About Impedance

Like all things in the universe, there are certain constants that have been defined by scientists to define various concepts and phenomena. Impedance is one of these constants, and it has been defined as the resistive opposition to the flow of alternating current in an AC circuit. This means that impedance—or Z—is essentially a measure of how difficult it is to transfer electrical energy across an AC circuit.

The term impedance is derived from a Latin word meaning resistance. In electrical engineering, it is a measure of opposition to current flow. There are two types of impedance — referred to as internal impedance and source impedance. The total impedance of a circuit is equal to the summation of its individual impedances. This means that if you have multiple resistors in series or parallel in a circuit, their combined values will determine overall impedance. For example, if you have three resistors with values of 1 ohm each in series, then their combined value will be 3 ohms. If those same three resistors were placed in parallel, they would add up to 1 ohm again.

What Are The Most Common Types of Impedance?

In electrical engineering, impedance is a measure of resistance to current flow. It has units of ohms, which is a measure of voltage over current. Impedance also determines how much voltage or power will be lost across a circuit, as well as how much energy is absorbed by a circuit when it’s carrying currents and voltages in certain directions.

Following are some of the multiple choice questions on the Impedance with answers that will help the students in developing their knowledge.

Impedance MCQ

1. What unit is a capacitor measured in?

  • Ohms
  • Henrys
  • Farads
  • Amps

2. 5∠150° 10∠−60°Determine in rectangular form

  • -1.73
  • -1.73+j
  • 1.73+j
  • -j2

3. 2∠45°×3∠135° Determine in polar forms

  • -6
  • 6∠180°
  • 6
  • 6-j180

4. 2+j10 7−jDetermine the answer in rectangular forms

  • 0.04−j0.69
  • 0.69 -86.82 
  • 6.9-j0.02
  • 7-j9.5

5. Convert to polar:−4+j4

  • 5.65
  • 5.65∠45°
  • 5.65∠135°
  • -4

6. Identify the voice track

  • stephen
  • hawking
  • Both A & B
  • none of the above

7. NK cells lack cell makers except

  • CD3
  • CD4
  • CD8
  • CD16

8. Helper T-cells are activated by

  • Antigen specific signal
  • Co-stimulatory signal
  • Cytokine signal
  • All of these

9. Contents of Drabkin‘s reagent is?

  • Potassium ferricyanide+KCN+KH2PO4+ Non ionic detergent
  • Potassium ferricyanide +KCN+K2HPO4+ Non ionic detergent
  • Potassium ferricyanide+KCN+KH2PO4
  • Potassium ferrocyanide+KCN + KH2PO4

10. Expansion of VCS ? a)Volume conductivity scatteringc)Volume conduction stabilityb)Volume current stabilityd)Volume concentration sediment

  • Volume current scattering
  • Volume conductivity scattering
  • Volume conduction stability
  • Volume conductivity sediment

11. Using the principle of electrical impedance, cells are counted by?

  • measuring conductivity
  • measuring change in electrical resistance
  • measuring viscosity
  • measuring charge

12. Corrected WBC count is calculation from?

  • UncorrectedWBCcount×100No.ofnucleated RBC/100 WBC+100\frac{UncorrectedWBCcount×100}{No.ofnucleated\ RBC/100\ WBC+100}No.ofnucleated RBC/100 WBC+100UncorrectedWBCcount×100​
  • UncorrectedWBCcount+100No.ofnucleated RBC/100 WBC×100\frac{UncorrectedWBCcount+100}{No.ofnucleated\ RBC/100\ WBC\times100}No.ofnucleated RBC/100 WBC×100UncorrectedWBCcount+100​
  • UncorrectedWBCcountNo.ofnucleated RBC/100 WBC\frac{UncorrectedWBCcount}{No.ofnucleated\ RBC/100\ WBC}No.ofnucleated RBC/100 WBCUncorrectedWBCcount​
  • UncorrectedWBCcount×10No.ofnucleated RBC/100 WBC+100\frac{UncorrectedWBCcount×10}{No.ofnucleated\ RBC/100\ WBC+100}No.ofnucleated RBC/100 WBC+100UncorrectedWBCcount×10​

