Objective type questions on Electric Current, Ohm’s Law, Resistance, Kirchhoff’s Law, Measuring Instruments and current electricity with answers.
Electric Current Physics Quiz:
Ques. What constitutes current in a metal wire?
(a) Electrons
(b) Protons
(c) Neutrons
(d) None of these
Ques. If a 0.1 % increase in length due to stretching, the percentage increase in its resistance will be
(a) 0.2 %
(b) 2 %
(c) 1 %
(d) 0.1 %
Ques. When electric current passes through a wire it behaves like a
(a) Fuse
(b) Battery
(c) Magnet
(d) Element
Ques. If resistance of voltmeter is 10000 ohm and resistance of ammeter is 2 ohm then find R when voltmeter reads 12V and ammeter reads 0.1 A
(a) 118 ohm
(b) 120 ohm
(c) 124 ohm
(d) 114 ohm
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Ques. A piece of wire of resistance 4 ohms is bent through 180o at its mid point and the two halves are twisted together, then the resistance is
(a) 8 ohms
(b) 1 ohm
(c) 2 ohms
(d) 5 ohms
Ques. A potentiometer consists of a wire of length 4 m and resistance 10 ohm. It is connected to a cell of e.m.f. 2 V. The potential difference per unit length of the wire will be
(a) 0.5 V/m
(b) 2 V/m
(c) 5 V/m
(d) 10 V/m
Ques. Resistance in the two gaps of a meter bridge are 10 ohm and 30 ohm respectively. If the resistances are interchanged the balance point shifts by
(a) 33.3 cm
(b) 66.67cm
(c) 25 cm
(d) 50 cm
Ques. It is easier to start a car engine on a hot day than on a cold day. This is because the internal resistance of the car battery
(a) Decreases with rise in temperature
(b) Increases with rise in temperature
(c) Decreases with a fall in temperature
(d) Does not change with a change in temperature
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Ques. The equivalent resistance of resistors connected in series is always
(a) Equal to the mean of component resistors
(b) Less than the lowest of component resistors
(c) In between the lowest and the highest of component resistors
(d) Equal to sum of component resistors
Ques. An ammeter whose resistance is 180 ohm gives full scale deflection when current is 2 mA. The shunt required to convert it into an ammeter reading 20 mA (in ohms) is
(a) 18
(b) 20
(c) 0.1
(d) 10
Ques. 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)
(a) 1
(b) 2
(c) 5
(d) 10
Ques. The reciprocal of resistance is
(a) Conductance
(b) Resistivity
(c) Voltage
(d) None of these
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Ques. The internal resistance of a cell depends on
(a) The distance between the plates
(b) The area of the plates immersed
(c) The concentration of the electrolyte
(d) All the these
Ques. The tangent galvanometer, when connected in series with a standard resistance can be used as
(a) An ammeter
(b) A voltmeter
(c) A wattmeter
(d) Both an ammeter and a voltmeter
Ques. Which is a wrong statement?
(a) The Wheatstone bridge is most sensitive when all the four resistances are of the same order
(b) In a balanced Wheatstone bridge, interchanging the positions of galvanometer and cell affects the balance of the bridge
(c) Kirchhoff’s first law (for currents meeting at a junction in an electric circuit) expresses the conservation of charge
(d) The rheostat can be used as a potential divider
Ques. The resistivity of a wire depends on its
(a) Length
(b) Area of cross-section
(c) Shape
(d) Material
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Ques. Potential gradient is defined as
(a) Fall of potential per unit length of the wire
(b) Fall of potential per unit area of the wire
(c) Fall of potential between two ends of the wire
(d) Potential at any one end of the wire
Ques. The current in a simple series circuit is 5.0 amp. When an additional resistance of 2.0 ohms is inserted, the current drops to 4.0 amp. The original resistance of the circuit in ohms was
(a) 1.25
(b) 8
(c) 10
(d) 20
Ques. A galvanometer can be converted into an ammeter by connecting
(a) Low resistance in series
(b) High resistance in parallel
(c) Low resistance in parallel
(d) High resistance in series
Ques. A uniform wire of resistance 9 ohm is cut into 3 equal parts. They are connected in the form of equilateral triangle ABC. A cell of e.m.f. 2 V and negligible internal resistance is connected across B and C. Potential difference across AB is
(a) 1 V
(b) 2 V
(c) 3 V
(d) 0.5 V
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Ques. The material of wire of potentiometer is
(a) Copper
(b) Steel
(c) Manganin
(d) Aluminium
Ques. A copper wire of resistance R is cut into ten parts of equal length. Two pieces each are joined in series and then five such combinations are joined in parallel. The new combination will have a resistance
(a) R
(b) R/4
(c) R/5
(d) R/25
Ques. An energy source will supply a constant current into the load if its internal resistance is
(a) Zero
(b) Non-zero but less than the resistance of the load
(c) Equal to the resistance of the load
(d) Very large as compared to the load resistance
Ques. A wire of resistance R is divided in 10 equal parts. These parts are connected in parallel, the equivalent resistance of such connection will be
(a) 0.01 R
(b) 0.1 R
(c) 10 R
(d) 100 R
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Ques. Current provided by a battery is maximum when
(a) Internal resistance equal to external resistance
(b) Internal resistance is greater than external resistance
(c) Internal resistance is less than external resistance
(d) None of these
Ques. The length of the wire is doubled. Its conductance will be
(a) Unchanged
(b) Halved
(c) Quadrupled
(d) 1/4 of the original value
Ques. For driving a current of 2 A for 6 minutes in a circuit, 1000 J of work is to be done. The e.m.f. of the source in the circuit is
(a) 1.38 V
(b) 1.68 V
(c) 2.04 V
(d) 3.10 V
Ques. By increasing the temperature, the specific resistance of a conductor and a semiconductor
(a) Increases for both
(b) Decreases for both
(c) Increases, decreases
(d) Decreases, increases
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Ques. A torch battery consisting of two cells of 1.45 volts and an internal resistance 0.15 ohm, each cell sending currents through the filament of the lamps having resistance 1.5ohms. The value of current will be
(a) 16.11 amp
(b) 1.611 amp
(c) 0.1611 amp
(d) 2.6 amp
Ques. The resistance of a conductor is 5 ohm at 50oC and 6 ohm at 100oC. Its resistance at 0oC is
(a) 1 ohm
(b) 2 ohm
(c) 3 ohm
(d) 4 ohm
Ques. By a cell a current of 0.9 A flows through 2 ohm resistor and 0.3 A through 7 ohm resistor. The internal resistance of the cell is
(a) 0.5 ohm
(b) 1.0 ohm
(c) 1.2 ohm
(d) 2.0 ohm
