Microscope Picture
Microscope: - The microscope was invented by Antony van Leeuwen-Hoeck. It is
an instrument by which very small
things can be seen which are not seen by the Naked Eye.
A compound
microscope essentially consists of the following Parts.
Microscope With Parts Name
Parts of Compound Microscope
1.
The
Stand :- It comprises a “Heavy
Foot”, often shapes like a “Horse Shoe”, to
provide stability;
And the Limb which
bears the optical System. The limb is attached to the foot by a Hinged Joint so that the Microscope may
be set at a Comfortable Angle for the observer.
2.
The
Optical System :- It is mounted on the tube which is usually in Two Parts.
i.
An External
Tube which bears at its lower end a revolving Nose Piece in which
inter-changeable three objective lenses of various magnifications are fitted:
a.)
Low Power:- 10x
a.)
High Power:- 40x
b.) Oil
immersion:- 100x
Microscope Lenses 10x , 40x , and 100x oil
immersion
ii.
An Inner Draw Tube that carries the eye piece
(Magnification 10x) at its upper end
10x Wide Field Eye Piece (Magnification 10x)
NOTE:- The objective lenses can be
identified by magnification imprinted on them. In addition , oil – immersion
lens has a black rim around its lower end. It has been become customary for
the objective lenses to be marked with their magnifying power rather than
their focal length. The approximate equivalents are as follows:
Focal length (mm)
Magnification
2
100x
4
40x
16
10x
40 4x
Objective lenses –
low, high and oil – immersion lens
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3.
The
Body: - The whole assembly
is held in
position
by the body which
consists of Two Mechanisms:- The Coarse and Fine
Adjustments. With the help of these adjustments the height of the tube can
be adjusted in such a way so that the objective lens can be positioned at its optimal
working distance (i.e. its focal
length) from the object to be examined. The fine adjustment is usually
graduated in 1/50ths and each division corresponds to a
movement of 0.002 mm of the tube. It is used for accurate focusing.
Coarse and Fine Adjustment of Microscope
4.
The
Stage: - It is a platform that accommodates a glass slide on which the
object to be examined
is mounted. It is attached to the
limb immediately below the level of the objective lens and has an aperture in
the centre to permit light to reach the object. A Mechanical Stage is fitted to the fixed stage so that the object
may be moved from side to side and before backwards.
5.
The
Sub-Stage: - It lies beneath the stage
which can be lowered or raised by means
of a screw.
The
Stage is fitted with a Condenser and
Iris Diaphragm.
(i)
The Condenser consists of two lenses, it serves
to condense the rays of light and to focus them on the object. The height of
condenser and, therefore, the focus of light can be varied.
(ii) Immediately
below the condenser is the Iris Diaphragm
that can control the amount of light reaching the object.
Sub - Stage (Condenser with Iris-Diaphragm)
6.
The
Mirror: - Fitted to the tail piece below the
condenser is a hinged double reflecting
mirror
which is
plane on one side and concave on the other. The plane side of the mirror is
used when the condenser is used. The mirror can be tilted and rotated in all
directions.
Digital Mirror and Simple (Sunlight) Mirror
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