JEE Questions for Physics Current Electricity I Quiz 12 - MCQExams.com

A potentiometer wire of length L and resistance 10 Ω is connected in series with a battery of e.m.f. 2.5 V and a resistance in its primary circuit. The null point corresponding to a cell of e.m.f. 1 V is obtained at a distance L/2. If the resistance in the primary circuit is doubled then the position of new null point will be
  • 0.4 L
  • 0.5 L
  • 0.6 L
  • 0.8 L
An ammeter with internal resistance 90 Ω reads 1.85 A when connected in a circuit containing a battery and two resistors 700 Ω and 410 Ω in series. Actual current will be
  • 1.85 A
  • Greater than 1.85 A
  • Less than 1.85 A
  • None of these
The circuit shown here is used to compare the e.m.f.\'s of two cells E1 and E2 (E1> E2). The null point is at C when the galvanometer is connected to E1. When the galvanometer is connected to E2, the null point will be
Physics-Current Electricity I-65314.png
  • To the left of C
  • To the right of C
  • At C itself
  • No where on AB
In an experiment to measure the internal resistance of a cell by potentiometer, it is found that the balance point is at a length of 2m when the cell is shunted by a 5 Ω resistance; and is at a length of 3m when the cell is shunted by a 10 Ω resistance. The internal resistance of the cell is, then
  • 1.5 Ω
  • 10 Ω
  • 15 Ω
  • 1 Ω
A potentiometer circuit shown in the figure is set up to measure e.m.f. of a cell E. As the point P moves from X to V the galvanometer G shows deflection always in one direction, but the deflection decreases continuously until Y is reached. In order to obtain balance point between X and Y it is necessary to
Physics-Current Electricity I-65317.png
  • Decrease the resistance R
  • Increase the resistance R
  • Reverse the terminals of battery V
  • Reverse the terminals of cell E
In the Wheatstone\'s bridge (shown in figure) X = Y and A >B. The direction of the current between ab will be
Physics-Current Electricity I-65318.png
  • From a to b
  • From b to a
  • From b to a through c
  • From a to b through c

