Confused by a exam prep question

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Hello,
My name is Joey Barnett and I am prepping for my exam. I have a test question that I am confused about. I have a different answer than what the instructor has given me. This is based on Article 445.14 The question is:

Live parts of generators operated at MORE than _____ to ground shall not be exposed to accidental contact where accessible to unqualified persons.

1. 50v
2. 120v
3. 150v
4. All the above

The article is identical to the question and states 50v, the instructors answer is all the above. I know that 120v and 150v shall not be exposed but the way the question is worded I believe the answer should be 50v because it states MORE than vs which of the answers below constitute to the NEC.

Thank you for your assistance.
JB
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Well they are all more than 50V but IMO, the instructors answer is incorrect. Sure that each one would be correct if you fill it in but if you answer with the other voltages it would negate the lower ones. By answering with greater than 50V it covers them all
 

mgookin

Senior Member
Location
Fort Myers, FL
I'll add that the question is incorrect.

Many tests are written by "professional test writers" who know nothing about the underlying subject.


Just like mechanized education. It's all trash. You have Pearson and other greedy offshore cartels raping billions of educational dollars every year from this country and the content they produce is absolute garbage. And now the books are being rewritten in garbage to match the online content. It's a real easy sell to the universities because they convince them that the professor can handle more students doing less work, and they're right, but the content is trash. Check this out (Pearson):

Can anyone tell me what this is asking?

Pearson Engineering Computerized Assignment - Copy.jpg
 

RichB

Senior Member
Location
Tacoma, Wa
Occupation
Electrician/Electrical Inspector
Well they are all more than 50V but IMO, the instructors answer is incorrect. Sure that each one would be correct if you fill it in but if you answer with the other voltages it would negate the lower ones. By answering with greater than 50V it covers them all

+1 Bad question
 

mgookin

Senior Member
Location
Fort Myers, FL
Hello,
My name is Joey Barnett and I am prepping for my exam. I have a test question that I am confused about. I have a different answer than what the instructor has given me. This is based on Article 445.14 The question is:

Live parts of generators operated at MORE than _____ to ground shall not be exposed to accidental contact where accessible to unqualified persons.

1. 50v
2. 120v
3. 150v
4. All the above

The article is identical to the question and states 50v, the instructors answer is all the above. I know that 120v and 150v shall not be exposed but the way the question is worded I believe the answer should be 50v because it states MORE than vs which of the answers below constitute to the NEC.

Thank you for your assistance.
JB

Hello Joseph and welcome to the forums! :thumbsup:

Can you tell us who wrote that question?
Was it in a published book?
Or did the instructor just create it after reading an article in the code?

We're having a friendly debate as to whether it's a defective question or not. It would be nice to know the source of the question.

Again, welcome to the forums.

edit: look what I just found:
test q.JPG
Electrician's Exam Prep

By Charles R. Miller

Somebody took a good question and copied it but made up their own answers, possibly. Problem is they inserted bad answers.
 

JFletcher

Senior Member
Location
Williamsburg, VA
That is a trick question imo, and the goal of tests should not be tricks, but rather the subject material. Exceptions to code are one thing, and fine. I'd argue you are also correct tho, since you found the exact code, and 120V and 150V are >50V. Answers A and D are, to me, identical here, and neither is more wrong or right than the other.
 

kwired

Electron manager
Location
NE Nebraska
I have to agree that if the word MORE were to be taken out of the question "that all of the above" would be the correct answer, but because MORE was in the question that the correct answer should be 50 volts.

Instructor may not realize or intend this result, but the wording off the question is incorrect if all of the above was intended to be the answer.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
You all are overthinking it. If the question is verbatim from the code then 50V is the only possible answer. Why over analyze it.
 

Twobnvd

New User
Hello,
My name is Joey Barnett and I am prepping for my exam. I have a test question that I am confused about. I have a different answer than what the instructor has given me. This is based on Article 445.14 The question is:

Live parts of generators operated at MORE than _____ to ground shall not be exposed to accidental contact where accessible to unqualified persons.

1. 50v
2. 120v
3. 150v
4. All the above

The article is identical to the question and states 50v, the instructors answer is all the above. I know that 120v and 150v shall not be exposed but the way the question is worded I believe the answer should be 50v because it states MORE than vs which of the answers below constitute to the NEC.

Thank you for your assistance.
JB
Well if it states 50v than all above would be correct as all the answers are above 50volts. So it's worded to be tricky.... unfortunately

Sent from my SM-N900V using Tapatalk
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Well if it states 50v than all above would be correct as all the answers are above 50volts. So it's worded to be tricky.... unfortunately

Sent from my SM-N900V using Tapatalk


No all the others would be wrong, IMO, because the question states

Live parts of generators operated at MORE than _____ to ground shall not be exposed to accidental contact where accessible to unqualified persons.

Now insert 120V

Live parts of generators operated at MORE than __120V___ to ground shall not be exposed to accidental contact where accessible to unqualified persons.

That statement in itself is true but IMO means that below 120V do not satisfy the sentence.
 

mgookin

Senior Member
Location
Fort Myers, FL
Here's how the question was published:

Live parts of generators operated at more than __________ to ground shall not be exposed to accidental contact where accessible to unqualified persons.
a) 50 volts
b) 65 volts
c) 150 volts
d) 250 volts

And the answer, of course, is a) 50 volts.

