Physics Questions
Explore questions in the Physics category that you can ask Spark.E!
Although scratch resistance and antireflection coatings are harder than CR39, they _____ lens impact resistance.
What type of lens can be tested before it is edged (uncut-finished stage)?
Chemical tempering: the smaller Na or Li ions are replaced by larger K ions, creating ________.
What is the advantage of heat tempering as compared to chemical?
True or False. Chemical treated glass can be drilled and grooved and pass the drop ball test. However, it is not recommended because edges can chip/crack leading to decreased impact strength.
Dispenser must keep records for ___ years after purchase of lenses to include name and address of purchaser.
_____ is used for photochromatic lenses.
Dress lens must be capable of withstanding the impact of a 5/8 inch steel ball weighting _____ oz dropped from a distance of ______ inches.
True or False? Plastic lenses must be safety tested after ARC is applied.
What type of lens is best to avoid? A) crown glassB) trivexC) polycarbonate D) CR-39
In chemical tempering, the lens is immersed in _______.
Heat treatment of glass lenses: can be confirmed by viewing the lens when placed between __________.
______ is used for clear and tinted crown glass.
In class we mentioned how polycarbonate lenses should be offered to all patients and recommended for all of the following except: A) patients with at-risk eye(s)B) patients purchasing safety eyewear C) patients purchasing sports wearD) childrenE) monocular patientsF) all the above are candidates
Polycarbonate lenses can safely be made thin as _____ to ____ mm. It is _____ density. It also has a high. Index, so thickness can be _______.
Plastic lenses are permissible to conduct _____ testing. Ex: ultex A
Which method of glass treatment causes the lens to NOT be as impact resistant. A) heat-treatmentB) chemically tempered
When testing ______ lenses, the lens manufacturer is responsible for batch testing. They can be edged without further testing.
A heat-treated glass lens shows a ______ cross pattern. Pattern does not need to be perfect.
Which glass treatment process is preferred? A) heat-treatmentB) chemical tempering