Physics-Current Electricity I-65320.png
  • The galvanometer shows a deflection when switch S is closed
  • The galvanometer shows a deflection when switch S is open
  • The galvanometer shows no change in deflection whether S is open or closed
  • The galvanometer shows no deflection
In the Wheatstone bridge shown below, in order to balance the bridge, we must have
Physics-Current Electricity I-65321.png
  • R1 = 3 Ω ; R2 = 3 Ω
  • R1 = 6 Ω ; R2 =15 Ω
  • R1 = 1.5 Ω ; R2 = any finite value
  • R1 = 3 Ω ; R2 = any finite value
A resistance of 4 Ω and a wire of length 5 metres and resistance 5 Ω are joined in series and connected to a cell of e.m.f. 10 V and internal resistance 1 Ω. A parallel combination of two identical cells is balanced across 300 cm of the wire. The e.m.f. E of each cell is
Physics-Current Electricity I-65323.png
  • 1.5 V
  • 3.0 V
  • 0.67 V
  • 1.33 V
The resistivity of a potentiometer wire is 40 × 10–8 ohm m and its area of cross-section is 8 × 10–6m2. If 0.2 amp current is flowing through the wire, the potential gradient will be
  • 10–2 volt/m
  • 10–1 volt/m
  • 3.2 × 10–2 volt/m
  • 1 volt/m
Potentiometer wire of length 1 m is connected in series with 490 Ω resistance and 2 V battery. If 0.2 mV /cm is the potential gradient, then resistance of the potentiometer wire is
  • 4.9 Ω
  • 7.9 Ω
  • 5.9 Ω
  • 6.9 Ω
The resistance of an ideal voltmeter is
  • Zero
  • Very low
  • Very large
  • Infinite
A 100 V voltmeter of internal resistance 20 kΩ in series with a high resistance R is connected to a 110 V line. The voltmeter reads 5 V, the value of R is
  • 210 KΩ
  • 315 KΩ
  • 420 KΩ
  • 440 KΩ
Constantan wire is used in making standard resistances because its
  • Specific resistance is low
  • Density is high
  • Temperature coefficient of resistance is negligible
  • Melting point is high
The net resistance of a voltmeter should be large to ensure that
  • It does not get overheated
  • It does not draw excessive current
  • It can measure large potential difference
  • It does not appreciably change the potential difference to be measured
A 36 Ω galvanometer is shunted by resistance of 4 Ω. The percentage of the total current, which passes through the galvanometer is
  • 8 %
  • 9 %
  • 10 %
  • 91 %
In the circuit as shown in figure the
Physics-Current Electricity I-65616.png
  • Resistance R = 46 Ω
  • Current through 20 Ω resistance is 0.1 A
  • Potential difference across the middle resistance is 2V
  • All option are correct
In the circuit shown P ≠ R, the reading of the galvanometer is same with switch S open or closed. Then
Physics-Current Electricity I-65328.png
  • IR = IG
  • IP = IG
  • IQ = IG
  • IQ = IR
In the following Wheatstone bridge P/Q = R/S . If key K is closed, then the galvanometer will show deflection
Physics-Current Electricity I-65329.png
  • In left side
  • In right side
  • No deflection
  • In either side
If resistance of voltmeter is 10000 Ω and resistance of ammeter is 2 Ω, then find R when voltmeter reads 12V and ammeter reads 0.1 A
  • 118 Ω
  • 120 Ω
  • 124 Ω
  • 114 Ω
Two resistances are connected in two gaps of a metre bridge. The balance point is 20 cm from the zero end. A resistance of 15 ohms is connected in series with the smaller of the two. The null point shifts to 40 cm. The value of the smaller resistance in ohms is
  • 3
  • 6
  • 9
  • 12
In a potentiometer experiment, the galvanometer shows no deflection when a cell is connected across 60 cm of the potentiometer wire. If the cell is shunted by a resistance of 6 Ω, the balance is obtained across 50 cm of the wire. The internal resistance of the cell is
  • 0.5 Ω
  • 0.6 Ω
  • 1.2 Ω
  • 1.5 Ω
A voltmeter of resistance 1000 Ω gives full scale deflection when a current of 100 mA flows through it. The shunt resistance required across it to enable it to be used as an ammeter reading 1 A at full scale deflection is
  • 10000 Ω
  • 9000 Ω
  • 222 Ω
  • 111 Ω
A moving coil galvanometer of resistance 100 Ω is used as an ammeter using a resistance 0.1 Ω. The maximum deflection current in the galvanometer is 100 μA. Find the minimum current in the circuit so that the ammeter shows maximum deflection
  • 100.1 mA
  • 1000.1 mA
  • 10.01 mA
  • 1.01 m
In the adjoining circuit, the e.m.f. of the cell is 2 volt and the internal resistance is negligible. The resistance of the voltmeter is 80 ohm. The reading of the voltmeter will be
Physics-Current Electricity I-65335.png
  • 0.80 volt
  • 1.60 volt
  • 1.33 volt
  • 2.00 volt
If the resistivity of a potentiometer wire be ρ and area of cross-section be A, then what will be potential gradient along the wire

  • Physics-Current Electricity I-65337.png
  • 2)
    Physics-Current Electricity I-65338.png

  • Physics-Current Electricity I-65339.png

  • Physics-Current Electricity I-65340.png
A voltmeter has resistance of 2000 ohm and it can measure upto 2 V. If we want to increase its range to 10 V, then the required resistance in series will be
  • 2000 Ω
  • 4000 Ω
  • 6000 Ω
  • 8000 Ω
With a potentiometer null point were obtained at 140 cm and 180 cm with cells of e.m.f 1.1 V and one unknown X volt. Unknown e.m.f. is
  • 1.1 V
  • 1.8 V
  • 2.4 V
  • 1.41V
The arrangement as shown in figure is called as
Physics-Current Electricity I-65344.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 2 V 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
In a balanced Wheatstone\'s network, the resistances in the arms Q and S are interchanged. As a result of this
  • Network is not balanced
  • Network is still balanced
  • Galvanometer shows zero deflection
  • Galvanometer and the cell must be interchanged to balance
The resistance of a galvanometer coil is R. What is the shunt resistance required to convert it into an ammeter of range 4 times?

  • Physics-Current Electricity I-65346.png
  • 2)
    Physics-Current Electricity I-65347.png

