Current Electricity Class 12 MCQ: Class 12 Physics MCQ Questions and Answer. Students get here all Important MCQ on Current Electricity Class 12.
Current Electricity Class 12 MCQ with Answers:
Multiple choice questions
1.) If a net charge ∆Q passes through any cross section of a conductor in time ∆t, then the electric current I will be.
a)∆Q/∆t.
b)∆t/∆Q
c) ∆Q/t.
d)∆Q×∆t
Ans : a) ∆Q/∆t
2.) The SI unit of current is
a) volt.
b) ampere
c) Coulomb/metre.
d)meter /Coulomb
Ans : b) ampere
3.) One ampere can be expressed as
a) Coulomb/metre.
b) Coulomb/volt.
c) Coulomb/second.
d) Coulomb metre
Ans : c) Coulomb/second
4.) Is it current flow unidirection or multidirection in single wire.
a)unidirection.
b) multidirection
c) direction less.
d) Non of these
Ans : a) unidirection.
5.) In a metal, the valence electrons are not attached to individual atoms but are free to move about within the body. These electrons are known as.
a) Individual electrons.
b) Free electrons
c) Random electrons
d) like electrons
Ans : b) Free electrons
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6.) Fill in the blank.
Electric generators are converte _____ energy into electric energy.
a) chemical.
b) mechanical
c) heat.
d) solar
Ans : b) mechanical
7.) Fill in the blank.
Cells ( primary as well as secondary) are convertes _____ energy into electric energy.
a) chemical
b) mechanical
c) heat.
d) solar
Ans : a) chemical
8.) Thermo couples are converte _____ energy into electric energy.
a) chemical.
b) mechanical
c) heat.
d) solar
Ans : c) heat
9.) Solar cells are converte ______ directly into electric energy.
a) water.
b) sunlight
c) air.
d) earth
Ans : b) sunlight
10.) The heat H produced by a current I in the wire of resistance R during a time interval t, then it can be written as.
a)H = I2Rt.
b) R= IH2t
c) I = H2
d) t = I2Ht
Ans : a) H = I2Rt
11.) The liquid which conducts current is known as
a)liqueolyte.
b) electrolyte
c) conductolyte.
d) liquefied current
Ans : b) electrolyte
12.) The material in the form of wire or rod or plate which leads the current into or out of the electrolyte is known as.
a)electrode.
b) metaloids
c) liqueoloide.
d) electrometal
Ans : a) electrode.
13.) If the electrode connected with the positive terminal of the current source then it is known as.
a) cathode.
b) anode
c) positive source.
d) negative source.
Ans : b) anode
14.) If the electrode connected with the negative terminal of the current source then it is known as.
a) cathode.
b) anode
c) positive source.
d) nagetive source.
Ans : a) cathode
15.) The vessel contaning the two electrodes and the liquid is known as.
a) voltmeter.
b) voltameter
c) ammeter.
d) galvanometer.
Ans : b) voltameter
16.) Complete the reaction.
Cu++ + ______ → CuSo
a)SO4– –.
b) SO4++
c) SO4+-
d) SO4
Ans : a) SO4– –
17.) Symbolically Ohm’s law can be written as.
a) V= RI.
b) I = VR
c) R= VI.
d) I = R/V
Ans : a) V = RI
18.) Fill in the blank.
” The current flowing through a conductor is directly proportional to the _____ across its ends of provided the physical state such as temperature etc of the conductor remains constant.
a) potential difference.
b) current
c) electron.
d) resistance
Ans : a) potential difference
19.) One Ohm can be expressed as.
a) meter/ ampere.
b) ampere/ second
c) ampere / volt.
d) volt/ ampere
Ans : d) volt / ampere
20.) A conductor which strictly obeys Ohm’s law is called.
a) Ohmic.
b) non Ohmic
c) semiconductor.
d) diodes
Ans : a) Ohmic
21.) The graph of current v/s voltage is not have a straight line then such a diode is known as.
a) Non electric device.
b) Non Ohmic device
c) Ohmic device
d) Non of these.
Ans : c) Ohmic device.
22.) The formula for equivalent resistance where resistores are connected in series.
a) Req = R1+R2+R3……..
b) Req = (1/R1)+(1/R2)+(1/R3)+………
c) 1/Req = R1+R2+R3+………
d) 1/Req = (1/R1)+(1/R2)+(1/R3)+…..
Ans : a) Req = R1+R2+R3……..
23.) The formula for equivalent resistance where resistores are connected in parallel.
a) Req = R1+R2+R3……..
b) Req = (1/R1)+(1/R2)+(1/R3)+………
c) 1/Req = R1+R2+R3+………
d) 1/Req = (1/R1)+(1/R2)+(1/R3)+…..
