JEE Questions for Physics Current Electricity I Quiz 20 - MCQExams.com

In a meter bridge, the balancing length from the left end (standard resistance of one ohm is in the right gap) is found to be 20 cm. The value of the unknownresistance is
  • 0.8 Ω
  • 0.5 Ω
  • 0.4 Ω
  • 0.25 Ω
In the circuit shown P ≠ R, the reading of the galvanometer is same with switch S open or closed. Then
Physics-Current Electricity I-66083.png
  • IR = IG
  • IP = IG
  • IQ = IG
  • IQ = IR
In the following Wheatstone bridge P/Q = R/S. If keyK is closed, then the galvanometer will show deflection
Physics-Current Electricity I-66085.png
  • In left side
  • In right side
  • No deflection
  • In either side
A galvanometer having a resistance of 8 ohm is shunted by a wire of resistance 2 ohm. If the total current is 1 amp, the part of it passing through the shunt will be
  • 0.25 amp
  • 0.8 amp
  • 0.2 amp
  • 0.5 amp
A galvanometer whose resistance is 120 Ω gives full scale deflection with a current of 0.05 A so that it can read a maximum current of 10 A. A shunt resistance is added in parallel with it. The resistance of the ammeter so formed is
  • 0.06 Ω
  • 0.006 Ω
  • 0.6 Ω
  • 6 Ω
We have a galvanometer of resistance 25 Ω. It is shunted by a 2.5 Ω wire. The part of total current that flows through the galvanometer is given as

  • Physics-Current Electricity I-66089.png
  • 2)
    Physics-Current Electricity I-66090.png

  • Physics-Current Electricity I-66091.png

  • Physics-Current Electricity I-66092.png
If the resistivity of a potentiometer wire be p and area of cross-section be A, then what will be potential gradient along the wire?

  • Physics-Current Electricity I-66094.png
  • 2)
    Physics-Current Electricity I-66095.png

  • Physics-Current Electricity I-66096.png

  • Physics-Current Electricity I-66097.png
A voltmeter has resistance of 2000 ohm and it can measure upto 2 V. If we want to increase its range to10 V, then the required resistance in series will be
  • 2000 Ω
  • 4000 Ω
  • 6000 Ω
  • 8000 Ω
The arrangement as shown in figure is called as
Physics-Current Electricity I-66100.png
  • Potential divider
  • Potential adder
  • Potential substracter
  • Potential multiplier
A potentiometer wire of length 1 m and resistance 10 Ω is connected in series with a cell of e.m.f. 2V with internal resistance 1 Ω and a resistance box including a resistance R. If potential difference between the ends of the wire is 1 mV, the value of R is
  • 20000 Ω
  • 19989 Ω
  • 10000 Ω
  • 9989 Ω
The ammeter A reads 2 A and the voltmeter V reads 20 V. The value of resistance R is (Assuming finite resistance\'s of ammeter and voltmeter)
Physics-Current Electricity I-66102.png
  • Exactly 10 ohm
  • Less than 10 ohm
  • More than 10 ohm
  • We cannot definitely say
A galvanometer of 25 Ω resistance can read a maximum current of 6mA. It can be used as a voltmeter to measure a maximum of 6 V by connecting a resistance to the galvanometer. Identify the correct choice in thegiven answers
  • 1025 Ω in series
  • 1025 Ω in parallel
  • 975 Ω in series
  • 975 Ω in parallel
A galvanometer has 30 divisions and a sensitivity 16 μA/div. It can be converted into a voltmeter to read 3 V by connecting
  • Resistance nearly 6 k Ω in series
  • 6 k Ω. in parallel
  • 500 Ω in series
  • It cannot be converted
A potentiometer having the potential gradient of 2 mV/cm is used to measure the difference of potential across a resistance of 10 ohm. If a length of 50 cm of the potentiometer wire is required to get the null point, the current passing through the 10 ohm resistor is (in mA)
  • 1
  • 2
  • 5
  • 10
In a circuit 5 percent of total current passes through a galvanometer. If resistance of the galvanometer is G then value of the shunt is
  • 19 G
  • 20 G

