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Laser Exam Questions and Verified Answers
Which best characterizes laser waves:
A - Quasichromatic, non-collimated, non-coherent
B - Multichromatic, non-collimated, non-coherent
C - Monochromatic, collimated, coherent
Ans: C - Monochromatic, collimated, coherent
A laser pulse cycles between ON for 5 ms and OFF for 20 ms. What is the duty
cycle?
A - 10%
B - 20%
C - 25%
D - 40%
Ans: B - 20%
Which of the following lasers is used on hard tissue?
A - CO2 9,250 nm
B - THOR
C - Nd:YAG 1064nm
D - Diodes 810-1064nm
Ans: A - CO2 9,250 nm
What is the definition of Power?
A - Ability to perform work, expressed in joules (J)
B - Amount of work performed per unit time, expressed in watts (W)
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C - A measurement of the total amount of time that the pulse is emitted
D - The power of a single, brief emission from a laser programmed for pulsed
behavior rather than continuous operation
Ans: B - Amount of work performed per unit time, expressed in watts (W)
When do you test fire a laser?
A - When it is a new laser
B - Always test fire before use
C - Depends on the laser
D - Never
Ans: B - Always test fire before use
Electromagnetic waves transport energy through
a. Empty Space
b. A material medium
c. Matter
d. Mechanical waves
Ans: a. Empty Space
Which is not a way lasers interact with tissues?
a. Reflection
b. Transduction
c. Scattering
d. Absorption
Ans: b. Transduction
Which laser wavelewngths can penetrate to the retina of the eye and cause
damage?
a. Diode wavelengths
b. Er:YAG
c. Nd:YAG
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d. BothA&C
Ans: d. BothA&C
Light-induced fluorescence can be used for
a. Caries detection
b. Mucosal evaluation
c. Pain relief
d. BothA&B
Ans: d. BothA&B
Continuous wave lasers cause increased char of tissue compared to ultraspeed
or superpulse lasers. Ultraspeed or superpulse lasers cause minimal heat spread
compared to continuous wave lasers.
a. Both statements are true
b. Statement 1 is true; statement 2 is false
c. Both statements are false
d. Statement 1 is false; statement 2 is true
Ans: a. Both statements are true
Which of the following is NOT a tissue chromophore that absorbs a laser
wavelength?
a. Water
b. Sodium (not at the dental wavelength)
c. Hemoglobin
d. Melanocytes
Ans: b. Sodium (not at the dental wavelength)
Which of the following statements about heat transfer is INCORRECT?
a. Laser irradiation is heat transfer by electromagnetic waves
b. High volume suction is an example of convection
Laser Exam Questions and Verified Answers
Which best characterizes laser waves:
A - Quasichromatic, non-collimated, non-coherent
B - Multichromatic, non-collimated, non-coherent
C - Monochromatic, collimated, coherent
Ans: C - Monochromatic, collimated, coherent
A laser pulse cycles between ON for 5 ms and OFF for 20 ms. What is the duty
cycle?
A - 10%
B - 20%
C - 25%
D - 40%
Ans: B - 20%
Which of the following lasers is used on hard tissue?
A - CO2 9,250 nm
B - THOR
C - Nd:YAG 1064nm
D - Diodes 810-1064nm
Ans: A - CO2 9,250 nm
What is the definition of Power?
A - Ability to perform work, expressed in joules (J)
B - Amount of work performed per unit time, expressed in watts (W)
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C - A measurement of the total amount of time that the pulse is emitted
D - The power of a single, brief emission from a laser programmed for pulsed
behavior rather than continuous operation
Ans: B - Amount of work performed per unit time, expressed in watts (W)
When do you test fire a laser?
A - When it is a new laser
B - Always test fire before use
C - Depends on the laser
D - Never
Ans: B - Always test fire before use
Electromagnetic waves transport energy through
a. Empty Space
b. A material medium
c. Matter
d. Mechanical waves
Ans: a. Empty Space
Which is not a way lasers interact with tissues?
a. Reflection
b. Transduction
c. Scattering
d. Absorption
Ans: b. Transduction
Which laser wavelewngths can penetrate to the retina of the eye and cause
damage?
a. Diode wavelengths
b. Er:YAG
c. Nd:YAG
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d. BothA&C
Ans: d. BothA&C
Light-induced fluorescence can be used for
a. Caries detection
b. Mucosal evaluation
c. Pain relief
d. BothA&B
Ans: d. BothA&B
Continuous wave lasers cause increased char of tissue compared to ultraspeed
or superpulse lasers. Ultraspeed or superpulse lasers cause minimal heat spread
compared to continuous wave lasers.
a. Both statements are true
b. Statement 1 is true; statement 2 is false
c. Both statements are false
d. Statement 1 is false; statement 2 is true
Ans: a. Both statements are true
Which of the following is NOT a tissue chromophore that absorbs a laser
wavelength?
a. Water
b. Sodium (not at the dental wavelength)
c. Hemoglobin
d. Melanocytes
Ans: b. Sodium (not at the dental wavelength)
Which of the following statements about heat transfer is INCORRECT?
a. Laser irradiation is heat transfer by electromagnetic waves
b. High volume suction is an example of convection