The book is "Electricians Exam Prep" by Charles R. Miller.

The problem came when someone took it from the book and changed the answers. Whoever did that, and made d) read "all of the above" should not be an instructor.

A test question should never trip up the student. It should be crystal clear, to the point, and without any ambiguity.

Joey: You passed the test. Your instructor failed!
 
Sorry for the late response

Sorry for the late response

Hello,

Thank you for all of yalls feed back. I forgot my password and got busy with the Christmas Holidays. To answer the questions about where the question came from, it came from Ray Holders exam prep book. I have not seen the question but according to Ray Holder all the questions came from one of the exams, and on the test and NO, I did not pass. I took it twice, missed it by 7 questions and 1 question. I also wanted to let yall know I am taking the Texas exam, not sure how relevant that is.

I believe someone stated that the test is written not to confuse you, I have to disagree. The reason I say this is because while taking my exam some of the questions I noticed did not use ex: over 100 volts or 100 volts or less, it would state per word what the NEC had but would change the 100v too 120v or 85v. Yes, I know it should be understood that 120v is over 100v but it also tells me that they are manipulating the question from the NEC to throw you off. This one is an easy one, the ones that get me are when a single word is changed or they are looking for you to add a percentage to the answer while giving you to the answer with and without it.

I am an industrial electrician and a lot of the stuff I have never had to deal with so it probably seems more difficult to me than it may to others. I wish I would have taken it when I first got out of school. lol

Again, thank you for everyone's help. Any pointers on taking the exam are greatly appreciated.

Joey
 

Martin B

Member
Location
Nebraska
Hello Joey,

I just passed my contractors, which means I studied for these types of exams more the once if you catch my drift. My advice is to not get hug up on getting a Q or two wrong on your home work. I think the point is to practice looking stuff up in the code book fast, and it definitely seems you know where to fined the answer to this Q in the code book.

The "Code" questions and answers in your exam will probably be word for word out the NEC. Make sure you can fined exactly (including Exceptions) the paragraph your test question in referring to in two or three minutes.

Good luck,
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
Can anyone tell me what this is asking?

View attachment 13980
Yes. It is a basic physics question, though there are some words missing in the first line (somewhere between "shown" and "wheel"). Thus, I would not be able to work the problem and give them an answer. What you are looking at is a pulley with a cord wrapped around it and with a weight suspended below. You have a brake that keeps this thing from moving. Then you release the brake and wait 2 seconds. You are being asked how fast it will be spinning at that moment.

 

Carultch

Senior Member
Location
Massachusetts
I'll add that the question is incorrect.

Many tests are written by "professional test writers" who know nothing about the underlying subject.


Just like mechanized education. It's all trash. You have Pearson and other greedy offshore cartels raping billions of educational dollars every year from this country and the content they produce is absolute garbage. And now the books are being rewritten in garbage to match the online content. It's a real easy sell to the universities because they convince them that the professor can handle more students doing less work, and they're right, but the content is trash. Check this out (Pearson):

Can anyone tell me what this is asking?

View attachment 13980


Yes I can tell you what that question is asking. The first sentence doesn't make grammatical sense, but I can gather enough information to solve what they are intending to ask. They are also giving you a red herring in the first sentence, since you do not need to know the weight of the wheel.

Here is a similar problem, and its solution:
https://www.youtube.com/watch?v=-K-JuucvQiE

The one thing I'm not getting in your specific example, is what to do with the "double pulley" information. And it very well could be another red herring. Is it two pulleys rigidly connected on the same axle (my assumption)? Or are they connected in some other way? And is the moment of inertia the value given for a single pulley (thus we'd need to multiply by two, my assumption), or for the combination?
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
You do need to know the weight of the wheel because from that you can calculate the mass. Then from that and an assumption of uniform mass distribution in each (equal thickness) pulley you can get the moment of rotational inertia.
 

Carultch

Senior Member
Location
Massachusetts
You do need to know the weight of the wheel because from that you can calculate the mass. Then from that and an assumption of uniform mass distribution in each (equal thickness) pulley you can get the moment of rotational inertia.

They give you the moment of inertia directly in that problem. Mass and geometry assumptions, while interesting, are not needed.

Unless they intended to give you moment of inertia of pulley A, and make you calculate that for pulley B, and thus add them up accordingly.
 

Smart $

Esteemed Member
Location
Ohio
They give you the moment of inertia directly in that problem. Mass and geometry assumptions, while interesting, are not needed.

Unless they intended to give you moment of inertia of pulley A, and make you calculate that for pulley B, and thus add them up accordingly.
I suspect mgookin was aware of the question's idiosyncrasies when he posted it. Rationale precludes only the author or those with an answer key can arrive at the desired answer without guesswork or assumption.
 

RichB

Senior Member
Location
Tacoma, Wa
Occupation
Electrician/Electrical Inspector
Not really a bad question. The teachers answer is bad. The question is verbatim from the NEC

After looking at some more of the responses and thinking over what you stated Dennis--

The question is a good as it is straight from the NEC

The answers are somewhat confusing especially for a new guy not familiar with how to or not to interpret the Code

Instead of multiple choice it probably should have been fill in the blank

These tests should not be confusing but should challange the taker, make them think

A little disinformation, read extra or superfolous is ok, but not like this question where each answer individuaqlly is "technically(spelling???)" correct but when taken as a group only A is acceptable
 
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