Coke deposits on the inner walls of a heater tube produce __________ when the tube is tapped lightly with a hammer?
a) a clear ringing tone
b) a dull sound
c) chimes
d) a vibrating sound
e) a whistling sound
Answer: B
Coke deposits on the inner walls of a heater tube produce __________ when the tube is tapped lightly with a hammer?
a) a clear ringing tone
b) a dull sound
c) chimes
d) a vibrating sound
e) a whistling sound
Answer: B