Physics: Electricity - Current Objectives Questions and Answers

50 Solved MCQs on Electricity

Q.The rheostat is used in the circuit to :
A. increase the magnitude of current only 
B. decrease the magnitude of current only
C. increase or decrease the magnitude of current 
D. none of these 

Ans :  (c) increase or decrease the magnitude of current  

1 Electric current originates from which part of an atom?
A. nucleus
B. entire atom acting as a unit
C. positively charged protons
D. negatively charged electrons
Ans: D
Electric current originates from negatively charged electrons

2 Which of the following is true of electrical forces?
A. Like charges attract, unlike charges repel.
B. Electrical forces are produced by electrical charges.
C. Positive and negative charges can combine to produce a third type
D. Electrical forces are weaker than gravitational forces.
Ans: B
Electrical forces are produced by electrical charges

3 How can electric charge be established?
A. Electrons can be removed from atoms and accumulated to produce a negative charge.
B. Atoms from which electrons have been removed produce positive electric charge.
C. Both A and B.
D. Neither A nor B.
Ans: C
Electrons have been removed produce positive electric charge & a negative charge

4 When a person combs her hair, static electricity is sometimes generated by what process?
A. Friction between the comb and hair transfers electrons.
B. Induction between the comb and hair.
C. Deduction between the comb and hair.
D. Contact between the comb and hair results in a charge.
Ans: A
static electricity is sometimes generated by Friction

5 The resistance of the wire varies inversely as:
A. Area of cross section
B. Resistivity
C. Length
D. Temperature
Ans: A
The resistance of the wire varies inversely as Area of cross section

Must Read: 115 Solved MCQs on Electricity

6 Voltage is a form of:
A. Kinetic energy
B. Potential energy
C. both Potential and Kinetic energy
D. None of the above
Ans: B
Voltage is a form of Potential energy

7 The ratio of voltage and electrical current in a closed circuit:
A. Decreases
B. Increases
C. Remains constant
D. Varies
Ans: C
The ratio of voltage and electrical current in a closed circuit Remains constant

8 The curve representing Ohms law is a:
A. Linear
B. cosine function
C. Parabola
D. Hyperbola
Ans: A
The curve representing Ohms law is a Linear

9 Ohm’s law states which relationship between electrical quantities?
A. volts = current times resistance
B. volts = current divided by amps
C. volts = coulombs divided by charge
D. volts = resistance times charge
Ans: A
volts = current times resistance

10 Resistance is a measure of a material’s opposition to
A. voltage
B. current
C. electric force.
D. movement of protons.
Ans: B
Resistance is a measure of a material’s opposition to current

11 Electric current is defined as a flow of
A. electric charge in units of volts per s.
B. protons in units of protons per s.
C. electric charge in units of coulomb per s.
D. electrons in units of electrons per s.
Ans: C
electric charge in units of coulomb per s

12 What are the basic components of a simple electric circuit?
A. energy source
B. connecting wires
C. switch
D. All the above
Ans: D
energy source, wires, and switch are the basic components

13 To produce a electric current what is the requirement?
A. A voltage source
B. A source of energy that moves charges
C. An electric field moving through a conductor
D. Any of the above
Ans: D
to produce a sustained electric current A source of energy, A voltage source An electric field is required

14 Which of the following is not an electrical classification of materials?
A. Semiconductors
B. Semi-insulators
C. Insulators
D. Conductors
Ans: B
Semi-insulators, which sometimes conduct and sometimes insulate

15 Give the name of materials which contain lots of free electrons.
A. insulators
B. conductors
C. semiconductors
D. None of the above
Ans: B
In an atom the free electrons are present at outermost orbit.It can easily flow from one atom to another by applying voltage. So it is called as conductor.

16 Which of the following is not a type of energy source?
A. generator
B. solar cell
C. rheostat
D. battery
Ans: C
“Generator = Mechanical Energy to Electrical Energy,
Solar cell = Light energy to Electrical Energy,
battery = Chemical energy to Electrical Energy.
Rheostat = Variable resistance

17 When two positively charged materials will placed close together then :
A. it will repel each other
B. become negative
C. it will attract each other
D. None of the above
Ans: A
Like charge Repel each other

18 Electrons in the outer orbit are called
A. shells
B. valences
C. nuclei
D. All the above
Ans: B
Electrons in the outer orbit are called valences

19 A series circuit consists of three resistors with values of 140 , 250 , and 220 . The total resistance is
A. 330
B. 610
C. 720
D. None of the above
Ans: B
Series means current is same so all resistors are added
140 + 250 + 220 = 610

20 When will be the current flows in a circuit?
A. a switch is closed
B. a switch is opened
C. switch is either open or closed
D. None of the above
Ans: A
When switch is closed in any circuit it acts as a closed circuit so current flows only in a closed circuit.

