G10 Optical Instruments Flashcards
is a hand-held tool used to view smaller objects
one of the simplest optical instruments and is comprised of just a single converging lens
magnifying glass
As the object moves _ to the eye, the angle increases and as a result, a _ image is observed.
closer, larger
However, the eye cannot focus on an object closer than 25 cm. This is referred to as the
near point
However, the eye cannot focus on an object closer than 25 cm. This is referred to as the
near point
To increase the apparent size of the object being observed, a _ _ can be placed in front of the eye while the object is positioned at the focal length of the lens.
converging lens
In this setup, the virtual image is at _, making the muscle of the eye more relaxed and the image more comfortable to view.
infinity
The image formed by the magnifying glass is always _, _, and _
virtual, upright in position, and enlarged.
angular magnification
efficiency of a magnifier
given by the ratio of the angle with the magnifier (θ) to the angle without the magnifier (θ0)
If the object is at the near point of the eye, the maximum angular magnification is given by this equation
m(max)=1+25cm/f
regular angular magnification
m=θ/θ(0)
angle with the magnifier (θ) to the angle without the magnifier (θ0).
The object must be placed at the focal point of the lens for the image to be at infinity. This relationship is expressed by the equation
m=θ/θ0=25cm/f
angle with a magnifier
θ
angle without a magnifier
θ0
focal length
f
Higher magnification that cannot be provided by a simple magnifier can be achieved by using a combination of two lenses in a device
microscope, sometimes compound microscope
used to focus the object under the microscope with wide range of magnifications and a very short focal length which is usually less than one centimeter
objective lens
used to observe the object or specimen being studied. It usually has a magnification of 10 to 15 times and a focal length of a few centimeters
ocular lens
ocular lens is also called
eyepiece
The image formed by the _ lens, becomes the object for the _ lens.
objective, ocular
The object is placed outside the focal length of the objective which forms a _, _ and _ image that is at or inside the focus of the eyepiece
real, inverted and enlarged
The eyepiece which acts as a simple magnifier uses the image produced by the objective lens as its ‘_’.
object
The eyepiece which acts as a simple magnifier uses the image produced by the objective lens as its ‘object’. As a result, it produces a second image which is considered as the “_”.
final image
This second image that we observe is _, _, and _ compared to the original object.
virtual, inverted and very much enlarged
The angular magnification between the angular sizes of the virtual image as seen through the eyepiece and of the real image if viewed without the eyepiece is expressed by the equation below:
m=M(1)m(e)=[-L/f(o)][25cm/f(e)]
overall magnification of the compound microscope
m
lateral magnification of the objective lens
M(1)
angular magnification of the eyepiece
m(e)