Current Electricity · JEE Main previous year questions

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2019 39 questions

Q442019 · 12 Apr 2019 · Shift 1
1. A.
2. B.
3. C.
4. D.
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Answer: C
Q452019 · 12 Apr 2019 · Shift 1
1. A.
2. B.
3. C.
4. D.
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Answer: C
Q462019 · 12 Apr 2019 · Shift 1
1. A. $115 μ A$
2. B. $170 μ A$
3. C. $60 μ A$
4. D. $150 μ A$
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Answer: B
Q502019 · 12 Apr 2019 · Shift 1
1. A.The value of the resistance R is $1.5 Ω$
2. B.The emf of the battery is 1.5 V and its internal resistance is $1.5 Ω$
3. C.The emf of the battery is 1.5 V and the value of R is $1.5 Ω$
4. D.The potential difference across the battery is 1.5 V when it sends a current of 1000 mA
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Answer: B
Q592019 · 12 Apr 2019 · Shift 1
1. A. $5 \times 1 0^{4}$ , $5 \times 1 0^{5}$
2. B. $5 \times 1 0^{4}$ , $5 \times 1 0^{6}$
3. C. $5 \times 1 0^{4}$ , $2.5 \times 1 0^{6}$
4. D. $2.5 \times 1 0^{4}$ , $2.5 \times 1 0^{6}$
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Answer: C
Q372019 · 12 Apr 2019 · Shift 2
1. A. $\frac{2.7 E L}{R ^{2}}$
2. B. $\frac{E L}{2.7 R ^{2}}$
3. C. $\frac{7.3 E L}{R ^{2}}$
4. D. $\frac{E L}{7.3 R ^{2}}$
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Answer: B
Q442019 · 12 Apr 2019 · Shift 2
A moving coil galvanometer, having a resistance G, produces full scale deflection when a current Ig flows through it. This galvanometer can be converted into (i) an ammeter of range 0 to $I_{0} (I_{0} > I_{g})$ by connecting a shunt resistance $R_{A}$ to it and (ii) into a voltmeter of range 0 to V $(V = G I_{0})$ by connecting a series resistance $R_{V}$ to it. Then,
1. A. $R_{A} R_{V} = G^{2}$ and $\frac{R _{A}}{R _{V}} = \frac{I _{g}}{( I _{0} - I _{g} )}$
2. B. $R_{A} R_{V} = G^{2} (\frac{I _{g}}{I _{0} - I _{g}})$ and $\frac{R _{A}}{R _{V}} = (\frac{I _{0} - I _{g}}{I _{g}})^{2}$
3. C. $R_{A} R_{V} = G^{2} (\frac{I _{0} - I _{g}}{I _{g}})$ and $\frac{R _{A}}{R _{V}} = (\frac{I _{g}}{I _{0} - I _{g}})^{2}$
4. D. $R_{A} R_{V} = G^{2}$ and $\frac{R _{A}}{R _{V}} = (\frac{I _{g}}{I _{0} - I _{g}})^{2}$
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Answer: D
Q322019 · 10 Apr 2019 · Shift 1
A current of 5 A passes through a copper conductor (resistivity $= 1.7 \times 1 0^{- 8} Ω m$ ) of radius of cross-section 5 mm. Find the mobility of the charges if their drift velocity is $1.1 \times 1 0^{- 3} m/s$ .
1. A. $1.3 m^{2} /Vs$
2. B. $1.0 m^{2} /Vs$
3. C. $1.8 m^{2} /Vs$
4. D. $1.5 m^{2} /Vs$
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Answer: B
Q332019 · 10 Apr 2019 · Shift 1
1. A.4
2. B.3
3. C.2
4. D.1
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Answer: A
Q432019 · 10 Apr 2019 · Shift 1
1. A. $R (T) = R_{0} e^{- T^{2} / T_{0}^{2}}$
2. B. $R (T) = \frac{R _{0}}{T ^{2}}$
3. C. $R (T) = R_{0} e^{T^{2} / T_{0}^{2}}$
4. D. $R (T) = R_{0} e^{- T_{0}^{2} / T^{2}}$
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Answer: D
Q472019 · 10 Apr 2019 · Shift 1
A moving coil galvanometer allows a full scale current of $1 0^{- 4} A$ . A series resistance of $2 MΩ$ is required to convert the above galvanometer into a voltmeter of range 0-5 V. Therefore the value of shunt resistance required to convert the above galvanometer into an ammeter of range 0-10 mA is :
1. A. $200 Ω$
2. B. $500 Ω$
3. C. $100 Ω$
4. D.None of the options are correct
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Answer: D
Q482019 · 10 Apr 2019 · Shift 1
1. A. $1.5 Ω$
2. B. $1 Ω$
3. C. $0.5 Ω$
4. D. $0 Ω$
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Answer: C
Q332019 · 10 Apr 2019 · Shift 2
1. A.0.5 mA; 8.5 mA
2. B.1.5 mA; 8.5 mA
3. C.1 mA; 8.5 mA
4. D.0.5 mA; 6 mA
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Answer: A
Q342019 · 10 Apr 2019 · Shift 2
