Process Engineering Interview Questions | Glassdoor

# Process Engineering Interview Questions

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Process engineering interview questions shared by candidates

## Top Interview Questions

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### Continuous Improvement Process Engineer at PNC Financial Services Group was asked...

Apr 10, 2014
 Explain a situation where you had to navigate a difficult political landscape. 3 AnswersI explained some issues on my current project.I described my situation when I first entered my last job. The established members of my team weren't very receptive to new authority but I was able to show them the respect and support that they needed in order to gain their trust and make a great work environment.Stick to the FACTS.

### Financial Software Developer at Bloomberg L.P. was asked...

Oct 1, 2010
 An array of 99 elements contains integers from 1 to 100 with one missing element. Find the missing element.22 Answers1001. calculate the sum of elements in array say SUM 2. sum of numbers 1 to 100 is(n* (n+1))/2 = 5050 when n==100 3. missing element is (5050-SUM)100Show More ResponsesThe parameters of the question do not allow you to determine what element is missing. Either more information should be supplied, or all answers are equally correct.How could an array size of 99 elements contain 1 - 100? Should either be integers 1-99 or 2-100 , in either case there is no missing element. All indices are accounted for.Sum them and then subtract them from 5050. In general, if an array of size n - 1 elements has unique elements from 1 to n, then the missing element can be found by subtracting the sum of the elements in the array from sum(1 ... n) = n * (n + 1) / 2. Alternately, one could use a boolean array of length n with all values set to false and then for each value, set array[val - 1] to true. To find the missing value, scan through the array and find the index which is set to false. Return index + 1. This requires O(n) memory and two passes over an O(n) array (instead of constant memory and one pass), but has the advantage of actually allowing you to verify whether or not the input was well formed.Admittedly, this question is poorly posed; however, the answer they are looking for refers to the syntax/nomenclature of some (not all) programming languages to index arrays starting at “0.” As such the 1-100 stored values would be in entries 0-99 of the array.Read the question. Here are the steps to solve it: 1) find the sum of integers 1 to 100 2) subtract the sum of the 99 members of your set 3) the result is your missing element! Very satisfying!Sort array. While loop with an index variable with condition of next element being 1 greater than previous element. When loop breaks, return the value of the index.Doing the expected sum and subtracting the actual gives the run time of O(2n), however a bucket sort will almost always do it in less time (somewhere between O(n) and O(2n)): 1. create a 101-int (or boolean) array (to have a 100-index) 2. traverse original and for each int, assign value in bucket array to 1 or true. 3.After first traversal, traverse created array starting at one, and when value is false, print it.100100 coz in array it initial value starts frm 0 to 100. or else 4 further clarification u can study array chapter in c or c++100Show More ResponsesThe question: "An array of 99 elements contains integers from 1 to 100 with one missing element. Find the missing element." The information states that the integer count is 1 to 100. I take this to be inclusive of all elements in the array so that the missing inters would be subjective to their arrangement or random. In other words, I do not have enough information to say which one.1I need more information. 1. Are the integers unique in this array? 2. Do I have enough information to find the sum of the integers in the array (or some aggregation)? If sum is available, then, the answer is 5050-sum{integers}.Bucket Sort works and summation works. I think both are good, practical and clever solutions. I think sorting the array then searching may be unnecessary computation. Another interesting method which may be faster. SIMD computers may do this particularly quickly: Do a bitwise operation on all the elements: Result = Array[0] xor Array[1] xor ... Array[98] xor 1 xor 2 xor ... xor 100 Result = Missing number. Explanation: When you xor 2 identical numbers your result = 0. For example, 5 xor 5 -> 101 xor 101 = 000. (5 in decimal is 101 in binary). Knowing that "xoring" 2 identical numbers results in zero is useful. Now we apply this useful info to the problem. Array is Identical to a list of 1,2,3,...,100 except for one number. In other words 1,2,3,...,100 duplicates all of array's elements and adds one extra element that is missing in Array. Therefore, we now have 2 instances of each element in the Array in addition to one extra element in 1,2,3,...,100. We can see when you xor two duplicate numbers you get zero. Because we have pairs for all numbers in Array and one extra number we are essentially "xoring" the missing number with zero. When we xor the missing number with zero we get the missing number. (For example, 6 xor 0 -> 110 xor 000 = 110)The question states that one (not two or three or n) element ("value") from 1 to 100 is missing. There are 99 elements ("values") in the array. The question implies that the data is well-formed because it states that only element is missing. It doesn't ask you to find the missing value(s), but the one (singular) missing element. With the problem constrained, the solution falls out. Subtracting from 5050 is an elegant solution, but not obvious as to why it works. The array of booleans is more obvious, but doesn't scale well.I agree with one of the answers in this thread...5050-sum(elements) = missing item. Other approach that crossed my mind is something similar to binary search. Check the index of 50th element: if A(50) == 50, the missing element > 50, else if A(50) > 50, missing element <50. Do this iteratively. The number of comparisons would be log 100 = 7.0100Add 1-100 to a hash of 100 elements. Then compare each element with the hash.. Answer in o(n)

