Electricity

ELECTRICITY

VERY SHORT ANSWER TYPE QUESTIONS (SAQ)

1. Name the physical quantity expressed as the product of potential difference and electric current. Answer : Elect...

SHORT ANSWER TYPE QUESTIONS (SAQ)

1. Why do copper or aluminium wires usually used for electricity transmission and distribution purposes?...

2. Why are coils of electric heaters and electric irons made of an alloy rather than a pure Metal? Answer : Alloys...

3. Define resistance. Give its SI unit. Answer : Resistance of a conductor is the measure of opposition offered b...

4. Mention the condition under which charge can move in a conductor. Name the device which is used to maintain this cond...

5. List the factors on which the resistance of a conductor depends. Write the expression to show the relation of resista...

6. Answer the following questions: (i) Define resistance of a conductor. (ii) State Ohm's law. (iii) State Joule's law o...

7. Answer the following questions: (i) What is an ammeter? (ii) What is a voltmeter? (iii) Define resistivity. Answe...

8. Why are copper and aluminium wires used as connecting wires? Answer : Copper and aluminum wires are chosen for...

9. Name a material which is used for making standard resistors. Give a reason for your answer. Answer : Standard re...

10. Why is a series arrangement not used for domestic circuits? Answer : Series arrangement is not used for domesti...

11. Answer the following questions: (i) List the factors on which the resistance of a conductor in the shape of wire dep...

12. Why is lead-tin alloy used for fuse wires? Answer : Lead-tin alloy is chosen for fuse wires because it has a l...

13. Which of the cables, one rated 5 A and the other 10 A will be of thicker wire? Give a reason for your answer. An...

14. Why are the heating elements of electric toasters and electric irons made of an alloy rather than a pure metal?...

15. What is commercial unit of electrical energy ? Express it in joules. Or...

16. Why is tungsten used for filaments of electric lamps? Answer : Tungsten is used in electric lamp filaments bec...

17. Answer the following questions: Define electric power. (ii) What is a super conductor? Give two examples. (iii) What...

18. Two wires P and Q are made of copper. The wire P is long and thin, while the wire Q is short and thick. Which will h...

19. Two identical immersion heaters are to be used to heat water in a large container. Which one of the following arrang...

20. What is an electric circuit ? Distinguish between an open and a closed circuit. Answer : electric circuit: 1....

21. What do the following symbols represent in a circuit ? Write the name and one function of each. [picture] Answe...

22. Should the heating element of an electric iron be made of iron, silver or nichrome wire 1...

23. Why should a connection wire be thick? Answer : The resistance of a wire gets lower as its thickness, or cross-...

24. Why is the tungsten used almost exclusively for filament of electric lamps ?...

25. . State Joule’s law of heating. Answer : A s per Joule’s law the heat produced in a resistor is (i) directly...

26. Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason. Ans...

27. (a) What do you mean by resistance of a conductor? Define its unit. (b) In an electric circuit with a resistance wir...

28. (a)Define electric power. Express it in terms of V, I and R where V stands for potential difference, R for resistanc...

29. In an electric circuit, state the relationship between the direction of conventional current and the direction of fl...

30. What is meant by the statement “potential difference between points A and B in an electric field is 1 volt”?...

31. Define kW h. Answer : A kilowatt-hour (kWh) is the standard unit of electricity you use in your home. It's th...

32. Two electric bulbs A and B are marked 220V, 40W and 220 V, 60W respectively. Which one of the two has greater resist...

33. On what factors does the resistance of a conductor depend? Or List the factors on which the resistance of a conducto...

34. Define an electric circuit. Draw a labelled, schematic diagram of an electric circuit comprising of a cell, a resist...

36. In the circuit diagram shown, the two resistance wires A and B are of same area of cross-section and same material,...

37. (a) Establish a relationship to determine the equivalent resistance R of a combination of three resistors having res...

38. Two students perform experiments on two given resistors R1 and R2 and plot the following V-I graphs. If R1 > R2, whi...

