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Multiple choice question for engineering

Set 1

1. Absorption meter is __________ and ____________ of the chemical state of the element concerned.
a) Non-destructive, independent
b) Destructive, independent
c) Non-destructive, dependent
d) Destructive, dependent

View Answer

Answer: a [Reason:] Absorption meters give information about the absorbing material. It is non-destructive and independent of the chemical state of the element concerned.

2. X-ray absorption meters have which of the following major disadvantages?
a) Low accuracy
b) Low range
c) Low sensitivity
d) It is destructive

View Answer

Answer: c [Reason:] Absorption meters give information about the absorbing material. X-ray absorption meters have low sensitivity.

3. The applications of X-ray absorption meters are limited when compared with X-ray emission procedures.
a) True
b) False

View Answer

Answer: a [Reason:] The applications of X-ray absorption meters are limited when compared with X-ray emission procedures. They are also limited when compared with fluorescence procedures.

4. In absorption meter, which of the following is placed between the cell and the X-ray tube?
a) Collimator
b) Filter
c) Chopper
d) Attenuator

View Answer

Answer: c [Reason:] In Absorption meter, chopper is placed between the cell and the X-ray tube. It interrupts the half of the X-ray beam.

5. In absorption meter, which of the following is placed between the chopper and the reference cell?
a) Collimator
b) Filter
c) Photomultiplier tube
d) Attenuator

View Answer

Answer: d [Reason:] In absorption meter, attenuator is placed between the chopper and the reference cell. A variable thickness aluminium attenuator is used.

6. In absorption meter, the two halves of the X-ray beam are allowed to fall on which of the following components?
a) Collimator
b) Filter
c) Photomultiplier tube
d) Attenuator

View Answer

Answer: c [Reason:] In absorption meter, the two halves of the X-ray beam are allowed to fall on the photomultiplier tube. One beam passes through the sample and the other beam passes through the reference.

7. The photomultiplier tube used is absorption meter is coated with which of the following materials?
a) Sodium
b) Potassium
c) Phosphorous
d) Chlorine

View Answer

Answer: c [Reason:] The photomultiplier tube used is absorption meter is coated with phosphorous. Only one photomultiplier tube is commonly present for both the beams.

8. In absorption meter, which of the following is adjusted until the absorption of two X-ray beams are brought into balance?
a) Collimator
b) Filter
c) Photomultiplier tube
d) Attenuator

View Answer

Answer: d [Reason:] In absorption meter, the attenuator is adjusted until the absorption of two X-ray beams are brought into balance. A variable thickness aluminium attenuator is used.

9. In absorption meter, the change in thickness of aluminium required for different samples is a function of the difference in which of the following parameters?
a) Amount
b) Concentration
c) Colour
d) Composition

View Answer

Answer: d [Reason:] In absorption meter, the change in thickness of aluminium required for different samples is a function of the difference in composition. A variable thickness attenuator used allows this function.

10. Absorption meters cannot be used to detect broken bones.
a) True
b) False

View Answer

Answer: b [Reason:] Absorption meters can be used to detect broken bones. It can also be used to locate trace elements.

Set 2

1. Electron spin resonance involves detecting the detection of a physical phenomenon of _________ of electromagnetic radiation.
a) Adsorption
b) Absorption
c) Radiation
d) Reflection

View Answer

Answer: a [Reason:] Electron spin resonance uses the detection of a physical phenomenon of absorption of electromagnetic radiation. Paramagnetic species absorb EM radiation.

2. Electron spin resonance is also known as which of the following?
a) Electron paramagnetic resonance
b) Electron diamagnetic resonance
c) Electron paramagnetic reoccurrence
d) Electron diamagnetic reoccurrence

View Answer

Answer: a [Reason:] Electron spin resonance is also known as electron paramagnetic resonance. It is a valuable research analysis tool.

3. The value of magnetic moment is known as which of the following?
a) Thompson magneton
b) Bohr magneton
c) Goldstein magneton
d) Rutherford magneton

View Answer

Answer: b [Reason:] Electron spin resonance is based on the spin associated with the electron. There is a magnetic moment the value of which is known as Bohr magneton.

4. When a strong magnetic field is applied to the unpaired spins of an electron, the electrons will be split into two groups.
a) True
b) False

View Answer

Answer: a [Reason:] When a strong magnetic field is applied to the unpaired spins of an electron, the electrons will be split into two groups. Electron spin resonance is based on the spin associated with the electron.