  • Physics-Current Electricity I-66107.png

  • Physics-Current Electricity I-66108.png
The measurement of voltmeter in the following circuitis
Physics-Current Electricity I-66111.png
  • 2.4 V
  • 3.4 V
  • 4.0 V
  • 6.0 V
If an ammeter is to be used in place of a voltmeter then we must connect with the ammeter a
  • Low resistance in parallel
  • High resistance in parallel
  • High resistance in series
  • Low resistance in series
A 10 m long wire of 20 Ω resistance is connected with a battery of 3 volt e.m.f. (negligible internal resistance) and a 10 Ω resistance is joined to it is series. Potential gradient along wire in volt per meter is
  • 0.02
  • 0.3
  • 0.2
  • 1.3
A potentiometer has uniform potential gradient across it. Two cells connected in series (i) to support each other and (ii) to oppose each other are balanced over 6 m and 2 m respectively on the potentiometer wire. The e.m.f.\'s of the cells are in the ratio of
  • 1 : 2
  • 1 : 1
  • 3 : 1
  • 2 : 1
The material of wire of potentiometer is
  • Copper
  • Steel
  • Manganin
  • Aluminum
To convert a 800 mV range milli voltmeter of resistance 40 Ω into a galvanometer of 100 mA range, the resistance to be connected as shunt is
  • 10 Ω
  • 20 Ω
  • 30 Ω
  • 40 Ω
The potential difference across the 100 Ω resistance in the following circuit is measured by a voltmeter of 900 Ω resistance. The percentage error made in readingthe potential difference is
Physics-Current Electricity I-66115.png

  • Physics-Current Electricity I-66116.png
  • 0.1
  • 1.0
  • 10.0
A galvanometer, having a resistance of 50 Ω gives a full scale deflection for a current of 0.05 A. The length in meter of a resistance wire of area of cross-section 2.97 × 10–2cm2 that can be used to convert the galvanometer into an ammeter which can read a maximum of 5 A current is (Specific resistance of the wire = 5 × 10–7 m Ω)
  • 9
  • 6
  • 3
  • 1.5
Resistance of 100 cm long potentiometer wire is 10 Ω, it is connected to a battery (2 volt) and a resistance R in series. A source of 10 mV gives null point at 40 cmlength, then external resistance R is
  • 490 Ω
  • 790 Ω
  • 590 Ω
  • 990 Ω
The current flowing in a coil of resistance 90 Ω is to be reduced by 90%. What value of resistance should beconnected in parallel with it
  • 9 Ω
  • 90 Ω
  • 1000 Ω
  • 10 Ω
A galvanometer of 50 ohm resistance has 25 divisions. A current of 4 × 10–4 ampere gives a deflection of onedivision. To convert this galvanometer into a voltmeter having a range of 25 volts, it should be connected witha resistance of
  • 2500 Ω as a shunt
  • 2450 Ω as a shunt
  • 2550 Ω in series
  • 2450 Ω in series
A galvanometer of resistance, G, is shunted by a resistance S ohm. To keep the main current in the circuit unchanged, the resistance to be put in serieswith the galvanometer is

  • Physics-Current Electricity I-66122.png
  • 2)
    Physics-Current Electricity I-66123.png

  • Physics-Current Electricity I-66124.png

  • Physics-Current Electricity I-66125.png
A milli voltmeter of 25 milli volt range is to be converted into an ammeter of 25 ampere range. The value (in ohm) of necessary shunt will be
  • 0.001
  • 0.01
  • 1
  • 0.05
In the circuit shown the cells A and B have negligible resistances. For VA = 12 V, R1 = 500 Ω and R = 100 Ω the galvanometer (G) shows no deflection. The value of VB is
Physics-Current Electricity I-66128.png
  • 4 V
  • 2 V
  • 12 V
  • 6 V
In an electrical cable there is a single wire of radius 9 mm of copper. Its resistance is 5 Ω. The cable is replaced by 6 different insulated copper wires, the radius of each wire is 3 mm. Now the total resistance ofthe cable will be
  • 7.5 Ω
  • 45 Ω
  • 90 Ω
  • 270 Ω
In the figure shown, the capacity of the condense C is 2μF. The current in 2 Ω resistor is
Physics-Current Electricity I-66131.png
  • 9 A
  • 0.9 A

  • Physics-Current Electricity I-66132.png

  • Physics-Current Electricity I-66133.png
When the key K is pressed at time t = 0, which of the following statements about the current I in the resistor AB of the given circuit is true?
Physics-Current Electricity I-66135.png
  • I = 2 mA at all t
  • I = mA oscillates between 1 mA and 2 mA
  • I =1mA all t
  • At t = 0, / = 2 mA and with time it goes to 1 mA
A torch bulb rated as 4.5 W, 1.5 V is connected as shown in the figure. The e.m.f. of the cell needed to make the bulb glow at full intensity is
Physics-Current Electricity I-66137.png
  • 4.5 V
  • 1.5 V
  • 2.67 V
  • 13.5 V
In the circuit shown, the value of each resistance is r, then equivalent resistance of circuit between points A and B will be
Physics-Current Electricity I-66139.png
  • (4/r
  • 3r/2
  • r/3
  • 8r/7
Two cells of equal e.m.f. and of internal resistances r1 and r2(r1> r2)are connected in series. On connecting this combination to an external resistance R, it is observed that the potential difference across the first cell becomes zero. The value of R will be