13. Which among the following is NOT a content of Hayem's fluid

  • sodium chloride
  • sodium citrate
  • sodium sulphate
  • mercuric chloride

14. One cubic millimeter is equal to ....

  • 1 micro liter
  • 0.1 micro liter
  • 0.01 micro liter
  • 10 micro liter

15. The needle is used for microtrephine biopsy?

  • Salah
  • kelma
  • jamshidi-swaim
  • jamshid and Salah

16. Anticoagulant used to flush indwelling lines before blood collection ?

  • EDTA
  • heparin
  • potassium oxalate
  • sodium citrate

17. What is the formula for inductive reactance?

  • X L ​ =2πfL
  • X_L=\frac{1}{2\pi fL}
  • X C ​ =2πfC
  • X_C=\frac{1}{2\pi fC}

18. What is the formula for capacitive reactance?

  • X L ​ =2πfL
  • X L ​ = 2πfL 1 ​
  • X C ​ =2πfC
  • X C ​ = 2πfC 1 ​

19.  is the formula for .....

  • Capacitive reactance
  • Inductive reactance
  • A.C. Impedance in a circuit with a higher inductive reactance than capacitive reactance
  • A.C. Impedance in a circuit with a lower inductive reactance than capacitive reactance

20. _________ makes the current lead the voltage

  • Capacitors
  • primarily
  • Both A & B
  • none of the above

21. What is Ehrlich phenomenon?

  • About hypersensitivity reaction
  • About antibody production
  • Toxin-antitoxin interaction
  • None of these

22. Molecular Koch's postulate was formulated by

  • Stanley Falkow
  • Karry B Mullis
  • Ernst Ruska
  • Alexander Fleming

23. Who invented homogenizer

  • Louis Pasteur
  • Rutherford
  • Leeuwenhoek
  • Auguste Gaulin

24. Nucleus is absent in

  • RBC and bacterium
  • RBC and sieve cells
  • RBC only
  • All of these

25. The marker enzyme of cytoplasm is

  • Cathepsin
  • Lactate dehydrogenase
  • Glucose 6 phosphatase
  • ATP synthase

26. Semiautonomous organelle in cell is:

  • Peroxisomes
  • Chloroplast
  • Endoplasmic reticulum
  • Golgi bodies

27. Cell theory was proposed by

  • Beadle and Tatum
  • Robert Hooke
  • Schleiden and Schwann
  • Leeuwenhoek

28. Work on ….….......by Pasteur led to the germ theory of disease?

  • Pasteurization
  • Fermentation
  • Microbes
  • Silkworm disease

29. Father of chemotherapy is

  • Paul Ehrlich
  • Joseph Lister
  • Alexander Fleming
  • Robert Koch

30. Name the Bacteria which do not satisfy Koch's postulate?

  • M.tuberculosis
  • M.leprae
  • Anthrax bacilli
  • Cholera bacilli

31. The scientist who isolated Adenine and thymine

  • Frederich Miescher
  • Altmann
  • Macleod
  • Albrecht Kossel

32. Mrs. Moore made a circuit. It did not light up. Why?

  • The switch is open.
  • The switch is closed.

33. What unit is an inductor measured in?

  • Ohms
  • Henrys
  • Farads
  • Amps

34. What unit is impedance measured in?

  • Ohms
  • Henrys
  • Farads
  • Amps

35. Impedance is the...

  • Resistance created by a capacitor
  • Resistance created by an inductor
  • Resistance created by a combination of resistors, capacitors and inductors
  • Overall current flow

36. In 7 + j6 which part refers to imaginary

  • j6
  • 7
  • Both A & B
  • none of the above

37. Convert to rectangular form:  

  • 49.9+j25.42
  • 49.9

38. Determine in rectangular forms: (3 + j5) + (4 − j3)

  • 7
  • 7-j2
  • 7+j2
  • 7.28∠15.95°

39. Convert:12−j42 to polar form

  • 12-42i
  • 43.68∠−74.06°
  • 43.68∠74.06°
  • 43.68∠74.06°

40. Convert to rectangular form: 

  • -2
  • 2+j3.46
  • 2-j3.46
  • -2-j3.46

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