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Right choice is (a) True

Explanation: The above statement is true. The magnaflux method ALSO DETECTS the location of flaws. This is because the powder on the specimen is disturbed as magnetic LINES of force are also disturbed in the location of the flaws.

The correct CHOICE is (b) RADIOGRAPHY

Easiest explanation: Non-destructive testing way of materials refers to a process of inspection where the material is not DESTROYED or HARMED in any way. Radiography is a non-destructive way of inspecting materials.

The correct OPTION is (b) False

The best I can explain: Extensometer is an instrument used to measure the change in the length of a material. It should not be PLACED ANYWHERE to the SPECIMEN. It should be FIXED at the gage marks of the specimen being tested in the testing machine.

The CORRECT answer is (c) proportional limit

For explanation: Proof stress of a material can also be called a proportional limit. The PROCEDURE to FIND the ELASTIC limit and proof stress are similar, but the quantities are different. Yield limit can be found through tension testing, but it is not the same as proof stress.

Correct choice is (d) 8 KG per SQUARE millimeter

To elaborate: Brinell hardness number = \(\frac{Load \,APPLIED}{AREA \,of \,impression \,(spherical)}\)

= \(\frac{2000}{250}\)

= 8 kg per square millimeter.

The correct answer is (b) energy

To elaborate: The Charpy test, like an Izod test, gives the energy ABSORBED by the specimen/MATERIAL being tested. This is used to obtain the comparative PROPERTIES of the desired MATERIALS. It also TELLS if the material is extremely brittle.

Correct OPTION is (b) 500,000,000

To elaborate: A HUGE number of test CYCLES are REQUIRED to determine the fatigue strength of a material. The number of cycles required for aluminium alloys is 500,000,000. It is the same for MAGNESIUM alloys as well.

Right choice is (a) steel, diamond

To explain: ROCKWELL hardness value is found by calculating the penetration of either a steel ball or diamond cone under a particular LOAD. The Rockwell hardness NUMBER appears on the dial of the machine.

Correct choice is (d) demagnetized

Explanation: Some Aircraft MATERIALS TYPICALLY undergo the magnaflux INSPECTION process. After the inspection process is done the PARTS have to be demagnetized before being used for manufacturing. This is because otherwise, they will interfere with the plane’s compass.

The correct choice is (b) False

To explain I would SAY: There is typically no such particular requirement that the specimen of the BENDING test must be taken only PARALLEL to the grain. It is often REQUIRED for the specimen to be taken in both parallel and across the grain.

The CORRECT answer is (c) TWISTING

For explanation: Torsion is defined as the twisting of a specimen caused by a CERTAIN AMOUNT of torque. COMPRESSIVE forces are forces that are applied to an object that results in the specimen getting compacted.

Right option is (c) 30

To elaborate: The length required for a specimen of DIAMETER less than 0.033 inches in the torsion test is 30 inches. The length required for the wire being used in this experiment DEPENDS on the diameter of the specimen.

The correct choice is (c) 8

To explain I would say: Gammagraphs of steel PARTS or materials as THICK as eight inches can also be acquired. This is higher COMPARED to RADIOGRAPHS with X-rays that can be used for steel as thick as only three inches.

The correct option is (a) Fixing a specimen in the machine to be broken by WEIGHT or heavy pendulum

Best EXPLANATION: An impact test is a procedure that INVOLVES notching a specimen on one side and FASTENING it to a machine to be broken, either by a SWINGING pendulum that is heavy or by a falling weight on it.

The correct option is (b) False

The best I can EXPLAIN: This statement is not true. In the torsion TEST, steps are taken to ensure that kinking does not occur. The specimen is SUBJECTED to the required amount of tension so that kinking does not occur to affect the experiment.

Correct CHOICE is (b) False

The explanation: The statement is incorrect. Hardness testing machines don not GIVE the exact same results. Even if they are similar in TYPE, obtaining exact same results EVERY time is not possible.

Right option is (a) True

The EXPLANATION is: A LOT of basic PROPERTIES of a material can be obtained through TENSION testing. It is an important test. ONE such property is the elongation of a material. It refers to the amount of increase in the length of a material.

The correct CHOICE is (b) Black IRON OXIDE

To ELABORATE: It is necessary to put a substance on the specimen that can indicate the PRESENCE of flaws on it. Black iron oxide or ferroso ferric oxide is generally used as magnetic powder. They can be applied either wet or dry.

The correct choice is (c) All directions

To explain I would say: It is important in the MAGNAFLUX INSPECTION method that the LINES of force (magnetic) GO through the defect perpendicularly. For this reason, since the location of defects is not know, it should be induced in all directions.

Correct option is (b) Magnaflux

The BEST I can explain: The inspection METHOD is performed on MAGNETIC objects and used to determine cracks, LAPS, etc. On the material or part being inspected is called as magnaflux. Bending and fatigue are not inspection METHODS.