A bullet of mass 20 g has an initial speed of $1 m s^{- 1}$ , just before it starts penetrating a mud wall of thickness 20 cm. If the wall offers a mean resistance of $2.5 \times 1 0^{- 2} N$ , the speed of the bullet after emerging from the other side of the wall is close to :
1. A. $0.3 m s^{- 1}$
2. B. $0.1 m s^{- 1}$
3. C. $0.7 m s^{- 1}$
4. D. $0.4 m s^{- 1}$
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Answer: C
Q352019 · 10 Apr 2019 · Shift 2
A coil of self inductance 10 mH and resistance $0.1 Ω$ is connected through a switch to a battery of internal resistance $0.9 Ω$ . After the switch is closed, the time taken for the current to attain 80% of the saturation value is: [take ln 5 = 1.6]
1. A.0.324 s
2. B.0.002 s
3. C.0.103 s
4. D.0.016 s
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Answer: D
Q372019 · 10 Apr 2019 · Shift 2
Space between two concentric conducting spheres of radii a and b (b > a) is filled with a medium of resistivity $ρ$ . The resistance between the two spheres will be :
1. A. $\frac{ρ}{2 π} (\frac{1}{a} + \frac{1}{b})$
2. B. $\frac{ρ}{4 π} (\frac{1}{a} + \frac{1}{b})$
3. C. $\frac{ρ}{2 π} (\frac{1}{a} - \frac{1}{b})$
4. D. $\frac{ρ}{4 π} (\frac{1}{a} - \frac{1}{b})$
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Answer: D
Q342019 · 9 Apr 2019 · Shift 1
A wire of resistance R is bent to form a square ABCD as shown in the figure. The effective resistance between E and C is : (E is mid-point of arm CD)
1. A. $\frac{7}{64} R$
2. B. $\frac{1}{16} R$
3. C.R
4. D. $\frac{3}{4} R$
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Answer: A
Q432019 · 9 Apr 2019 · Shift 1
A moving coil galvanometer has resistance $50 Ω$ and it indicates full deflection at 4mA current. A voltmeter is made using this galvanometer and a $5 kΩ$ resistance. The maximum voltage, that can be measured using this voltmeter, will be close to :
1. A.15 V
2. B.10 V
3. C.40 V
4. D.20 V
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Answer: D
Q322019 · 9 Apr 2019 · Shift 2
A metal wire of resistance $3 Ω$ is elongated to make a uniform wire of double its previous length. This new wire is now bent and the ends joined to make a circle. If two points on this circle make an angle $6 0^{\circ}$ at the centre, the equivalent resistance between these two points will be :-
1. A. $5/2 Ω$
2. B. $12/5 Ω$
3. C. $7/2 Ω$
4. D. $5/3 Ω$
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Answer: D
Q332019 · 9 Apr 2019 · Shift 2
The resistance of a galvanometer is 50 ohm and the maximum current which can be passed through it is 0.002 A. What resistance must be connected to it in order to convert it into an ammeter of range 0 – 0.5 A ?
1. A.0.02 ohm
2. B.0.2 ohm
3. C.0.002 ohm
4. D.0.5 ohm
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Answer: B
Q312019 · 8 Apr 2019 · Shift 2
A circuit connected to an ac source of emf $e = e_{0} sin (100 t)$ with t in seconds, gives a phase difference of $π /4$ between the emf e and current i. Which of the following circuits will exhibit this ?
1. A.RC circuit with $R = 1 kΩ$ and $C = 1 μ F$
2. B.RL circuit with $R = 1 kΩ$ and $L = 1 mH$
3. C.RC circuit with $R = 1 kΩ$ and $C = 10 μ F$
4. D.RL circuit with $R = 1 kΩ$ and $L = 10 mH$
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Answer: C
Q342019 · 8 Apr 2019 · Shift 2
A cell of internal resistance r drives current through an external resistance R. The power delivered by the cell to the external resistance will be maximum when :-
1. A.R = 1000 r
2. B.R = r
3. C.R = 2r
4. D.R = 0.001 r
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Answer: B
Q512019 · 8 Apr 2019 · Shift 2
1. A.13/24
2. B.7/18
3. C.9/32
4. D.20/3
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Answer: C
Q572019 · 8 Apr 2019 · Shift 2
1. A.0.25 V
2. B.0.20 V
3. C.0.50 V
4. D.0.75 V
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Answer: A
Q412019 · 12 Jan 2019 · Shift 1
1. A. $5 Ω$
2. B. $25 Ω$
3. C. $12 Ω$
4. D. $22 Ω$
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Answer: D