JEE Questions for Physics Current Electricity I Quiz 15 - MCQExams.com

Two batteries of different e.m.f and different internal resistances are connected as shown. The voltage across AB in volts is
Physics-Current Electricity I-65594.png
  • 5
  • 4
  • 3
  • 2
Assertion A person touching a high power line gets stuck with the line.
Reason The current carrying wires attract the man towards it.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion In a simple battery circuit the point of lowest potential is positive terminal of the battery.
Reason The current flows towards the point of the higher potential as it flows in such a circuit from the negative to the positive terminal.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
In the circuit shown, the reading of ammeter when switch S is open and when switch S is closed respectively are
Physics-Current Electricity I-65614.png
  • 3 A and 4 A
  • 4 A and 4 A
  • 5 A and 6 A
  • 6 A and 7 A
Assertion The temperature coefficient of resistance is positive for metals and negative for p-type semiconductor.
Reason The effective charge carriers in metals are negatively charged whereas in p-type semiconductor they are positively charged.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion In the following circuit e.m.f is 2V and internal resistance of the cell is 1 Ω and R = 1 Ω, then reading of the voltmeter is 1 V.
Reason V = E – ir where E = 2V, i = 2/2 = 1A and 2 R = 1 Ω
Physics-Current Electricity I-65596.png
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion There is no current in the metals in the absence of electric field.
Reason Motion of free electrons is random.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Electric appliances with metallic body have three connections, whereas an electric bulb has a two pin connection.
Reason Three pin connections reduce heating of connecting wires.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The drift velocity of electrons in a metallic wire will decrease, if the temperature of the wire is increased.
Reason On increasing temperature, conductivity of metallic wire decreases.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The electric bulbs glows immediately when switch is on.
Reason The drift velocity of electrons in a metallic wire is very high.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Bending a wire does not effect electrical resistance.
Reason Resistance of wire is proportional to resistivity of material.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion In meter bridge experiment, a high resistance is always connected in series with a galvanometer.
Reason As resistance increases current through the circuit increases.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Voltameter measures current more accurately than ammeter.
Reason Relative error will be small if measured from voltameter.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The e.m.f. of the driver cell in the potentiometer experiment should be greater than the e.m.f. of the cell to be determined.
Reason The fall of potential across the potentiometer wire should not be less than the e.m.f. of the cell to be determined.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The resistance of super-conductor is zero.
Reason The super-conductors are used for the transmission of electric power.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion A potentiometer of longer length is used for accurate measurement.
Reason The potential gradient for a potentiometer of longer length with a given source of e.m.f. becomes small.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Figure shows a simple potentiometer circuit for measuring a small e.m.f. produced by a thermocouple. The meter wire PQ has a resistance 5 Ω and the driver cell has an e.m.f. of 2 V. If a balance point is obtained 0.600 m along PQ when measuring an e.m.f. of 6.00 mV, what is the value of resistance R?
Physics-Current Electricity I-65601.png
  • 995 Ω
  • 1995 Ω
  • 2995 Ω
  • None of the above
If the balance point is obtained at the 35th cm in a metre bridge, the resistances in the left and right gaps are in the ratio of
  • 7 : 13
  • 13 : 7
  • 9 : 11
  • 11 : 9
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-65604.png
  • 15 Ω
  • 10 Ω
  • 5 Ω
  • 4 Ω
In the circuit shown in figure, switch S1 is initially closed and S2is open. Find Va – VVb
Physics-Current Electricity I-65606.png
  • 4 V
  • 8 V
  • 12 V
  • 16 V
The figure here shows a portion of a circuit. What are the magnitude and direction of the current i in the lower right-hand wire?
Physics-Current Electricity I-65608.png
  • 7 A
  • 8 A
  • 6 A
  • 2 A
A battery of 24 cells, each of e.m.f 1.5 V and internal resistance 2 Ω is to be connected in order to send the maximum current through a 12 Ω resistor. The correct arrangement of cells will be
  • 2 rows of 12 cells connected in parallel
  • 3 rows of 8 cells connected in parallel
  • 4 rows of 6 cells connected in parallel
  • All of the above
A voltmeter of resistance 1000 Ω is connected across a resistance of 500 Ω in the given circuit. What will be the reading of voltmeter?
Physics-Current Electricity I-65611.png
  • 1 V
  • 2 V
  • 6 V
  • 4 V
A beam contains 2 × 108 doubly charged positive ions per cubic centimeter, all of which are moving with a speed of 105 m/s. The current density is
  • 6.4 A/m2
  • 3.2 A/m2
  • 1.6 A/m2
  • None of the above
Given figure shows a rectangular block with dimensions x, 2x and 4x. Electrical contacts can be made to the block between opposite pairs of faces (for example, between the faces labelled A–A, B–B and C–C). Between which two faces would the maximum electrical resistance be obtained (A–A : Top and bottom faces, B–B : Left and right faces, C–C : Front and rear faces)
Physics-Current Electricity I-65618.png
  • A – A
  • B – B
  • C – C
  • Same for all three pairs
A battery is connected to a uniform resistance wire AB and B is earthed. Which one of the graphs below shows how the current density J varies along AB?
Physics-Current Electricity I-65620.png

