ACOUSTIC AND ELECTRICAL PROPERTIES OF WOOD

Question 1

• is in relation to sound or it
  refers to its capacity to absorb
  or reflect sound and reduce
  vibrations

Answer 1

Acoustic Property

Question 2

• ability to absorb and prevent
  reflections of sound

Answer 2

Acoustic Property

Question 3

• has a high damping capacity; therefore, it is an ideal material for structural components in which vibration is unwanted

Answer 3

Acoustic Property

Question 4

WOOD IS ACOUSTIC:

Answer 4

1. Presence of pores, vessel lines, and microcapillaries
2. Fabricated holes
3. Fabricated striations

Question 5

_________ wood is effective as a sound-absorbing material because it exhibits a small specific impedance (Smardzewski et al. (2014)

Answer 5

high porosity

Question 6

__________ is essential in the design and construction of musical
instruments, The placement, size, and shape of these holes
influence the resonance, tone, volume, and overall acoustic
performance of the instrument

Answer 6

fabricated holes

Question 7

__________ is a craftsmanship of the instrument, including how the wood is treated, shaped, and assembled, also plays a significant
role in determining the final sound.

Answer 7

fabricated striations

Question 8

SOFTWOOD has a _____ sound absorption at high frequencies;
effective in reducing echoes and
_____ sound reflection;
better for diffusing sound.

Answer 8

high; moderate

Question 9

HARDWOOD has a ____ sound absorption overall; absorbs less high-frequency sound and ____ sound reflection especially at lower frequencies.

Answer 9

lower; high

Question 10

_______ are better in reflecting soundwaves

Answer 10

softwoods

Question 11

_______ are sustain and creates more sharp tone

Answer 11

hardwood

Question 12

______ are less sustain and has a softer tones

Answer 12

softwood

Question 13

• Unit used to measure sound, named after Alexander Graham
  Bell

Answer 13

DECIBEL

Question 14

______ decibel is the normal level for human.

Answer 14

60-70

Question 15

_____ is the maximum for safe volume level for ears.

Answer 15

80 dB

Question 16

_____ for breathing and _____ for whisper

Answer 16

10 dB; 15 dB

Question 17

• Capacity of wood to withstand induced vibration by sound waves transmitted from the outside forces

Answer 17

RESONANCE OF WOOD

Question 18

• Deals with the movement or flow of energy in the form of electric charge such as electrons.

Answer 18

ELECTRICAL PROPERTIES OF WOOD

Question 19

Movement of electricity can be classified in two different ways:

Answer 19

1. Direct Current (DC) and
2. Alternating Current (AC)

Question 20

• flow of electric charge in one direction.

Answer 20

Direct Current (DC)

Question 21

• flow of electric charge that frequently reverses direction.

Answer 21

Alternating Current (AC)

Question 22

DIRECT CURRENT (DC) ELECTRICAL
PROPERTIES OF WOOD:

Answer 22

a. Resistivity
b. Conductivity

Question 23

• exhibits how strongly it resists the flow of electric current.

Answer 23

Resistivity

Question 24

• as the MC of wood increases from ovendry to FSP, resistivity decreases.

Answer 24

Resistivity

Question 25

- as the MC continue to increase from FSP to complete MC saturation in wood, the smaller its electrical resistivity (Glass,et al., 2010)

Answer 25

Resistivity

Question 26

high MOISTURE CONTENT, low RESISTIVITY (vice versa)

Answer 26

low MOISTURE CONTENT, high RESISTIVITY

Question 27

– reciprocal of electrical resistivity.

Answer 27

Conductivity

Question 28

- wood’s ability to conduct electric current.

Answer 28

Conductivity

Question 29

- electrical conductivity of wood increases as temperature increases unlike the conductivity of metal.

Answer 29

Conductivity

Question 30

- the wood conductivity is greater along the grain direction compared to the direction across the grain, and greater in the radial section than in the tangential section (Glass, et.al., 2010).

Answer 30

Conductivity

Question 31

The AC electrical properties of wood deals with the _____ constant.

Answer 31

dielectric

Question 32

- also known as relative permittivity

Answer 32

Dielectric Constant

Question 33

- is defined as the ratio of the permittivity of a substance to the permittivity of free space

Answer 33

Dielectric Constant

Question 34

The dielectric constant of wood is basically the __________________ stored in wood in the form of electric polarization when the material is in a given electric field

Answer 34

measure of energy per unit volume

Question 35

FACTORS AFFECTING ELECTRICAL PROPERTIES OF WOOD:

Answer 35

1. Moisture Content 2. Temperature 3. Wood Type 4. Grain Orientation