Must Read: 115 Solved MCQs on Electricity

21 The unit of electrical charge is the
A. coulomb
B. volt
C. joule
D. watt
Ans: A
1 coulomb is the charge carried carried by 6.25*10^18 electrons

22 When one of three series resistors is removed from a circuit and the circuit is reconnected, the current
A. increases by half
B. increases
C. decreases by half
D. None of the above
Ans: B
When resistance decreases, the current increases. Because R=V/I, resistance and current are inversely proportional.

23 If a 24 V and a 10 V battery are series opposing, the total voltage is
A. 14 V
B. 10 V
C. 24 V
D. 34 V
Ans: A
v1-V2 (i.e): 24-10=14v.

24 A series circuit consists of three resistors. Two resistors are 1.4 k each. The total resistance is 12 k. The value of the third resistor
A. 92 k ohm
B. 920 ohm
C. 9200 ohm
D. None of the above
Ans: C
r1+r2+r3=R
1.4 +1.4 + X=12
x=9.2 Kilo ohm
9200 ohm

25 A 430 resistor, a 210 resistor, and a 100 resistor are all in parallel. The total resistance is :
A. 0.017 ohm
B. 58.82 ohm
C. 58.82 kilo ohm
D. None of the above
Ans: B
1/R = (1/430 + 1/210 + 1/100)
R = 58.82 ohm
26 The SI unit of power is_________.
A. Joule
B. Ampere
C. Watt
D. Ohm
Ans: C
The SI unit of power is Watt

27 According to Ohm’s law, if voltage increases and resistance stays the same:
A. resistance decreases
B. current increases
C. current remains the same
D. current decreases
Ans: B
V=IR
SO if resistance constant, AND if voltage increases Then current also increases because proportional to each other

28 The instrument used for measuring electric current is :
A. galvanometer
B. ammeter
C. voltmeter
D. potentiometer
Ans: B
The instrument used for measuring electric current is ammeter

29 The amount of work done in joules, when one unit electric charge moves from one point to another point in an electric circuit is called :
A. resistance
B. potential difference
C. current
D. charge
Ans: B
The amount of work done in joules, when one unit electric charge moves from one point to another point in an electric circuit is called potential difference

30 The resistance of material depends on :
A. temperature
B. length of conductor
C. area of cross-section
D. All the above
Ans: D

31 The relation between potential difference (V) and current (I) is :
A. V α I
B. V α I2
C. V α 1/I
D. None of the above
Ans: A
V α I , V=IR

32 The relation between potential difference (V) and current (I) was discovered by :
A. Volt
B. Ohm
C. Newton
D. Ampere
Ans: B
The relation between potential difference (V) and current (I) was discovered by Ohm

33 What is the most commonly used conductor in electronics?
A. copper
B. aluminum
C. gold
D. silver
Ans: A

34 Give the name of components which is designed to oppose the flow of current.
A. capacitor
B. resistors
C. inductor
D. EMF
Ans: B

35 What are the different parts of a rheostat?
A. only wiper
B. wiper and resistor track
C. armature
D. oly resistor track
Ans: B

36 The SI unit of electric current is :
A. ohm
B. volt
C. ampere
D. watt
Ans: C
The SI unit of electric current is ampere

37 The rate of flow of an electric charge is known as :
A. electric potential
B. electric resistance
C. electric current
D. None of the above
Ans: C
The rate of flow of an electric charge is known as electric current

38 An ideal voltmeter would have an:
A. Infinite resistance
B. Very low resistance
C. Double the resistance
D. Resistance equal to the circuit
Ans: A
An ideal voltmeter would have an Infinite resistance

39 Resistance ‘R’ of a wire of length “L” is given by the relation:
A. R=L/Ρa
B. R=L/A
C. R=ρL/A
D. None of the above
Ans: C
Resistance ‘R’ of a wire of length “L” is given by the relation R=ρL/A

40 The unit of emf is ___________.
A. volt
B. Joule
C. Ampere
D. Watt
Ans: A
The unit of emf is Volt

41 If a source of EMF is traversed from negative to positive terminal the potential change is:
A. Negative
B. Positive
C. Positive and Negative Both
D. None of the above
Ans: B
If a source of EMF is traversed from negative to positive terminal the potential change is Positive

42 The resistance of a conductor is directly proportional to :
A. Length
B. Area
C. volt
D. current
Ans: A
The resistance of a conductor is directly proportional to length

43 Which of the following laboratory apparatus is used during the verification of Ohm’s law ?
A. Voltmeter
B. Ammeter
C. Rheostat
D. All the above
Ans: D

44 Positive electrode is known as__________.
A. Cathode
B. Anode
C. Anode tube
D. Cathode tube
Ans: B

45 When the pointer of an analog ohmmeter reads close to zero, the resistor being measured is:
A. open
B. reversed
C. shorted
D. overheated
Ans: C
r=0 when short circuited
r=infinity(high) when open circuited.

Must Read: 115 Solved MCQs on Electricity