39. Two wires, one of copper and other of manganin, have equal lengths and equal resistances. Which wire is thicker ? Gi...

40. What is likely to happen and how it would affect the value of resistance if we pass the current for a longer time ?...

41. List two distinguishing features between the resistance and resistivity of a conductor. Answer : The resistan...

42. (a) Why an ammeter likely to bum out if you connect it in parallel ? (b) Why is series arrangement not found satisfa...

43. An electric lamp of resistance 20 Ω and a conductor of resistance 4 Ω are connected to a 6 V battery as shown in the...

45. (a) n electrons, each carrying a charge -e, are flowing across a unit cross-section of a metallic wire in unit time...

46. What is heating effect of electric current? Find an expression for amount of heat produced. Name some appliances bas...

LONG ANSWER TYPE QUESTIONS (LAQ)

1. How will you conclude that the same potential difference (voltage) exists across three resistors connected in a paral...

2. What is electrical resistivity of a material? What is its unit? Describe an experiment to study the factors on which...

3. How will you infer with the help of an experiment that the same current flows through every part of the circuit conta...

4. Three incandescent bulbs of 100 W each are connected in series in an electric circuit. In another set, three bulbs of...

5. What is Joule's heating effect? How can it be demonstrated experimentally? List its four applications in daily life....

Page 172 1. What does an electric circuit mean? An electric circuit is a closed and continuous...

Page 174 1. Name a device that helps to maintain a potential difference across a conductor. A c...

Page 181 1. On what factors does the resistance of a conductor depend? The resistance of a cond...

Page 185 1. Draw a schematic diagram of a circuit consisting of a battery of three cells of 2 V each, a 5 Ω...

Page 188 1. Judge the equivalent resistance when the following are connected in parallel: (a) 1 Ω and 10⁶ Ω,...

Page 188 3. What are the advantages of connecting electrical devices in parallel with the battery instead of...

Page 188 4. How can three resistors of resistances 2 Ω, 3 Ω, and 6 Ω be connected to give a total resistance...

Page 188 5. What is (a) the highest, (b) the lowest total resistance that can be secured by combinations of f...

Page 190 1. Why does the cord of an electric heater not glow while the heating element does? Th...

Page 192 1. What determines the rate at which energy is delivered by a current? The rate at whi...

Page 193 - Exercises (Questions 1 to 3) 1. A piece of wire of resistance R is cut into five equal p...

Page 193 - Exercises (Questions 4) 4. Two conducting wires of the same material and of equal length...

Page 193 - Exercises (Question 5) 5. How is a voltmeter connected in the circuit to measure the pot...

Page 193 - Exercises (Question 6) 6. A copper wire has a diameter of 0.5 mm and a resistivity of...

Page 193 - Exercises (Question 8) 8. When a 12 V battery is connected across an unknown resistor, t...

Page 193 - Exercises (Question 9) 9. A battery of 9 V is connected in series with resistors of...

Page 193 - Exercises (Question 10) 10. How many 176 Ω resistors (in parallel) are required to carry...

Page 193 - Exercises (Question 11) 11. Show how you would connect three resistors, each of resistan...

Page 193 - Exercises (Question 12) 12. Several electric bulbs designed to be used on a 220 V electr...

Page 193 - Exercises (Question 13) 13. A hot plate of an electric oven connected to a 220 V line ha...

Page 193 - Exercises (Question 14) 14. Compare the power used in the 2 Ω resistor in each of the fo...

Page 194 - Exercises (Question 15) 15. Two lamps, one rated 100 W at 220 V, and the other 60 W at 2...

Page 194 - Exercises (Question 16) 16. Which uses more energy, a 250 W TV set in 1 hour,...

Page 194 - Exercises (Question 17) 17. An electric heater of resistance 44 Ω draws 5 A fr...

Page 194 - Exercises (Question 18) 18. Explain the following: (a) Why is tungs...