MCQ on current electricity for class 12 CBSE PDF

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In recent exam pattern of class 8, 10 and 12, MCQ and short questions carry majority marks. In this context multiple choice questions are very much important to secure a good score in exams. Students need to find MCQs from the textbooks. But most of the students fail to gather majority of inside questions. Therefore, I am providing almost all the MCQ on current electricity for class 12 CBSE, NEET, JEE and all other board exams. These multiple choice questions on current electricity will be helpful for class 10 CBSE students too.

CBSE class 12 chapter 3 : Current electricity

MCQ questions for class 12 physics chapter 3 on current electricity with answer in PDF format.

MCQ on Current Electricity

1. Ohm’s law of current electricity is not applicable for

  1. Resistor
  2. Diode
  3. Capacitor
  4. Inductor

See the concept of linear and non-linear circuit components – Resistor, Capacitor, Inductor, Diode and Transistor.

2. Which of the followings has non-ohmic resistance?

  1. Carbon resistance
  2. Filament of lamp
  3. Diode
  4. Copper wire

Non-linear elements have non-ohmic resistance. Ohm’s law are not applicable for these type of circuit elements.

3. You have four resistors each of 2 ohm resistance. The maximum resistance you can obtain from the combination of these resistors is

  1. 8 ohm
  2. 4 ohm
  3. 2 ohm
  4. 16 ohm

One can obtain maximum resistance by connecting these resistors in series combination.

4. You have four resistors each of 2 ohm resistance. The minimum resistance you can obtain from the combination of these resistors is

  1. 4 ohm
  2. 0.5 ohm
  3. 6.5 ohm
  4. 8 ohm

One can obtain minimum resistance by connecting those resistors in parallel combination.

5. The ratio of series combination to parallel combination of two equal resistances is

  1. 2 : 1
  2. 1 : 1
  3. 4 : 1
  4. 1 : 4

6. A, B and C are voltmeters of resistance R, 1.5R and 3R respectively. When some potential difference is applied across X and Y, then voltmeter readings VA, VB and VC are related as

  1. VA=VB=VC
  2. VA=VB\small \neqVC
  3. VA \small \neqVB=VC
  4. VA\small \neqVB\small \neqVC

7. A wire of resistance 4 ohm is stretched to twice its original length. The resistance of stretched wire would be

  1. 4 ohm
  2. 8 ohm
  3. 2 ohm
  4. 16 ohm

Note that, the resistance will not be 8 ohm. Because on increasing in length its cross-section area decreases to maintain constant volume. Then the answer will be 16 ohm.

8. A uniform circular wire has total resistance of 10 ohm. The equivalent resistance across its diameter is

  1. 10 ohm
  2. 2.5 ohm
  3. 5 ohm
  4. 7.5 ohm

Upper half and lower half of the circle will have 5 ohm resistance each. So, here two 5 ohm resistances are in parallel combination. Hence, the equivalent resistance across the diameter is 2.5 ohm.

9. Resistivity of a conductor depends on

  1. Length of the conductor
  2. Cross-section area of the conductor
  3. Temperature of the conductor
  4. all of these

Resistivity is the property of material. It depends on the Temperature and the type of material.

10. SI unit of resistivity is

  1. Ohm
  2. Ohm.m
  3. Ohm/m
  4. mho/m

11. Kirchhoff’s current law (KCL) consequences

  1. Law of conservation of charge
  2. Conservation of angular momentum
  3. Law of conservation of energy
  4. do not obey any conservation law

12. Kirchhoff’s voltage law (KVL) obeys

  1. Law of conservation of charge
  2. Law of conservation of energy
  3. Conservation of current density vector
  4. Conservation of angular momentum

Check the article on Kirchhoff’s law (KCL and KVL).

13. A conducting wire has resistance R. If its length is doubled and radius is halved simultaneously, then its new resistance will be

  1. 2R
  2. 4R
  3. 8R
  4. R/2

14. A Galvanometer will act like a voltmeter if its coil is connected with a

  1. High resistance in parallel
  2. High resistance in series
  3. Low resistance in parallel
  4. Low resistance in series

15. A Galvanometer will act like a ammeter if its coil is connected with a

  1. High resistance in Series
  2. High resistance in parallel
  3. Low resistance in series
  4. Low resistance in parallel

16. 1 volt is equal to ______________ StatVolt

  1. 300
  2. 1/300
  3. 500
  4. 900

17. A 5 ampere fuse wire can withstand a maximum power of 1 watt in a circuit. Then the resistance of the fuse wire is

  1. 0.2 ohm
  2. 0.4 ohm
  3. 0.04 ohm
  4. 0.02 ohm

Electric power, P=I2R.

