Explore topic-wise MCQs in Mechanical Engineering.

This section includes 335 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.

251.

When a longitudinal wave is incident upon an inclined interface between zero degrees and the first critical angle:

A. The sound beam is totally reflected
B. Only shear waves are produced in the second material
C. Shear waves and longitudinal waves are produced in the second material
D. Only longitudinal waves are produced in the second material
Answer» D. Only longitudinal waves are produced in the second material
252.

Where possible, circular magnetisation is preferable to longitudinal magnetization because:

A. Less current is required
B. Stronger fields are obtained
C. Fewer confusing secondary poles are produced
D. None of the above is true
Answer» E.
253.

On the area-amplitude ultrasonic standard test blocks, the flat-bottomed holes in the blocks are:

A. All of the same diameter
B. Different in diameter, increasing by 1/64 inch increments from the No. 1 block to the No. 8 block
C. Largest in the No. 1 block and smallest in the No. 8 block
D. Drilled to different depths from the front surface of the test block
Answer» C. Largest in the No. 1 block and smallest in the No. 8 block
254.

A leakage field is strongest when a discontinuity interrupts the magnetic flux lines at an angle of:

A. 0o
B. 45o
C. 90o
D. 180o
Answer» D. 180o
255.

Highest sensitivity to fine surface cracks would be obtained by which of the following techniques?

A. Residual field, wet method
B. Residual field, dry method
C. Continuous field, wet method
D. Continuous field, dry method
Answer» D. Continuous field, dry method
256.

Which of the following methods might be used to reduce attenuation losses in an ultrasonic test?

A. Use a shorter wavelength
B. Use a lower frequency transducer
C. Change from longitudinal waves to shear waves
D. Change to a coarser grained test piece
Answer» C. Change from longitudinal waves to shear waves
257.

An ultrasonic display which shows a cross section of the test piece and any flaws which are found are called:

A. A scan
B. B scan
C. C scan
D. Orthogonal view
Answer» C. C scan
258.

The fact that gases, when bombarded by radiation, ionise and become electrical conductors make them useful in:

A. X ray transformers
B. X ray tubes
C. Masks
D. Radiation detection equipment
Answer» E.
259.

When conducting an immersion test, the water path distance must be controlled so that:

A. Spurious signals are not created by surface waves on the test piece
B. The (water path distance)/(diameter) ratio does not result in asymmetric standing waves
C. The test piece discontinuity indications appear between the first front and first back surface echos
D. The second front surface echo does not appear on the CRT screen between the first front and first back surface echos
Answer» D. The second front surface echo does not appear on the CRT screen between the first front and first back surface echos
260.

The angle formed by an ultrasonic wave as it enters a medium of different velocity than the one from which it came and a line drawn perpendicular to the interface between the two media is called:

A. The angle of incidence
B. The angle of refraction
C. The angle of diffraction
D. The angle of reflection
Answer» C. The angle of diffraction
261.

The formula, NI = 45000/(L/D), gives proper magnetising current for a coil, regardless of coil size as long as:

A. The test piece is not larger than 1/10 the cross sectional area of the coil
B. AC current only is used
C. The test piece essentially fills the coil
D. The test piece is held tightly against the coil
Answer» B. AC current only is used
262.

A technique used to find transverse discontinuities at the ends of longitudinally magnetised bars by the use of transient currents is called:

A. A coil technique
B. A fast break technique
C. A yoke technique
D. A head shot
Answer» C. A yoke technique
263.

What rule describes the direction of current flow (+ to -) when lines of magnetic force surround a conductor?

A. Left hand rule
B. Right hand rule
C. Flux density rule
D. Reluctance rule
Answer» C. Flux density rule
264.

The field in a section of pipe being magnetised by means of a central conductor is stronger at:

A. The ends of the pipe
B. The outer surface of the pipe
C. The inside surface of the pipe
D. The middle of the pipe wall
Answer» D. The middle of the pipe wall
265.

When contouring an angle beam wedge for a convex surface, an undesirable result of a wedge which is contoured too well might be:

A. Production of unwanted surface waves
B. Greater beam divergence due to larger contact area
C. Lower beam divergence due to larger contact area
D. Overly efficient coupling of sound beam into test part
Answer» B. Greater beam divergence due to larger contact area
266.

