FREE AND STUDY GAMES ABOUT AC THEORY EXAM

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FREE AND STUDY GAMES ABOUT AC THEORY EXAM

QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -22 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation Question 1: Which of these effects can be reduced using stranded conductors? (skin effect & induction of eddy currents) Why?

Answer:

Skin effect. Stranded provides more surface area than a solid conductor of an equal size, also helps reduce the overall negative effect.Question 2: The average value of halfwave rectified DC is ____ times the peak AC value or one half of the ____ value

Answer:

0.381 full wave rectified Question 3: Prove that the question below is true. E peak = 300 V 20-ohm heater. P= E peak x I peak/2

Answer:

I= 300/20= 15A

P= 300 x 15/2= 2250W

Question 4: When an AC voltage is given, it is always the ____ value unless stated otherwise.

Answer:

effective Question 5: What two factors, not present in a DC circuit, affect the opposition to current flow in an AC circuit?

Answer:

skin effect and induction of eddy currents

Question 6: Can voltage and current be added together?

Answer:

No. You can not add voltage and current together. Vector additions of electrical circuits can only be preformed with like values.Question 7: Does a particular conductor offer the same opposition to current flow in an AC circuit as a DC circuit?

Answer:

No. In a AC circuit you can have skin effect which will increase resistance.Question 8: The effective value of AC voltage will produce the same amount of ____ as a like value of ____ voltage.

Answer:

power DC

Question 9: The average value of a pure sine wave is ____.

Answer:

Question 10: What is the instantaneous value of a 10 amperes peak sine wave at 30°, 45°, and 60°?

Answer:

I inst = 10 x sin (30°) = 5A I inst = 10 x sin (45°) = 7.07A I inst = 10 x sin (60°) = 8.66A

Question 11: Besides a sine wave is there another method to depict the relationship of voltage and current in phase?

Answer:

vectors

Question 12: How can instantaneous current values be determined?

Answer:

I inst= I peak x sin(?)

Question 13: ____ produces heat when current passes through.

Answer:

resistance Question 14: A voltage of 600V peak-to-peak is connected to a 20 ohm heater. What is the wattage?

Answer:

E peak = 600/2= 300V E rms = 300/1.414= 212V

P = 212²/20 = 44944/20 = 2247.2 W

Question 15: Only ____ opposes current flow in a DC circuit.

Answer:

resistance Question 16: What effect would a frequency higher than 60 Hz have on "skin effect"?

Answer:

As the frequency increases, the magnitude of the eddy currents increases. Causing the skin affect to increase Question 17: The average value is the actual average of the ____ voltage or current values across a full cycle.

Answer:

instantaneous

Question 18: What is the instantaneous value at 0° and 180°?

Answer:

Question 19: A pure AC sine wave has an average of ____ volts because the amount above zero is ____ as much as the amount below zero.

Answer:

exactly Question 20: Is resistance the only thing that opposes current flow in an AC circuit?

Answer:

no Question 21: Give your opinion on whether the inductive and capacitive elements in a circuit may be ignored when making resistive circuit calculations for field installations.

Answer:

No. You can't ignore them. They will be used to help you with your calculations.Question 22: Current and voltage in an AC resistive circuit and ____ (in/out of) phase.

Answer:

in