Welcome to your Current Electricity MCQs Mock Test of Class 12th Physics

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Question 1. What is the resistance across A and B in the network in Fig.?

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Question 2. When the wires are connected in parallel, the heat produced in the thinner wire is H1 and that in the thicker wire is H2 Then:

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Question 3. Two equal resistors are connected in series across a battery and consume a power of P. If these are connected in parallel, then the’ power consumed will be:

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Question 4. Thermo electricity was discovered by:

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Question 5. Thermo emf is the order of:

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Question 6. How many different resistances are possible with two equal resistors?

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Question 7. Given three equal resistors, how many different combinations (taken all of them together) can be made?

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Question 8. Specific resistance of ali metals is mostly affected by:

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Question 9. The example of a non-ohmic resistance is:

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Question 10. If a certain piece of copper is to be shaped into a conductor of minimum resistance, its length (L) and cross-sectional area (a) shall respectively be :

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Question 11. The specific resistance of a rod of copper as compared to that of thin wire of copper is :

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Question 12. A wire of resistance 3 Ω is cut into three pieces, which are then joined to form a triangle. The equivalent resistance between any corners of the triangle is :

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Question 13. The length of a conductor is halved. Its resistance will be :

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Question 14. In the above question, the conductance:

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Question 15. Siemen is the unit of:

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Question 16. How much electric energy is consumed by a 100 W lamp used for 6 hours everyday for 30 days?

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Question 17. Suppose H1 is the heat generated per second in the filament of a 100 W, 250 V lamp and H2 is the heat generated in the filament of a 200 W, 250 V lamp. Then H1/H2 is equal to:

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Question 18. Two wires of copper are of the same length but’have different diameters. When they are connected in series across a battery, the heat generated is H1 When connected in parallel across the same battery, the heat generated during the same time is H2 Then :

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Question 19. The speed at which tjie current travels in a conductor is nearly:

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Question 20. The resistance of a human body is about:

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Question 21. The number of electrons that constitute 1 A of current is:

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Question 22. In questions 135, w hen the wires are connected in series, the heat produced in the thinner wire is H1 and that in the thicker wire is H2. Then :

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Question 23. Kirchhoffs first and second laws for electrical circuits are consequences of:

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Question 24. A 5 A fuse wire can with stand a maximum power of 1 W in circuit. The resistance of the fuse wire is:

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Question 25. A galvanometer acting as a volt meter will have with its coil.

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Question 26. When three identical bulbs of 60 W, 200 V rating are connected in series to a 200 V supply, the power drawn by them will be:

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Question 27. n resistances, each of R Ω, are connected in parallel gives an equivalent resistance of R Ω. If these resistances were , connected in series, the combination would have a resistance in Ω is equal to

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Question 28. Why is the Wheatstone bridge more accurate than other methods of measuring resistances: ‘

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Question 29. A potential difference of 10 V is applied across a conductance of 2 S. The current in the conductor will be :

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Question 30. Ohm’s law is valid when the temperature of conductor is :

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Question 31. The emf of a car battery is about:

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Question 32. Emf is measured in :

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Question 33. 1 kilowatt hour is commonly known as :

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Question 34. How many joules are equal to I kWh ?

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Question 35. The temperature coefficient of resistance is expressed in :

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Question 36. Copper wire is used as connecting wire because :

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Question 37. The heat sensitive device whose resistivity changes very rapidly with change of temperature is called a :

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Question 38. The phenomenon of super-conductivity was discovered by :

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Question 39. The specific resistance of a conductor increases with :

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Question 40. In an experiment with potentiometer, null point with a cell is found at 240 cm. When the cell is shunted with a resistance 2 Ω, the null point becomes 120 cm internal resistance of cell is :

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Question 41. Two conductors of equal length and radii the ratio of 2 : 3 are; connected in parallel the source of electricity. The ratio of the velocity of electrons in the conductor be :

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Question 42. The charge flowing in a conductor varies with time as : q = αt 12 βt² + 16 γt³ Where α, β, γ are positive constants. Then the initial current (l) is given by the condition :

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Question 43. In questions 38, the maximum value of current (lmax) is given by the condition :

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Question 44. In questions 38, the line (t) after which the value of current reaches a maximum values given by :

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Question 45. In following figure shows currents in a part of electrical circuit, then the value of/(in ampere) is given by :

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Question 46. The smallest resistance that can be obtained by the combination of n resistors each resistance r is :

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Question 47. Which of the following has a negative temperature coefficient of resistance ?

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Question 48. An electric heating element consumes 500 W, when connected to a 100 V line. If the line voltage becomes 150 V, the power consumed Will be:

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Question 49. A uniform w ire connected across a supply produces heat H per second. If wire is cut into three equal parts and all the parts are connected in parallel across the same supply, the heat produced per second will be :

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Question 50. In India electricity is supplied fordomestic use at 220 V. It is supplied at 110 V in U.S.A. If the resistance of a 60 W bulb use in India is R. the resistance of a 60 W bulb for use in USA will be: