Test & answers of electrical

 Test & answers of electrical

1. What exactly is electricity?

2. What other sorts of electricity are there?

3. Why does static electricity exist?

4. What is electricity in use today?

5. What different types of electricity are there today?

6. What are the various ways that power is produced? Give instances.

7. What sources of electricity are there?

8. What are some uses for electricity?

9. What impacts does electricity have?

10. Describe A.C. and D.C.

11. Where is the term D.C. used?

12. Where does A.C. get used?

13. How will you determine whether the supply in the premises is AC or DC?

14. What are conductors, exactly?

15. What exactly are insulators?

16. What substances are typically employed as conductors?

17. What types of materials are typically employed as insulators?

18. What phrase is used to compare the various insulation types?

19. What does "Dielectric strength" mean? 19.

20. What are the variables that affect the dielectric strength?

21. What impact does heat have on insulators?

22. How do contaminants and moisture affect insulating materials?

23. Why are porcelain tiles used as external insulators glazed?

24. What characteristics define a good conductor?

25. What characteristics make a good insulator?

26. What exactly are semiconductors?

27. What varieties of semiconductors are there?

28. Give a few instances of semiconductors in number 

29. Where are semiconductors used, number 29?

30. What is resistance, exactly?

31. How are resistances categorized?

32. What is the measurement of resistance?

33. What exactly is a resistor?

34. What variables affect a conductor's resistance?

35. What is a conductor's particular resistance?

36. What is the specific resistance unit?

37. What relationship exists between resistance, length, and cross-sectional area?

38. What impact does heat have on resistance?

39. What is the definition of the temperature coefficient of resistance?

40. What is Ohm's law?

41. Ohm's law expresses what basic relationship?

42. List the three Ohm's law equations.

43. Can Ohm's law apply to every kind of electrical conductor?

44. A bulb is connected to a 10V battery, and a current of 0.01 A is measured. The continuous current through the bulb, when connected to 220V mains, is 0.05A. Justify this seeming inconsistency with Ohm's law.

45. What are the restrictions on Ohm's law?

46. What is an electrical circuit, exactly? What kinds are there?

47. Describe the term "closed circuit."

48. What do you mean by an open circuit?

49. How do you define a short circuit?

50. What resistance combinations are there?

TEST 1 ANSWERS

1. All phenomena induced by electric charge, either static or in motion, are collectively called electricity.

2. Static electricity and current electricity are the two types.

3. Electricity at rest is referred to as static electricity, as opposed to dynamic and current electricity, whose effects are solely a result of the electrostatic field created by the charge. Frictional electricity is another name of it.

4. The term "current electricity" refers to electricity that is in motion and whose effects result from the movement of electrons.

5. Direct current and alternating current are the two types.

6. The techniques are as follows:

i) Static electricity is created by friction.

ii) Through chemical reactions that take place in cells.

iii) Through mechanical driving.

iv) Using heat.

v) Using the illumination.

7. Thermocouple, battery, and generator are in that order.

8. Heating, lighting, welding, operating motors.

9. Physical effects include electric shock, heating effects, fuses, magnetic effects ,electric bells, chemical effects and X-ray effects.

10. A.C. stands for alternating current, which is a current that periodically flows in and out of a circuit in opposite directions with regular variations in magnitude. D.C. stands for direct current, which only flows in one direction.

11.) 1.) Battery charging; 2.) Electroplating; 3.) Electrolysis.

12.) 1.)Household appliances; 2.) Fans; 3.) Refrigerators.

13.) Observe the connection between a fan and a tube light.

14. Conductors are metallic materials with many free electrons and little resistance to the flow of electricity through them. 

15. Insulators are nonmetallic materials with comparatively few free electrons and a lot of resistance that prevents electricity from flowing through them.

16. Copper, Aluminum, Brass,

17. Mica, oiled paper, vulcanized rubber, and mica

18."Dielectric Strength."

19. The upper limit of kilovolts per millimeter that an insulating material can endure without breaking down is known as the dielectric strength.

20. The following variables affect the dielectric strength.

  the specimen's thickness, the size and shape of the electrodes used to apply the stress, the dispersion of the electric stress field within the material and the voltage's applied frequency.

21. With the probable instance of mica and asbestos, the insulation resistance of most solid dielectrics increases when heated and decreases when chilled.

22. The combined effects of moisture and contaminants on an insulating material lower its resistivity, increase absorption and dielectric loss and ultimately weaken the dielectric strength.

23. Outdoor porcelain insulators are glazed to avoid surface leakage caused by dirt and moisture absorption. Glazing also increases insulating resistance.

24. A good conductor must possess the following qualities: i) less resistivity; ii) Less change in resistance

In a good insulator: - not capable of absorbing moisture,

High corrosion resistance, strong mechanical properties,

26. A substance is referred to as a semiconductor if its resistance falls between that of an insulator and a good conductor. As the temperature rises and more impurities are present, its resistance reduces.

27. Semiconductors come in two varieties: pure intrinsic and extrinsic semiconductors with additional impurities.Extrinsic semiconductors can be separated into N-type and P-type kinds based on the sort of impurity that has been added.

28. Examples are carbon (C), silicon (Si), germanium (Ge), and selenium (Se).

29. Semiconductors are typically employed in electronic equipment, including radios, televisions and VCRs.

30. A substance's ability to resist the passage of electricity throughout it is referred to as resistance.

31. Resistances are categorized in the following ways according to where they were measured:

 Low resistances =ohm or less.

 Medium resistances =1 ohm to 100 000 ohms.

High resistances =of 100,000 ohms or more.

32.'Ohm' is the name of the resistance unit.

33. A device known as a resistor has as its primary function the ability to oppose or impede the flow of electrical current.

34. A conductor's resistance is determined by its (1) Length, (2) Cross Section, (3) Resistivity, (4) Temperature, and (5) Type of current passing through it.

35. The resistance provided by a unit meter cube of a conductor's material is known as its specific resistance, also known as resistivity.

36. Ohm-meter.

37. Resistance Length / (Area of Cross Portion) Resistance fluctuates and is inversely correlated with cross-section and directly correlated with length.

38. As temperatures rise, resistance increases, and as temperatures fall, resistance decreases.

39. The variation in resistance per degree change in temperature per Ohm of resistance is known as the temperature coefficient of resistance.

40. According to Ohm's law, the current flowing through a circuit inversely corresponds to the probable difference along the circuit when the temperature is constant.

41. Ohm's law, as stated I = V/R, explains how a circuit's voltage, current, and resistance interact.

42. I equals E/R, R equals E/I, and I equals E/R. I = I.R. I stands for the current flow in amperes, R for resistance in ohms, and E for electromotive force in volts.

43. No. Only in situations involving conductors through metal and electrolytic conduction can Ohm's law be used. It is not apply when conducting via semiconductors or ionized gases.

44. Once the bulb is hooked to a 220V mains outlet, the filament's temperature rises, increasing resistance. Consequently, we have a violation of the law.

45. Vacuum tubes, discharge tubes, and semiconductors are examples of non-ohmic conductors that are not covered by Ohm's law.

46. An electric circuit is an entire channel that electric current can travel along and comprises a power source & connecting wires. 

47. Closed circuit is an electric circuit that is fully functional throughout which current flows when voltage is supplied.

48. A recess in a circuit is referred to as an open or broken circuit if it lacks an entire route or circuit allowing the movement of electric current.

49. A short circuit is a mistaken connection with very little resistance that joins two wires of a circuit with different polarities, through which almost all of the current will flow.

50. There are three ways to combine different types of resistance: series, parallel, and series-parallel mixed.