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2019 39 questions

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
Q452019 · 12 Jan 2019 · Shift 1
1. A. $6 A$
2. B. $7.5 A$
3. C. $3 A$
4. D. $5.5 A$
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Answer: A
Q512019 · 12 Jan 2019 · Shift 1
1. A. $\overset{ˉ}{A} B$
2. B. $A B + \overline{A B}$
3. C. $A \overset{ˉ}{B} + \overset{ˉ}{A} B$
4. D. $A \overset{ˉ}{B}$
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Answer: D
Q532019 · 12 Jan 2019 · Shift 1
1. A. $0.3 m$
2. B. $0.25 m$
3. C. $0.35 m$
4. D. $0.2 m$
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Answer: B
Q592019 · 12 Jan 2019 · Shift 1
An ideal battery of $4 V$ and resistance R are connected in series in the primary circuit of a potentiometer of length $1 m$ and resistance $5 Ω$ . The value of R, to give a potential difference of $5 mV$ across $10 cm$ of potentiometer wire, is :
1. A. $480 Ω$
2. B. $495 Ω$
3. C. $490 Ω$
4. D. $395 Ω$
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Answer: D
Q332019 · 12 Jan 2019 · Shift 2
A galvanometer, whose resistance is 50 ohm, has 25 divisions in it. When a current of $4 \times 1 0^{- 4} A$ passes through it, its needle ( pointer) deflects by one division. To use this galvanometer as a voltmeter of range 2.5 V, it should be connected to a resistance of :
1. A. $200 ohm$
2. B. $250 ohm$
3. C. $6200 ohm$
4. D. $6250 ohm$
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Answer: A
Q402019 · 12 Jan 2019 · Shift 2
1. A. $1.1 A, - 0.4 A, 0.4 A$
2. B. $- 0.4 A, 0.4 A, 1.1 A$
3. C. $0.4 A, 1.1 A, 0.4 A$
4. D. $1.1 A, 0.4 A, 0.4 A$
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Answer: D
Q462019 · 11 Jan 2019 · Shift 2
A galvanometer having a resistance of $20 Ω$ and 30 divisions on both sides has figure of merit $0.005 ampere/division$ . The resistance that should be connected in series such that it can be used as a voltmeter upto 15 volt, is:
1. A. $120 Ω$
2. B. $125 Ω$
3. C. $80 Ω$
4. D. $100 Ω$
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Answer: C
Q552019 · 11 Jan 2019 · Shift 2
1. A. $6 V$
2. B. $3 V$
3. C. $2 V$
4. D. $1 V$
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Answer: C
Q562019 · 11 Jan 2019 · Shift 2
1. A.0.027
2. B.0.030
3. C.0.036
4. D.0.020
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Answer: D