When a magnetic field is induced in a part with prods spaced 150mm apart, the field is:

A. Solenoidal
B. Circular
C. Longitudinal
D. Distorted trapezoidal
Answer» C. Longitudinal
267.

The most important factor required for the proper interpretation of ultrasonic test results is:

A. The ultrasonic signal amplitude
B. A knowledge of the test specimen material and its construction
C. A knowledge of the ultrasonic instruments operating characteristics
D. The ultrasonic signal location
Answer» C. A knowledge of the ultrasonic instruments operating characteristics
268.

The film processing step in which the undeveloped silver bromide is removed from the film emulsion is called:

A. Development
B. Stop bath
C. Fixing
D. Rinsing
Answer» B. Stop bath
269.

A continuous linear indication along the edge of a new fillet weld would most likely be a:

A. Crater crack
B. Fatigue crack
C. Stress corrosion crack
D. Heat affected zone hydrogen crack
Answer» E.
270.

The process of loading more than one film into a cassette is known as the technique:

A. Single film technique
B. Multiple film technique
C. none
D. none
Answer» C. none
271.

With current flowing from + to - in a coil, a longitudinal field is created. Which of the following may be used to establish the direction of the magnetic field?

A. Left hand rule
B. Right hand rule
C. Ohms law
D. There is no relevant law
Answer» C. Ohms law
272.

The flux within and surrounding a magnetised part or around a conductor carrying a current is known as:

A. Saturation point
B. Magnetic field
C. Ferromagnetic
D. Paramagnetic
Answer» C. Ferromagnetic
273.

Why should one avoid using a high velocity flow of a wet testing media over the test area

A. It may wash away a fine or lightly held indication
B. This is not a problem
C. It may splash particle into eyes
D. None of the above are correct
Answer» B. This is not a problem
274.

In which magnetizing method is the current passed directly through the part, thereby setting up a magnetic field at right angles to the current flow?

A. Longitudinal magnetization
B. Coil magnetization
C. Central conductor magnetization
D. None of the above
Answer» E.
275.

According to ASMT E709-95 alternating current electromagnetic yokes should give a lifting force of at least:

A. 1.5 kg
B. 2.5 kg
C. 3.5 kg
D. 4.5 kg
Answer» E.
276.

The space within and surrounding a magnetized part of a conductor carrying a current is known as:

A. Saturation point
B. Magnetic field
C. Ferromagnetic
D. Paramagnetic
Answer» C. Ferromagnetic
277.

Compared to the magnetic field strength at the outer surface, the magnetic field strength, at the centre of a hollow, nonmagnetic conductor carrying DC current is:

A. I/D
B. The same
C. Zero
D. Need more information to determine
Answer» D. Need more information to determine
278.

Subjecting the part to a magnetic field that is constantly reversing in polarity and gradually diminishing in strength accomplishes which of the following:

A. Magnetises the part
B. Removes residual field from the part
C. Soaks in the flux density
D. Helps find deep lying defects
Answer» C. Soaks in the flux density
279.

According to ASTM E709-95, Table 3., direct current electromagnetic yokes must have a lifting force of at least:

A. 15 kg (33 lb)
B. 16 kg (36 lb)
C. 17 kg (38 lb)
D. 18 kg (40 lb)
Answer» E.
280.

The primary reason for using water rather than oil as a suspension medium for wet method baths is that

A. Water is more chemically inert than oil
B. Bath flammability hazards are eliminated
C. Water has the capability to dissolve the needed rust inhibitors
D. Water baths may be used at a lower temperature than oil baths
Answer» C. Water has the capability to dissolve the needed rust inhibitors
281.

The magnetic particles are noticed to bunch in some fillet areas and stand on end on the edge of a part being magnetized. These observations indicate that the:

A. Particle concentration is too low
B. Flux density is excessive
C. Flux density is too low
D. Magnetizing current should be changed form AC to DC
Answer» C. Flux density is too low
282.

When using the wet continuous method, the flow of suspension from the hose should be shut off:

A. Immediately after applying the current
B. Immediately before applying the current
C. While the current is flowing
D. Thirty seconds before applying the current
Answer» D. Thirty seconds before applying the current
283.

Which of the following describes the best technique for applying dry magnetic particles to a test piece?

A. Dip the test piece in a tank of dry particles while current is flowing
B. Apply with an electrostatic spray gun at approximately 30 PSIG
C. Gently pour the powder onto the test piece
D. Shake or dust the powder onto the test piece with minimum velocity
Answer» E.
284.