  • Physics-Current Electricity I-65348.png
  • 4R
If an ammeter is connected in parallel to a circuit, it is likely to be damaged due to excess
  • Current
  • Voltage
  • Resistance
  • All of these
In the given figure, battery E is balanced on 55 cm length of potentiometer wire but when a resistance of 10 Ω is connected in parallel with the battery then it balances on 50 cm length of the potentiometer wire then internal resistance r of the battery is
Physics-Current Electricity I-65350.png
  • 1 Ω
  • 3 Ω
  • 10 Ω
  • 5 Ω
In a potentiometer experiment the balancing with a cell is at length 240 cm. On shunting the cell with a resistance of 2 Ω, the balancing length becomes 120 cm. The internal resistance of the cell is
  • 4 Ω
  • 2 Ω
  • 1 Ω
  • 0.5 Ω
The resistance of an ideal ammeter is
  • Infinite
  • Very high
  • Small
  • Zero
A galvanometer has a resistance of 25 ohm and a maximum of 0.01 A current can be passed through it. In order to change it into an ammeter of range 10 A, the shunt resistance required is
  • 5/999 ohm
  • 10/999 ohm
  • 20/999 ohm
  • 25/999 ohm
In the circuit shown, a meter bridge is in its balanced state. The meter bridge wire has a resistance 0.1 ohm/cm. The value of unknown resistance X and the current drawn from the battery of negligible resistance
Physics-Current Electricity I-65354.png
  • 6Ω, 5 amp
  • 10Ω, 0.1 amp
  • 4Ω, 1.0 amp
  • 12Ω, 0.5 amp
Voltmeters V1 and V2are connected in series across a D.C. line. V1 reads 80 volt and has a per volt resistance of 200 ohm. V2 has a total resistance of 32 kilo ohm. The line voltage is
  • 120 volt
  • 160 volt
  • 220 volt
  • 240 volt
AB is a potentiometer wire of length 100 cm and its resistance is 10 ohm. It is connected in series with a resistance R = 40 ohm and a battery of e.m.f. 2 V and negligible internal resistance. If a source of unknown e.m.f. E is balanced by 40 cm length of the potentiometer wire, the value of E is
Physics-Current Electricity I-65357.png
  • 0.8 V
  • 1.6 V
  • 0.08 V
  • 0.16 V
An ammeter gives full deflection when a current of 2 amp. flows through it. The resistance of ammeter is 12 ohm. If the same ammeter is to be used for measuring a maximum current of 5 amp., then the ammeter must be connected with a resistance of
  • 8 ohm in series
  • 18 ohm in series
  • 8 ohm in parallel
  • 18 ohm in parallel
A voltmeter having resistance of 50 × 103 ohm is used to measure the voltage in a circuit. To increase the range of measurement 3 times the additional series resistance required is
  • 105 ohm
  • 150 k ohm
  • 900 k ohm
  • 9 × 106 ohm
In a potentiometer experiment two cells of e.m.f.\'s E1 and E2are used in series and in conjunction and the balancing length is found to be 58 cm of the wire. If the polarity of E2is reversed, then the balancing length becomes 29 cm. The ratio E1/E2 of the e.m.f. of the two cells is
  • 1 : 1
  • 2 : 1
  • 3 : 1
  • 4 : 1
An ammeter and a voltmeter of resistance R are connected in series to an electric cell of negligible internal resistance. Their readings are A and V respectively. If another resistance R is connected in parallel with the voltmeter
  • Both A and V will increase
  • Both A and V will decrease
  • A will decrease and V will increase
  • A will increase and V will decrease
A wire of length 100 cm is connected to a cell of e.m.f 2 V and negligible internal resistance. The resistance of the wire is 3 Ω. The additional resistance required to produce a potential drop of 1 milli volt per cm is
  • 60 Ω
  • 47 Ω
  • 57 Ω
  • 35 Ω
A galvanometer of resistance 20 Ω is to be converted into an ammeter of range 1 A. If a current of 1 mA produces full scale deflection, the shunt required for the purpose is
  • 0.01 Ω
  • 0.05 Ω
  • 0.02 Ω
  • 0.04 Ω
There are three voltmeters of the same range but of resistances 10000 Ω, 8000 Ω and 4000 Ω respectively. The best voltmeter among these is the one whose resistance is
  • 10000 Ω
  • 8000 Ω
  • 4000 Ω
  • All are equally good
A voltmeter essentially consists of
  • A high resistance, in series with a galvanometer
  • A low resistance, in series with a galvanometer
  • A high resistance in parallel with a galvanometer
  • A low resistance in parallel with a galvanometer
A 100 ohm galvanometer gives full scale deflection at 10 mA. How much shunt is required to read 100 mA?
  • 11.11 ohm
  • 9.9 ohm
  • 1.1 ohm
  • 4.4 ohm
A cell of internal resistance 3 ohm and e.m.f 10 volt is connected to a uniform wire of length 500 cm and resistance 3 ohm. The potential gradient in the wire is
  • 30 mV/cm
  • 10 mV/cm
  • 20 mV/cm
  • 4 mV/cm
0:0:1


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