18. 1 BOT = _____________ Joule?

  1. 3.6
  2. 3600
  3. 36×105
  4. 0.36×106

19. The unit of temperature co-efficient of resistance is

  1. °C
  2. °C-1
  3. Ohm.°C
  4. Ohm/ °C

20. Copper wire is commonly used as connecting wire because

  1. copper has high electrical resistivity
  2. It has low electrical resistivity
  3. copper has low electrical conductivity
  4. It has high elasticity

An ideal connecting wire should have zero resistance.

21. In the following circuit, the current through the resistance R will be zero if

  1. 2 ohm resistance is connected in series with 1 ohm resistance.
  2. 1 ohm resistance is connected with one of the 2 ohm resistance
  3. 1 ohm resistance is connected in parallel of 3 ohm resistance
  4. resistance of R is made 1 ohm

22. In the above circuit, if R is opened then what will be the equivalent resistance between a and b?

  1. 1 ohm
  2. 4 ohm
  3. 2 ohm
  4. 1.87 ohm

23. In a Wheatstone bridge, the resistance each arm is 5 Ω. If the resistance of the galvanometer is 4 Ω, then effective resistance of the bridge will be

  1. 5 ohm
  2. 10 ohm
  3. 2.5 ohm
  4. 9 ohm

24. A Wheatstone bridge has resistances 10 ohm, 10 ohm, 10 ohm and 30 ohm in its four arms. What resistance is to be connected in parallel to 30 ohm resistance so that the bridge be balanced?

  1. 10 ohm
  2. 15 ohm
  3. 20 ohm
  4. 30 ohm

25. Electric energy consumed by a 100 W lamp used for 8 hours is

  1. 100 J
  2. 6400 J
  3. 12.5 J
  4. 800 J

Electrical energy = electrical power × time

26. The SI unit of electrical conductance is

  1. Ohm
  2. Ohm.m
  3. Siemens (S)
  4. A.s

Siemens is the inverse of Ω. It is also known as mho.

27. A two ohm resistor is connected in series with a six ohm resistor and then entire combination is connected with an eight ohm resistor. The equivalent resistance of the combination of these three resistors is

  1. 8 ohm
  2. 4 ohm
  3. 2 ohm
  4. 12 ohm

28. If n cells each of EMF E and internal resistance r are connected in parallel, then the total EMF and the internal resistance of equivalent cell will be

  1. E and nr
  2. nE and nr
  3. E and r/n
  4. nE and r

29. A fuse wire should have

  1. High resistivity and low melting point
  2. low resistivity and high melting point
  3. High resistivity and high melting point
  4. low resistivity and low melting point

30. In the following circuit, if a 10 volt battery is connected across X and Y, then what will be the current through 20 ohm resistance?

  1. 2 Ampere
  2. 10 Ampere
  3. 15 Ampere
  4. zero

This is a simple Wheatstone bridge circuit. It is in balanced condition. So, there will be no current through the 20 ohm resistance.

31. In the above circuit, what is the equivalent resistance between the points X and Y?

  1. 20 ohm
  2. 10 ohm
  3. 15 ohm
  4. 5 ohm

According to Wheatstone bridge principle, the 20 ohm resistance at the middle will be ineffective. So, one can open that resistance.

32. Which of the following is not the unit of electric bill?

  1. kW.h
  2. B.O.T.
  3. Watt
  4. Joule

Electric bill is calculated with respect to the loss in energy, not by power. Here, kW.h, B.O.T, and Joule are the units of electrical energy and watt is the unit of electrical power.

33. The internal resistance of a 2.1 volt cell which gives a current of 0.2 A through a resistor of 10 ohm is

  1. 0.8 ohm
  2. 0.5 ohm
  3. 1.0 ohm
  4. 0.2 ohm

This is all from the MCQ on current electricity of class 12 chapter 3. This article covered most of the MCQ on current electricity of previous year question paper of CBSE, JEE, NEET and NCERT. If you have any other question related to this topic you can ask me in the comment section.

Thank you!

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