past MCQs Flashcards
tables presents main regions of electromagnetic spectrum numbered parts
radiowave, 1, 2, 3, x - rays, 4
1 = infrared 2 = visible 3 = ultraviolet 4 = gamma rays
the region of the visible spectrum which has the greatest penetration of human tissue is
red
the impulse principle used to reduce RTA accident through
seatbelt
crumple zone
collapsible steering wheel
air bags
3 important components of laser system
active medium
excitation mechanism
cavity
True of false
the active medium determines the type of the wavelength that can be emitted from the laser devise
true
the active medium can be
solid
liquid
gas
plasma
laser radiation characterization are
coherent
monochromatic
collimated
the type of wavelength can be used in vision correction is
ultraviolet
the depth to which laser light penetrates into tissue depends on
wavelength of laser light
laser energy may interact with biological tissue in a number of ways. which of the following is the most important type of interaction in terms of laser ability to alter target tissue
absorption
which of the following wavelength exhibits the least amount of absorbance into tissue?
a) 250nm
b) 532nm
c) 700nm
d) 1064nm
e) 10600nm
e) 10600nm
the following categories of electromagnetic radiation are arranged in the order of increasing frequency
infra red, visible, microwaves, ultraviolet, x rays
which of the following is not a vector? displacement mass velocity momentum acceleration
mass
which of the following is a scalar? acceleration energy force momentum velocity
energy
which of the following is not a vector? displacement time velocity force acceleration
time
the frequency of a wave is
the number of waves passing a fixed point in one second
low frequencies penetrate
furthest into biological tissue
wavelength is defined as
the distance between each repeating element of the wave
the ___ of a wave is the number of ___ that pass a fixed point in one second
frequency
cycles
the energy of a wave is
directly proportional to
inversely proportional to
directly proportional to its frequency
the mechanical property of impulse has important implications for the severity of injuries caused in road traffic accidents. impulse is defined as
change in momentum
impact forces in road traffic accidents can be reduced by
increasing interaction time over which the impulse occurs
the mechanical advantage of class II lever system can be equal to 1 less than 1 both of the above none of the above
none of the above
laser radiation has the following properties
a) it is produced by stimulated emission of radiation
b) collimated
c) monochromatic
d) coherent
e) all of the above
all of the above
clinically useful lasers produce
a) mid-infrared radiation
b) near infrared radiation
c) UV radiation
d) visible radiation
e) all of the above
e) all of the above
in road traffic accident. which of the following is true.
a) injuries can be avoided if the impulse is increased
b) injuries can be avoided if the interaction time is reduced
c) internal injuries often result from the inertia of the internal organs
d) active head restraints utilise the impulse principle
e) collapsible steering columns are designed primarily to prevent head injuries
c) internal injuries often result from inertia of internal organs
impulse principle is described by
a) newton’s first law of motion
b) newtons second law of motion
c) both of the above
d) none of the above
c) both of the above
impact force on the occupant of a vehicle during a traffic accident is reduced by
increase time of impulse
impulse is defined as
force x interaction time
change in momentum
product of mass and acceleration is
force
low frequencies penetrate
furthest into biological tissue
which one of these has the lowest energy UV gamma rays red light microwaves x - rays
microwaves
list precautions that must be taken for microshock sensitive patients
electrical equipment should be earthed
patient should NOT be grounded
list conditions that consider someone to be microshock sensitive
have artificial pacemaker
catheters
internally placed conductor
stress unit
N/m^2
strain unit
ε
define compression
intermolecular forces push together, causing the material to deform and thus reducing the volume of the material
define tension
causes stretching and elongation of material along axis of load applied
shear stress definition
stress acts parallel to surface
deformed by slippage of material
The _______ of a force is a measure of the ability of the force to produce a turning effect about an axis.
moment
Airbags, collapsible steering columns and padded interiors all use the ___________ Principle to reduce injuries in road traffic collisions
impulse
Acceleration is the rate of change of ______________.
velocity
If 5 mA is the maximum harmless current and the resistance of dry skin is 100,000 ohms, what is the maximum voltage that will be safe to the body?
500V
torque
distance x force
skin impedance is ___ proportional to frequency
inversely
give value of mechanical advantage of class I lever
less than greater than or equal to 1
give value of mechanical advantage of class II lever
greater than 1
give value of mechanical advantage of class III lever
lesser than 1
elastic deformation
when there is a change in length, but the material can return to its original length.
plastic deformation
when the material is beyond its elastic limit and the material can no longer return to its original length
The adverse effect of an electric shock to an individual is primarily determined by what factor?
Amount of current flowing through the body