The correct answer is (C) Radiography and magnaflux INSPECTION

Explanation: It is materials being used in aircraft construction that should not experience failure while usage. HENCE, it is crucial for the materials to UNDERGO inspection to detect any cracks or defects. There are TWO standard inspection methods, they are radiography and magnaflux inspection.

Right answer is (b) False

To explain I would SAY: The statement is not true. It is not at all easy to determine the fatigue stress of a MATERIAL. In fact, it is so difficult and consuming that there are lots of materials whose fatigue strength has not been FOUND.

The correct option is (a) across

To EXPLAIN I would SAY: In the case of shop bending, it is usually preferred that all the bends be made across the grain. Once the test SPECIMEN passes the bending test, it is assured that the material is of good quality and there is a DIMINISHED possibility of CRACKING.

The correct choice is (b) To OBTAIN accuracy

To explain: An EXTENSOMETER must be used in reading the permanent set. An accurate extensometer is REQUIRED to obtain the change in the property after the experiment is DONE, without any mistakes or problems with accuracy.

The correct option is (a) True

Explanation: There is a necessity to find the hardness of a MATERIAL as it can GIVE an indication of the strength and several other properties of a material. At the same time, it is important to AVOID damaging the material as that WOULD be a loss. Especially for a MANUFACTURED material.

The correct answer is (c) SET method hardness

For explanation I WOULD say: Hardness testing methods are processes to check the strength of the material. Rockwell hardness, Brinell hardness, Shore scleroscope hardness and Diamond pyramid hardness are typically used hardness TESTS. The set method is one of the methods used to DETERMINE the yield strength of a material.

Correct ANSWER is (c) Set

Easy EXPLANATION: The length AC is called the ‘set’ or GAGE length percentage. The graph REPRESENTS YIELD strength determination through the set method. The yield strength is represented at the point ‘B’ in the graph.

Right answer is (b) False

Explanation: USUALLY, the PREFERRED method of determining yield strength can be used. It is not fixed. The two METHODS typically used to find the yield strength are set method and EXTENSION under load method.

Correct choice is (d) 0.5

To elaborate: The fatigue limit is different for different MATERIALS. For the MATERIAL steel, the fatigue limit is around 0.5 of its ultimate TENSILE strength. For materials that are non-ferrous in NATURE, the fatigue limit can 0.3 or 0.4 of its ultimate tensile strength.

The correct answer is (a) lowest

The EXPLANATION: In an IZOD test, the material is first notched. Then it is clamped in heavy jaws, where the NOTCH level is with the top and facing the pendulum. After the pendulum is released from a CERTAIN height, it hits the material at the lowest point of its path.

Right choice is (d) 0.002

The BEST EXPLANATION: The extensions under load METHOD consists of two sections. First is elongation depending on the modulus of elasticity of object and expected yield strength and the second involves ADDING an extra elongation of 0.002 inch PER inch gage length.

Right option is (d) the particular stress where a MATERIAL shows specified elongation under a load

The BEST explanation: The yield strength of a material is the particular stress where a material shows specified elongation under a load. The elongation of a material is the CHANGE in LENGTH before being affected by stress to after.

Right choice is (B) 10^-6 to 10^-9 cm

For EXPLANATION I would say: Different types of rays are classified based on their respective wavelengths. The wavelength BRACKET in which the rays are considered to FIT the category of X-rays is from 10^-6 to 10^-9 centimeters.

Correct option is (a) reduction

To explain I would SAY: Corrosion of a material is not a DESIRABLE quality. This is because even a small amount of it can cause a reduction of fatigue LIMIT. Even flaws like lack of uniform cross-section in the specimen can have the same effect.

Correct option is (c) The amount of stress, a material can TOLERATE REPEATEDLY without failure

Easy explanation: The fatigue stress of a material is the stress it can tolerate several TIMES, without resulting in any failure. Each material has that fatigue stress and if it is CROSSED it is unsafe to load the material FREQUENTLY.

Right answer is (a) True

For explanation I would SAY: This STATEMENT is true. In fact, it is true for both the Izod impact test and CHARPY impact test. Once the pendulum hits a specimen, it’s SWING decreases significantly DUE to interruption in its path.

Right option is (d) 8

To elaborate: In the EXPERIMENTAL setup of the torsion TEST, there are two clamps PRESENT. The two clamps SECURE the wire in between them. The distance between the two camps in the machine is EIGHT inches.

Right option is (a) 180°

Easiest explanation: The usual ANGLE with which the TEST specimen should be BENT in the bending test is 180°. This is over a pin that has the same diameter as that of the test specimen being used in the experiment. CRACKING should be AVOIDED.

The correct option is (d) Charpy TEST

Best EXPLANATION: The method commonly preferred these days is the Charpy IMPACT test. The Izod impact test has ALSO been extensively used in the past. It is rarely used for testing materials/specimen these days.