  • Physics-Current Electricity I-65621.png
  • 2)
    Physics-Current Electricity I-65622.png

  • Physics-Current Electricity I-65623.png

  • Physics-Current Electricity I-65624.png
A cylindrical metal wire of length l and cross sectional area S, has resistance R, conductance G, conductivity σ and resistivity ρ. Which one of the following expressions for σ is valid?

  • Physics-Current Electricity I-65625.png
  • 2)
    Physics-Current Electricity I-65626.png

  • Physics-Current Electricity I-65627.png

  • Physics-Current Electricity I-65628.png
A potential divider is used to give outputs of 4 V and 8 V from a 12 V source. Which combination of resistances, (R1 : R2 : R3) gives the correct voltages ?
Physics-Current Electricity I-65630.png
  • 2 : 1 : 2
  • 1 : 1 : 1
  • 2 : 2 : 1
  • 1 : 1 : 2
Find equivalent resistance between A and B
Physics-Current Electricity I-65632.png
  • R
  • 2)
    Physics-Current Electricity I-65633.png

  • Physics-Current Electricity I-65634.png
  • 2R
Following figure shows four situations in which positive and negative charges move horizontally through a region and gives the rate at which each charge moves. Rank the situations according to the effective current through the region greatest first
Physics-Current Electricity I-65636.png
  • i = ii = iii = iv
  • i > ii > iii > iv
  • i = ii = iii > iv
  • i = ii = iii < iv
A and B are two square plates of same metal and same thickness but length of B is twice that of A. Ratio of resistances of A and B is
Physics-Current Electricity I-65638.png
  • 4 : 1
  • 1 : 4
  • 1 : 1
  • 1 : 2
Two conductors are made of the same material and have the same length. Conductor A is a solid wire of diameter 1.0 mm. Conductor B is a hollow tube of outside diameter 2.0 mm and inside diameter 1.0 mm.The resistance ratio RA/RB will be
  • 1
  • 2
  • 3
  • 4
A wire has resistance of 24 Ω is bent in the following shape. The effective resistance between A and B is
Physics-Current Electricity I-65641.png
  • 24 Ω
  • 10 Ω

  • Physics-Current Electricity I-65642.png
  • None of these
In the circuit shown in figure, find the current through the branch BD
Physics-Current Electricity I-65644.png
  • 5 A
  • 0 A
  • 3 A
  • 4 A
Electric field (E) and current density (./) have relation
  • E ∝ J–1
  • E ∝ J

