3.4u Day 3 Homework

Question 1

Which of the following is in the weld defect category Imperfect Shape

Answer 1

Undercut

CCSLIM- Cracks, Cavities, Solid inclusions, Lack of fusion, Imperfect Shape, Miscalaneous

Question 2

A 2.5MHz compression probe will produce the longest wavelength in which medium?

Answer 2

Water

Question 3

Which of the following is a correct description of a wavelength

Answer 3

The distance travelled by the soundwave during one complete cycle

Question 4

Which term means the opposite of Permeability?

Answer 4

Reluctance

Question 5

Which of these values does the UV light output have to have a minimum of?

Answer 5

1000μW/cm2

μW - Microwats

Question 6

With the aid of a diagram of a weld show the following:
Weld cap
Root
Root gap
Weld toe
Fusion zone
HAZ
Throat thickness
Effective throat thickness

Question 7

Show with the aid of a diagram the different zones in an ultrasonic beam and indicate which zone will provide the greatest accuracy for testing.

Question 8

Explain with the aid of sketches the “Piezo Electric” effect.

Question 9

Draw an Hysteresis Loop and indicate the following:

Saturation Points
Retentivity Points
Coercivity Points

Question 10

Explain the difference between hard ferromagnetic and soft ferromagnetic materials.

Answer 10

Hard ferromagnetic materials are suitable for permanent magnetic applications due to their ability to retain magnetization, while soft ferromagnetic materials are better for applications requiring rapid changes in magnetization due to their ease of magnetization and demagnetization.

Hard Ferromagnetic ( difficult to magnetize)
Hight retentivity
High Remanence
High Reluctance
High coercivity to demagnetise

Soft ferromagnetic (easy to magnetise)
Low retentivity
Low remanence
Low reluctance
Low coercivity to demagnetise

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