P10-1 task 2

Question 1

which type of clothing offers the best protection against radiation from the arc?

1. cotton
2. polyester
3. nylon
4. wool

Answer 1

d. wool

Question 2

when heated, trichlorethylene and tetrachlorethylene break down to form highly toxic gas called

1. ozone
2. phosgene
3. hydrogen sulphide
4. carbon monoxide

Answer 2

b. phosgene

Question 3

which type of extinguisher is used for electrical fires?

1. Class A
2. Class B
3. Class C
4. Class D

Answer 3

c. Class C

Question 4

what percentage of oxygen must air contain to maintain proper breathing?

1. 10%
2. 14%
3. 18%
4. 22%

Answer 4

c. 18%

Question 5

which of the following metals have highly reflective surfaces that increase the radiation hazards even more during GTAW?

1. low and high carbon steel
2. Aluminum and Stainless Steels
3. copper and bronze
4. silicone and cast iron

Answer 5

b. Aluminum and Stainless Steels

Question 6

give two reasons why weld cable should not carry currents higher than their rated capacity.

Answer 6

• causes of overheating and rapid deterioration of insulation
• uneconomical

Question 7

although shielding gases such as argon and helium are non-toxic they can still pose a hazard because they

1. react to certain metals to reduce toxic fumes
2. are extremely flammable
3. entrap dust particles which can damage your lungs
4. displace are in confined areas and interfere with proper breathing

Answer 7

d. displace are in confined areas and interfere with proper breathing

Question 8

the filter plate for GTAW should be

1. one to two shades darker than for SMAW
2. one to two shades lighter than for SMAW

Answer 8

a. one to two shades darker than for SMAW

Question 9

before you can install a welding machine you must ensure that it is

1. attached to the electrode holder
2. turned on
3. properly grounded
4. covered with a protective screen

Answer 9

c. properly grounded

Question 10

Why must you always inspect the filter plate in your helmet before welding?

Answer 10

You must always inspect the filter plate in your helmet to check for cracks that could permit ultraviolet or infrared rays to penetrate your eyes. If the lens is cracked or damaged in any way replace it before proceeding.

Question 11

to protect your hearing against high or continuous noise levels you should wear

1. dry cotton in your ears
2. approved ear plugs
3. ear flap
4. stereo headphones

Answer 11

b. approved ear plugs