According to AST M E709-95 and API, after removing magnetization of parts after examination, the residual magnetism shall not exceed (1 gauss = 0.0001 tesla):

A. 3 10-4T (3gauss)
B. 4 10-4T (4 gauss)
C. 6 10-4T (6gauss)
D. 8 10-4T (8 gauss)
Answer» B. 4 10-4T (4 gauss)
285.

To provide reliability and reproducibility in magnetic particle testing, written procedures should include:

A. Location of the coil and current for each magnetization
B. Requirements for ammeter calibration
C. Type and concentration of the particles
D. All of the above
Answer» E.
286.

Which of the following types of intensifying screens are not used in industrial radiography?

A. Lead
B. Fluorescent
C. Silver halide
D. All of the above
Answer» D. All of the above
287.

According to ASTM E709-95, with wet continuous magnetization technique, the duration of magnetization current is of the order of:

A. 0.5 sec
B. 1.0 sec
C. 1.5 sec
D. 2.0 sec
Answer» B. 1.0 sec
288.

The important difference between AC and DC current for magnetic particle testing purposes is:

A. The skin effect caused by DC adds mobility to the magnetic particles
B. The resulting AC magnetic fields are more difficult to demagnetize
C. The DC magnetic fields are more penetrating
D. The AC magnetic fields are stronger
Answer» D. The AC magnetic fields are stronger
289.

Gamma ray or high voltage X ray radiography, using film without lead screens, is likely to result in:

A. Mottling of the film
B. Increased geometric unsharpness
C. No apparent difference, but increased exposure time
D. No apparent difference, but decreased exposure time
Answer» B. Increased geometric unsharpness
290.

According to ASTM E709-95 with prod technique, the prods shall be tipped if the open circuit voltage is over:

A. 10 V
B. 15 V
C. 20 V
D. 25 V
Answer» E.
291.

For detection of longitudinal discontinuities a 7.6 cm (3 inches) diameter bar is magnetized in:

A. The longitudinal direction
B. The circular direction
C. The clockwise direction
D. None of the above directions
Answer» C. The clockwise direction
292.

Which of the following techniques would probably reduce the amount of scattered radiation reaching the film during a radiographic exposure?

A. Using a finer grained film
B. Using a filtered X ray beam
C. Removing lead screens
D. All of the above
Answer» C. Removing lead screens
293.

If the required exposure time for a 50 Curie Ir-192 source is 4 minutes, what exposure time would be required at 25 Curie source:

A. 4 minutes
B. 8 minutes
C. 2 minutes
D. 16 minutes
Answer» C. 2 minutes
294.

If it were necessary to radiograph 18 cm (7 in.) thick steel product, which of the following gamma ray sources would most be used?

A. Cs 137
B. Tm 170
C. Ir 192
D. Co 60
Answer» E.
295.

In order to increase latitude so that thick and thin portions may be radiographed at reasonable viewing densities simultaneously:

A. Fluorescent screen should be employed
B. Led screens should be at least 5 mm thick
C. The cassette may be loaded with two separate films of different speeds
D. Radiograph the object at low energy
Answer» D. Radiograph the object at low energy
296.

Which of the following is NOT a liquid vehicle in which particles are suspended in magnetic particle testing:

A. Water treated with a wetting agent
B. Kerosene
C. Gasoline
D. Water treated with antifoam
Answer» D. Water treated with antifoam
297.

Which type of gamma ray source would be used to radiograph a weld in 150 mm thick steel plate?

A. Ir-192
B. Co-60
C. Tm-170
D. Cs-137
Answer» C. Tm-170
298.

An exposed radiographic film which transmits 1% of the light incident on it has what density:

A. 1.0
B. 2.0
C. 99.0
D. 0.5
Answer» D. 0.5
299.

When using a radioactive isotope in making a radiograph, we can express the equation for exposure as Ci T. In this equation , Ci stands for:

A. Current through tube
B. Intensity in curies or becquerels
C. Degree of contrast
D. Coarseness of the film
Answer» C. Degree of contrast
300.

According to ASTM E709-95 when dry particles are used magnetic particle testing shall not be performed on the surface of parts whose temperature exceeds:

A. 57 C
B. 79 C
C. 158 C
D. 136 C
Answer» B. 79 C