### Process Engineer at Intel Corporation was asked...

Oct 9, 2013
 A batch of wafers are getting cleaned in acid, aqueous and drying environments and a technician calls you in the middle of the night reporting that the wafers are having an unusual number of defects. How do solve the problem and what advice do you give the technician?3 AnswersBreak up the problem as much as possible to narrow down the solution. If you are on the right track, they will help you with the solution.My advice to the technician would be to clean the wafers with acetone, ipa and di water after the acid cleaning, as acid cleaning removes the inorganic impurities but not the organic impurities, acetone, ipa and di water will remove the organic impurities and hopefully the defects will be reducedMy advice to the technician would be to clean the wafers with acetone, ipa and di water after the acid cleaning, as acid cleaning removes the inorganic impurities but not the organic impurities, acetone, ipa and di water will remove the organic impurities and hopefully the defects will be reduced

### Process Engineer at Intel Corporation was asked...

Sep 8, 2011
 Do you have any questions for me?3 AnswersTry to prepare a lot of questions for them.I also interviewed but haven't heard for 4 weeks. I hear they are in a hiring freeze. As long as you don't have rejection that should be okay. What group did you interview with?To the OP. Call them and ask about your status! Call the engineer who flew you out. From my experience if you don't prod them a bit you might not get the offer.

### Process Engineer Intern at BP was asked...

Sep 13, 2009
 You are in charge of building a pipeline 200 miles from the ocean to a refinery and there is a mountain range in the way. What issues are involved in this project?3 Answersmostly the mountainsHydrate formation Slugging and pressure lossPressure loss in the piping, the pumps may need a huge head / energy requirement to push the chemicals through. The different altitudes create a change in the chemical composition, increase vapor pressure which need to be compensated for before being pumped or reacted

### Process Development Engineer at Cree was asked...

Oct 30, 2011
 Can Si be used to make LEDs ?3 AnswersSi can be used as a substrate in LEDs, but it cannot be used in the p-n junction because the bandgap energy is too small to produce visible light.Technically: Yes. But it has an indirect bandgap, so you really wouldn't want to.The energy bandgap of Si at room temperature is 1.12eV. Since the relationship between photon energy and wavelength is E(eV)=1.24/wavelength(micrometers), one can calculate that Si could emit a ligth in infrared optical spectrum: wavelength=1.24/1.12eV=1.11 micrometers. BUT, Si is indirect semiconductor! And therefore does not emit significant amounts of light due to the requirement of momentum conservation in optical transitions.

### Process Engineer at Cree was asked...

Dec 4, 2013
 If you're stuck in the middle of nowhere with a broken down car, how can you determine what the problem is?3 AnswersIt seems you have no gas.but when you encountered an engine trouble you cannot easily determine the problem without knowledge of it.objective: For example: diagnose & fix the car; or get out of nowhere; be at peace with being nowhere.Hmmmm, "If you're stuck in the middle of nowhere with a broken down car, how can you determine what the problem is?" A. The problem is obvious :0 You're stuck in the middle of nowhere and your car is broken down! Hopefully you have a cell phone with a cell tower nearby.

### Process Engineer at Cree was asked...

Dec 4, 2013
 If an ice cube melts in water, does the water level rise or fall? Explain with details.3 AnswersNo, the water neither rises nor falls. The buoyancy of the ice does not affect the water level, it will raise the water level if you add ice to an already full glass of water, however because ice is lighter than the water (which is the oddity of water as an element versus other elements on the periodic table), the level stays the same.no, although the ice melts in a certain container if it is floating on a water the volume of ice is already condense on the water itself so water level will never changeno, the water level will remain the same because the displacement of the ice cube is what determines water level,not the volume of the portion of the ice cube that is submerged.

### Senior Process Engineer at Intel Corporation was asked...

Nov 11, 2010
 What is the net charge of a plasma?2 Answers0 at center of plasma. No of electrons equal no ions. Positive on the sheath.I think electrons are lost when the come in contact with chamber walls or electrodes and finally number of ions is more than electrons. So, plasma is positively charged between electrodes except near the electrode regions

### Senior Process Engineer at Intel Corporation was asked...

Nov 11, 2010
 At what rotational speed do turbopumps operate?2 Answers480Hzas for as I know its around ~30,000rpm. Correct me if I am wrong.
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