5. When the electrons are aligned either parallel or antiparallel to the direction of external magnetic field, the electrons will precess about the axis at a frequency that is proportional to which of the following?
a) Applied magnetic field
b) Electron magnetic moment
c) Applied magnetic field and electron magnetic moment
d) Neither applied magnetic field not electron magnetic moment

View Answer

Answer: c [Reason:] When the electrons are aligned either parallel or antiparallel to the direction of external magnetic field, the electrons will start to precess about the axis at a frequency that is proportional to both applied magnetic field and electron magnetic moment.

6. If a weaker radiofrequency alternating magnetic field, having the frequency of precession of the electron is applied at right angles to fixed magnetic field, which of the following occurs?
a) Fragmentation
b) Scattering
c) Resonance
d) Absorption

View Answer

Answer: c [Reason:] Resonance occurs when a weaker radiofrequency alternating magnetic field with the frequency of precession of the electron is applied at right angles to fixed magnetic field.

7. If the population of ground state exceeds the population of the excited state a net absorption of __________ radiation takes place.
a) Infrared
b) Ultraviolet
c) Microwave
d) X-ray

View Answer

Answer: c [Reason:] If the population of ground state exceeds the population of the excited state a net absorption of microwave radiation takes place. The signal would be proportional to the population difference.

8. The population ratio can be given by which of the following laws?
a) Bohr law
b) Beer-Lambert law
c) Kelvin law
d) Boltzmann law

View Answer

Answer: d [Reason:] The population ratio can be given by Boltzmann law. ‘k’ is the Boltzmann constant.

9. The sensitivity of measurement is greatly enhanced by using which of the following?
a) High magnetic field
b) Low magnetic field
c) High electric field
d) Low electric field

View Answer

Answer: a [Reason:] The sensitivity of measurement is greatly enhanced by using high magnetic field. Low magnetic field reduces sensitivity.

10. ESR sensitivity increases with __________ temperature and with _________ magnetic field strength.
a) Increasing, increasing
b) Increasing, decreasing
c) Decreasing, increasing
d) Decreasing, decreasing

View Answer

Answer: c [Reason:] ESR sensitivity increases with decreasing temperature and with increasing magnetic field strength. ESR sensitivity means net absorption.

11. ESR is remarkably sensitive when compared with NMR.
a) True
b) False

View Answer

Answer: a [Reason:] ESR is remarkably sensitive when compared with NMR. NMR stands for Nuclear Magnetic Resonance spectroscopy.

12. Reflex klystron is used in which of the following frequency ranges?
a) 1000 to 2000 MHz
b) 1000 to 10000 MHz
c) 1000 to 15000 MHz
d) 1000 to 20000 MHz

View Answer

Answer: d [Reason:] Reflex klystron is used in the frequency range of 1000 to 20000 MHz. It is a low power device.

13. Under ideal conditions, a commercial X-band spectrometer can detect of the order of which of the following number of spins at room temperature?
a) 101
b) 105
c) 1010
d) 1012

View Answer

Answer: d [Reason:] Under ideal conditions, a X-band spectrometer is capable of detecting of the order of 1012 spins at room temperature. ESR is very sensitive.

14. Waveguides look like _________ cross-section pipes with dimensions of the order of the wavelength to be transmitted.
a) Triangular
b) Circular
c) Rectangular
d) Square

View Answer

Answer: c [Reason:] Waveguides look like rectangular cross-section pipes with dimensions of the order of the wavelength to be transmitted. Waveguides cannot be too small or too large.

15. Klystron can generate power in which of the following ranges?
a) 10 – 100 mW
b) 10 – 200 mW
c) 10 – 500 mW
d) 100 – 400 mW

View Answer

Answer: c [Reason:] Klystron can generate power in the range of 10-500 mW. It is a low power device.

Set 3

1. Which of the following is called Bar-Hillel lemma?
a) Pumping lemma for regular language
b) Pumping lemma for context free languages
c) Pumping lemma for context sensitive languages
d) None of the mentioned

View Answer

Answer: b [Reason:] In automata theory, the pumping lemma for context free languages, also kmown as the Bar-Hillel lemma, represents a property of all context free languages.

