 2024 · Shift 1
1. A. $2 mV$
2. B. $4 V$
3. C. $0.5 V$
4. D. $12 mV$
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Answer: C
Q472024 · 30 Jan 2024 · Shift 1
An electric toaster has resistance of $60Ω$ at room temperature ( $2 7^{\circ} C$ ). 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 $α = 2 \times 1 0^{- 4} /^{\circ} C$ )
1. A. $1235^{\circ} C$
2. B. $1667^{\circ} C$
3. C. $694^{\circ} C$
4. D. $1694^{\circ} C$
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Answer: D
Q522024 · 30 Jan 2024 · Shift 1· Numerical answer
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Answer: 6
Q312024 · 29 Jan 2024 · Shift 1
The resistance $R = \frac{V}{I}$ where $V = (200 \pm 5) V$ and $I = (20 \pm 0.2) A$ , the percentage error in the measurement of R is :
1. A. $5.5%$
2. B. $3%$
3. C. $7%$
4. D. $3.5%$
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Answer: D