  • Physics-Current Electricity I-66141.png
  • 2)
    Physics-Current Electricity I-66142.png

  • Physics-Current Electricity I-66143.png

  • Physics-Current Electricity I-66144.png
In the circuit shown below E1 = 4.0 V, R1 = 2 Ω, E2 = 6.0 V, R2 = 4 Ω and R3 = 2 Ω. The current I1 is
Physics-Current Electricity I-66147.png
  • 1.6 A
  • 1.8 A
  • 1.25 A
  • 1.0 A
An ionization chamber with parallel conducting plates as anode and cathode has 5 × 107 electrons and the same number of singly-charged positive ions per cm3.
The electrons are moving at 0.4 m/s. The current density from anode to cathode is 4 μA/m2. The velocity of positive ions moving towards cathode is
  • 0.4 m/s
  • 16 m/s
  • Zero
  • 0.1 m/s
What is the equivalent resistance between the points A and B of the network?
Physics-Current Electricity I-66150.png

  • Physics-Current Electricity I-66151.png
  • 2)
    Physics-Current Electricity I-66152.png

  • Physics-Current Electricity I-66153.png

  • Physics-Current Electricity I-66154.png
In the circuit element given here, if the potential at point B, VB = 0, then the potentials of A and D are givenas
Physics-Current Electricity I-66156.png
  • VA = 1.5V, VD = + 2V
  • VA = + 1.5V, VD = + 2V
  • VA = + 1.5V, VD = + 0.4V
  • VA = + 1.5V, VD = – 0.5V
The equivalent resistance between the points P and Q in the network given here is equal to (given r = 3/2 Ω)
Physics-Current Electricity I-66158.png

  • Physics-Current Electricity I-66159.png
  • 2)
    Physics-Current Electricity I-66160.png

  • Physics-Current Electricity I-66161.png

  • Physics-Current Electricity I-66162.png
Find the equivalent resistance across the terminals of source of e.m.f. 24 V for the circuit shown in figure
Physics-Current Electricity I-66226.png
  • 15Ω
  • 10Ω
  • 5Ω
  • 4Ω
The resistance of a wire of iron is 10 ohm and temp. Coefficient of resistance is 5 × 10–3/° C. At 20°C itcarries 30 milliampere of current. Keeping constant potential difference between its ends, the temperature of the wire is raised to 120°C . The current in milliampere that flows in the wire is
  • 20
  • 15
  • 10
  • 40
In the circuit shown here, the readings of the ammeterand voltmeter are
Physics-Current Electricity I-66165.png
  • 6 A, 60 V
  • 0.6 A, 6 V
  • 6/11 A, 60/11 V
  • 11/6 A, 11/60 V
Length of a hollow tube is 5m, its outer diameter is 10 cm and thickness of its wall is 5 mm. If resistivity of the material of the tube is 1.7 × 10–8Ω× m thenresistance of tube will be
  • 5.6 × 10–5Ω
  • 2 × 10–5Ω
  • 4 × 10–5Ω
  • None of these
As the switch S is closed in the circuit shown in figure, current passing through it is
Physics-Current Electricity I-66168.png
  • 4.5 A
  • 6.0 A
  • 3.0 A
  • Zero

Physics-Current Electricity I-66170.png
  • 9.9 Ω
  • 11 Ω
  • 8.8 Ω
  • 7.7 Ω
The reading of the ideal voltmeter in the adjoining diagram will be
Physics-Current Electricity I-66172.png
  • 4 V
  • 8 V
  • 12 V
  • 14 V
If voltage across a bulb rated 220 Volt – 100 Watt drops by 2.5% of its rated value, the percentage of the rated value by which the power would decrease is
  • 20 %
  • 2.5 %
  • 5 %
  • 10 %
A ring is made of a wire having a resistance R0 = 12 Ω. Find the points A and B as shown in the figure, at which a current carrying conductor should be connected so that the resistance R of the sub circuit between thesepoints is equal to 8/3 Ω
Physics-Current Electricity I-66175.png

  • Physics-Current Electricity I-66176.png
  • 2)
    Physics-Current Electricity I-66177.png

  • Physics-Current Electricity I-66178.png

  • Physics-Current Electricity I-66179.png
Which of the adjoining graphs represents ohmic resistance?

  • Physics-Current Electricity I-66181.png
  • 2)
    Physics-Current Electricity I-66182.png

  • Physics-Current Electricity I-66183.png

  • Physics-Current Electricity I-66184.png
0:0:1


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