2. Which of the expressions correctly is an requirement of the pumping lemma for the context free languages?
a) uvnwxny
b) uvnwnxny
c) uv2nwx2ny
d) All of the mentioned

View Answer

Answer: b [Reason:] Let L be a CFL. Then there is an integer n so that for any u that belong to language L satisfying |t| >=n, there are strings u, v, w, x, y and z satisfying t=uvwxy |vx|>0 |vwx|<=n For any m>=0, uvnwxny ∈ L

3.Let L be a CFL. Then there is an integer n so that for any u that belong to language L satisfying
|t|>=n, there are strings u, v, w, x, y and z satisfying
t=uvwxy.
Let p be the number of variables in CNF form of the context free grammar. The value of n in terms of p :
a) 2p
b) 2p
c) 2p+1
d) p2

View Answer

Answer: c [Reason:] This inequation has been derived from derivation tree for t which must have height at least p+2(It has more than 2p leaf nodes, and therefore its height is >p+1).

4. Which of the following gives a positive result to the pumping lemma restrictions and requirements?
a) {aibici|i>=0}
b) {0i1i|i>=0}
c) {ss|s∈{a,b}*}
d) None of the mentioned

View Answer

Answer: b [Reason:] A positive result to the pumping lemma shows that the language is a CFL and ist contradiction or negative result shows that the given language is not a Context Free language.

5. Using pumping lemma, which of the following cannot be proved as ‘not a CFL’?
a) {aibici|i>=0}
b) {ss|s∈{a,b}*}
c) The set legal C programs
d) None of the mentioned

View Answer

Answer: d [Reason:] There are few rules in C that are context dependent. For example, declaration of a variable before it can be used.

6. State true or false:
Statement: We cannot use Ogden’s lemma when pumping lemma fails.
a) true
b) false

View Answer

Answer: b [Reason:] Although the pumping lemma provides some information about v and x that are pumped, it says little about the location of these substrings in the string t. It can be used whenever the pumping lemma fails. Example: {apbqcrds|p=0 or q=r=s}, etc.

7. Which of the following cannot be filled in the blank below?
Statement: There are CFLs L1 nad L2 so that ___________is not a CFL.
a) L1∩L2
b) L1′
c) L1*
d) None of the mentioned

View Answer

Answer: c [Reason:] A set of context free language is closed under the following operations: a) Union b) Concatenation c) Kleene

8. The pumping lemma is often used to prove that a language is:
a) Context free
b) Not context free
c) Regular
d) None of the mentioned

View Answer

Answer: b [Reason:] The pumping lemma is often used to prove that a given language L is non-context-free, by showing that arbitrarily long strings s are in L that cannot be “pumped” without producing strings outside L.

9. What is the pumping length of string of length x?
a) x+1
b) x
c) x-1
d) x2

View Answer

Answer: a [Reason:] There exists a property of all strings in the language that are of length p, where p is the constant-called the pumping length .For a finite language L, p is equal to the maximum string length in L plus 1.

10. Which of the following does not obey pumping lemma for context free languages ?
a) Finite languages
b) Context free languages
c) Unrestricted languages
d) None of the mentioned

View Answer

Answer: c [Reason:] Finite languages (which are regular hence context free ) obey pumping lemma where as unrestricted languages like recursive languages do not obey pumping lemma for context free languages.

Set 4

1. A push down automaton employs ________ data structure.
a) Queue
b) Linked List
c) Hash Table
d) Stack

View Answer

Answer: d [Reason:] A push down automata uses a stack to carry out its operations. They are more capable than the finite automatons but less than the turing model.

2. State true or false:
Statement: The operations of PDA never work on elements, other than the top.
a) true
b) false

View Answer

Answer: a [Reason:] The term pushdown refers to the fact that the elements are pushed down in the stack and as per the LIFO principle, the operation is always performed on the top element of the stack.

3. Which of the following allows stacked values to be sub-stacks rather than just finite symbols?
a) Push Down Automaton
b) Turing Machine
c) Nested Stack Automaton
d) None of the mentioned

View Answer

Answer: c [Reason:] In computational theory, a nested stack automaton is a finite automaton which makes use of stack containing data which can be additional stacks.

4. A non deterministic two way, nested stack automaton has n-tuple definition. State the value of n.
a) 5
b) 8
c) 4
d) 10

View Answer

Answer: d [Reason:] The 10-tuple can be stated as: NSA= ‹Q,Σ,Γ,δ,q0,Z0,F,[,],]›.

5. Push down automata accepts _________ languages.
a) Type 3
b) Type 2
c) Type 1
d) Type 0

View Answer

Answer: b [Reason:] Push down automata is for Context free languages and they are termed as Type 2 languages according to Chomsky hierarchy.