  • Physics-Current Electricity I-65646.png

  • Physics-Current Electricity I-65647.png
Every atom makes one free electron in copper. If 1.1 ampere current is flowing in the wire of copper having 1 mm diameter, then the drift velocity (approx.) will be (Density of copper = 9 × 103 kg m–3 and atomic weight = 63)
  • 0.3 mm/sec
  • 0.1 mm/sec
  • 0.2 mm/sec
  • 0.2 cm/sec
The current flowing through a wire depends on time as I = 3t2 + 2t + 5. The charge flowing through the cross-section of the wire in time from t = 0 to t = 2 sec. is
  • 22 C
  • 20 C
  • 18 C
  • 5 C
The specific resistance of manganin is 50 × 10–8 ohm × m. The resistance of a cube of length 50 cm will be
  • 10–6Ω
  • 2.5 × 10–5Ω
  • 10–8Ω
  • 5 × 10–4Ω
The resistivity of iron is 1 × 10–7 ohm–m. The resistanceof a iron wire of particular length and thickness is 1 ohm. If the length and the diameter of wire both are doubled, then the resistivity in ohm–m will be
  • 1 × 10–7
  • 2 × 10–7
  • 4 × 10–7
  • 8 × 10–7
The temperature coefficient of resistance for a wire is 0.00125/°C. At 300 K its resistance is 1 ohm. The temperature at which the resistance becomes 2 ohm is
  • 1154 K
  • 1100 K
  • 1400 K
  • 1127 K
A wire of a certain material is stretched slowly by ten percent. Its new resistance and specific resistancebecome respectively
  • Both remain the same
  • 1.1 times, 1.1 times
  • 1.2 times, 1.1 times
  • 1.21 times, same
Drift velocity vd varies with the intensity of electric fieldas per the relation

  • Physics-Current Electricity I-65655.png
  • 2)
    Physics-Current Electricity I-65656.png

  • Physics-Current Electricity I-65657.png

  • Physics-Current Electricity I-65658.png
In a conductor 4 coulomb of charge flows for 2 seconds. The value of electric current will be
  • 4 volt
  • 4 ampere
  • 2 ampere
  • 2 volt
In a closed circuit, the current I (in ampere) at an instant of time t (in second) is given by I = 4 – 0.08 t. The number of electrons flowing in 50s through the cross-section of the conductor is
  • 1.25 × 1019
  • 6.25 × 1020
  • 5.25 × 1019
  • 2.55 × 1020
When a piece of aluminum wire of finite length is drawn through a series of dies to reduce its diameter to half its original value, its resistance will become
  • Two times
  • Four times
  • Eight times
  • Sixteen times
A wire 100 cm long and 2.0 mm diameter has a resistance of 0.7 ohm, the electrical resistivity of thematerial is
  • 4.4 × 10–6 ohm × m
  • 2.2 × 10–6 ohm × m
  • 1.1 × 10–6 ohm × m
  • 0.22 × 10–6 ohm × m
In hydrogen atom, the electron makes 6.6 × 1015revolutions per second around the nucleus in an orbit of radius 0.5 × 10–10m . It is equivalent to a current nearly
  • 1 A
  • 1 mA
  • 1μA
  • 1.6 × 10–19A
A wire of length 5 m and radius 1 mm has a resistance of 1 ohm. What length of the wire of the same material at the same temperature and of radius 2 mm will also have a resistance of 1 ohm?
  • 1.25 m
  • 2.5 m
  • 10 m
  • 20 m
Consider a rectangular slab of length L and area of cross-section A. A current I is passed through it. If the length is doubled, the potential drop across the end faces
  • Becomes half of the initial value
  • Becomes one-fourth of the initial value
  • Becomes double the initial value
  • Remains same
Dimensions of a block are 1 cm × 1 cm × 100 cm. If specific resistance of its material is 3 × 10–7ohm–m, then the resistance between the opposite rectangular faces is
  • 3 × 10–9Ω
  • 3 × 10–7Ω
  • 3 × 10–5Ω
  • 3 × 10–3Ω
0:0:1


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