Ans : d) 1/Req = (1/R1)+(1/R2)+(1/R3)+…..
24.) If R is a resistore of wire of length L and A be the area of cross section then relationship between them can be expressed as.
a)R = ρ(L/A).
b) R = ρ(A/L)
c) L = ρRA.
d) A = ρLR
Ans : a)R = ρ(L/A).
25.) SI unit of resistivity is.
a) Ohm/meter.
b) Ohm.meter
c) meter/sec.
d) Ohm/Coulomb
Ans : b) Ohm.meter
26.) Conductance can be expressed as.
a)1/resistance.
b) resistance/2
c) Area/resistance.
d) resistance/Area
Ans : a) 1/ resistance
27.) SI unit of conductivity is
a) Ohm-1m-1
b) Ohm.m
c) Ohm.m-1
d) m.Ohm-1
Ans : a) Ohm-1m-1
28.) Complete the formula.
α = (Rt – Ro)/____
a) Rt + Ro
b) RtRo
c) (Rt + Ro )t
d) Rot
Ans : d) Rot
29.) In colour code of a carbon resistores, which band gives the number of zero after the first two digits.
a) First band
b) second band
c) Third band.
d) Fourth band
Ans : c) Third band
30.) In colour code of a carbon resistores, which band gives resistance tolerance.
a) First band.
b) Second band
c) Third band.
d) Fourth band
Ans : d) Fourth band.
31.) An heat sensitive resistor is also known as.
a) Thermistor.
b) Galvanometer
c) Rheostat.
d) Resistance box
Ans : a) Thermistor
32.) Electric power can be expressed as.
a.) Energy supplied/Time taken
b) Potential difference/ Energy supplied
c) Change / Energy
d) Time taken / Energy supplied
Ans : a) Energy supplied / Time taken
33.) The work done in moving a charge ∆Q up through the potential difference V is given by.
a) ∆W = V×∆Q
b) ∆W = ∆V×∆Q
c) ∆W = ∆V×Q
d) ∆W = V/∆Q
Ans : a) ∆W = V×∆Q
34.) If V is potential difference and R be the resistance and P be the power dissipated in a resistor then the relation between V,P and R is .
a) P = V2/R. b) P = V/R
c) P = V/R2. d) P = V2/R2
Ans : a) P = V2/R
35.) In generally Power can be expressed as.
a) Volt b) Watt
c) Coulomb / Volt. d) Volt / Watt
Ans : b) Watt
36.) The unit of electromotive force (EMF) is
a) Joules/Coulomb
b) Coulomb/volt
c) Coulomb/Joules
d) Volt/ Coulomb
Ans : a) Joules/Coulomb
37.) If E is EMF and r be the internal resistance, R is the external resistance and I be the current flow through the circuit then the relation between E,R,r, and I is .
a) E = I(R+r)
b) E = I(R-r)
c) E = (R+r)/I
d) E = I /(R+r)
Ans : a) E = I(R+r)
38.) Kirchhoff’s first rule state that the sum of all the current meeting at a point in the circuit is_____
a) zero.
b) one
c) Infinite.
d) -one
Ans : a) zero
39.) Kirchhoff’s second rule state that the algebraic sum of potential charges in a closed circuit is.
a) zero.
b) one
c) -one.
d) Infinite
Ans : a) zero
40.) If a source of emf is traversed from negative to positive terminal, the potential charge is ________
a) Positive.
b) Nagetive
c) Opposite direction.
d) Multi direction
Ans : a) Positive
41.) If a resistore is traversed in the direction of current, the change in potential is _______
a) Positive.
b) Nagetive
c) Opposite direction.
d) Multi direction
Ans : b) Nagetive
42.) The final equation of Wheatstone bridge.
a)R1/R2=R3/R4
b) R1/R2=R4/R3
c) R2/R1=R3/R4.
d) R2/R3=R1/R4
Ans : R1/R2=R3/R4
43.) Commonly voltmeter is used to measure.
a) Difference of current
b) Potential difference
c) Resistance
d) Energy
Ans : b) Potential difference
44.) If l1 and l2 are lengths of the two cells and E1 and E2 be the emf of the cells ,then
a)E1/E2=l2/l1. b)E1/E2=l1/l2
c)E1×E2=l2×l1. d)E1=E2×l2×l1
Ans : b)E1/E2=l1/l2
45.) The maximum Power output, P = ER/____
a) (R+r)2
b) (R1+r2)
c) (R12+r)
d) (R+r)
Ans : a) (R+r)2
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