6. The class of languages not accepted by non deterministic, nonerasing stack automata is _______
a) NSPACE(n2)
b) NL
c) CSL
d) All of the mentioned

View Answer

Answer: d [Reason:] NSPACE or non deterministic space is the computational resource describing the memory space for a non deterministic turing machine.

7. A push down automaton with only symbol allowed on the stack along with fixed symbol.
a) Embedded PDA
b) Nested Stack automata
c) DPDA
d) Counter Automaton

View Answer

Answer: d [Reason:] This class of automata can recognize a set of context free languages like {anbn|n belongs to N}

8. Which of the operations are eligible in PDA?
a) Push
b) Delete
c) Insert
d) Pop

View Answer

Answer: a, d [Reason:] Push and pop are the operations we perform to operate a stack. A stack follows the LIFO principle, which states its rule as: Last In First Out.

9. A string is accepted by a PDA when
a) Stack is empty
b) Acceptance state
c) Both (a) and (b)
d) None of the mentioned

View Answer

Answer: c [Reason:] When we reach the acceptance state and find the stack to be empty, we say, the string has been accepted by the push down automata.

10. The following move of a PDA is on the basis of:
a) Present state
b) Input Symbol
c) Both (a) and (b)
d) None of the mentioned

View Answer

Answer: c [Reason:] The next operation is performed by PDA considering three factors: present state,symbol on the top of the stack and the input symbol.

Set 5

1. If L1, L2 are regular and op(L1, L2) is also regular, then L1 and L2 are said to be ____________ under an operation op.
a) open
b) closed
c) decidable
d) none of the mentioned

View Answer

Answer: b [Reason:] If two regular languages are closed under an operation op, then the resultant of the languages over an operation op will also be regular.

2. Suppose a regular language L is closed under the operation halving, then the result would be:
a) 1/4 L will be regular
b) 1/2 L will be regular
c) 1/8 L will be regular
d) Al of the mentioned

View Answer

Answer: d [Reason:] At first stage 1/2 L will be regular and subsequently, all the options will be regular.

3. If L1′ and L2′ are regular languages, then L1.L2 will be
a) regular
b) non regular
c) may be regular
d) none of the mentioned

View Answer

Answer: a [Reason:] Regular language is closed under complement operation. Thus, if L1′ and L2′ are regular so are L1 and L2. And if L1 and L2 are regular so is L1.L2.

4. If L1 and L2′ are regular languages, L1 ∩ (L2′ U L1′)’ will be
a) regular
b) non regular
c) may be regular
d) none of the mentioned

View Answer

Answer: a [Reason:] If L1 is regular, so is L1′ and if L1′ and L2′ are regular so is L1′ U L2′. Further, regular languages are also closed under intersection operation.

5. If A and B are regular languages, !(A’ U B’) is:
a) regular
b) non regular
c) may be regular
d) none of the mentioned

View Answer

Answer: a [Reason:] If A and B are regular languages, then A Ç B is a regular language and A ∩ B is equivalent to !(A’ U B’).

6. Which among the following are the boolean operations that under which regular languages are closed?
a) Union
b) Intersection
c) Complement
d) All of the mentioned

View Answer

Answer: d [Reason:] Regular languages are closed under the following operations: a) Regular expression operations b) Boolean operations c) Homomorphism d) Inverse Homomorphism

7. Suppose a language L1 has 2 states and L2 has 2 states. After using the cross product construction method, we have a machine M that accepts L1 ∩ L2. The total number of states in M:
a) 6
b) 4
c) 2
d) 8

View Answer

Answer: 4 [Reason:] M is defined as: (Q, S, d, q0, F) where Q=Q1*Q2 and F=F1*F2

8. If L is a regular language, then (L’)’ U L will be :
a) L
b) L’
c) f
d) none of the mentioned

View Answer

Answer: a [Reason:] (L’)’ is equivalent to L and L U L is subsequently equivalent to L.

9. If L is a regular language, then (((L’)r)’)* is:
a) regular
b) non regular
c) may be regular
d) none of the mentioned

View Answer

Answer: a [Reason:] If L is regular so is its complement, if L’ is regular so is its reverse, if (L’)r is regular so is its Kleene.

10. Which among the following is the closure property of a regular language?
a) Emptiness
b) Universality
c) Membership
d) None of the mentioned

View Answer

Answer: d [Reason:] All the following mentioned are decidability properties of a regular language. The closure properties of a regular language include union, concatenation, intersection, Kleene, complement , reverse and many more operations.