Microscope, Magnification and Electromagnetic spectrum Flashcards
Define Magnification
the number of times larger an image of an object is than the real size of an object.
Define Resolution
the ability to distingush between two objects very close together.
What is the relationship between resolution and an image?
the higher the resolution of an image, the greater the detail can be seen.
What is the formula for magnification? [2]
- Magnification = image size / actual size
- Magnification= magnification of eyepiece lens x magnification of objective lens
Name 3 types of micrscope.
- Light Microscope
- Transmission Electron Microscope (TEM)
- Scanning Electron Microscope (SEM)
Name the source of radiation use in light microscope.
Light
Name the source of radiation use in TEM & SEM.
Electron
Define Micrographs
Photo taken with the help of microscope.
An example of micrographs
- Photomicrographs (using light)
- Electromicrographs (using electron)
How does TEM see the specimen?
Beam of electrons is shot to the specimen and pass through the specimen and only parts the the electron is transmitted can be seen
How does SEM see the specimen?
Beam of electron is shot to scan the surface of the structure and only the reflected beam is observe.
What is the advantage and disadvantage of SEM?
Advantage: 3D appearance
Disadvanntage: Low resolution
What is the advantage and disadvantage of TEM?
Advantage: High resolution
Disadvanntage: 2D appearance
Name the lenses found in TEM & SEM.
Electrostatic lens
Name the lenses found in a light microscope
Glass lens
What colour image produce when using a light microscope?
Coloured Image
What colour image produce when using TEM/SEM?
Black & White Image
What stain are use for light microscope?
Coloured Dyes
What stain are use for electron microscope?
Heavy Metal dyes
ex: Uranium / Lead
What is the maximum resolution for light microscope?
200 nm
What is the Maximum Resolution for electron microscope?
0.5 nm
What is the relationship between resolution and wavelength?
Shorter the wavelength, Higher the resolution, Greater the detail can be seen.
What is the wavelength of radiation use for light microscope?
about 400-700 nm
What is the wavelength of radiation use for electron microscope?
about 0.005 nm
What specimen can be seen under a light microscope?
Living Specimen
What specimen can be seen under a electron microscope?
Non-living specimen / Dead specimen
What is an eye piece graticule?
Small scale that is place in a microscope eyepiece
Name all parts of light microscope. [14]
- eyepiece
- objective lens
- nose
- arm
- stage
- stage clamps
- mirror
- fine focus adjustor
- coarse focus adjustor
- condenser lens
- iris diaphragm
- condenser iris diaphargm
- condenser
- base
What is a stage micrometer?
[2]
- Very small, accurately drawn scale.
- Engraved on a microscope slide.
Name all the electromagnetic spectrum from the longest wavelength to the shortest wavelength.
- Radiowaves
- Microwaves
- Infrared
- Light wave
- Ultraviolet
- X-ray
- Gamma rays
Name all the electromagnetic spectrum from the highest frequency to the lowest frequency
- Gamma rays
- X-rays
- Ultraviolet
- Light
- Infrared
- Microwaves
- Radiowaves
What is the relationship between Energy and Wavelength?
Greater the energy, the shorter the wavelength
What happen if the microscope has reach its maximum resolution and we magnify the object more to see more detail? [2]
- We can’t be able to distingush between the two objects and not seeing any more detail.
- Image will just get more blurred as magnification increase and the resolution will not be greater.
What is the relationship between Wavelength and Frequency?
Longer the wavelength, lower their frequency.
Name all the light spectrum from the longest wavelength to the shortest wavelength.
- Red
- Orange
- Yellow
- Green
- Blue
- Indigo
- Violet
Name all the light spectrum from the highest frequency to the lowest frequency.
- Violet
- Indigo
- Blue
- Green
- Yellow
- Orange
- Red
Explain why ribosomes are not visible using a light microscope?
Because ribosome are very small that it is smaller than half of the shortest wavelength of light spectrum ( to get the best resolution in light microscope).
Why most of the time, an object must be stain when seeing it under a light microscope?
Because most of the time, the object are transparent that allow light to pass through that cause it not to be visible.
How to see an object smaller than 200 nm?
Using electron as radiation ; using electron microscope.
Why do we use electron as source of radiation when seeing an object smaller than 200 nm? [2]
- Has extremely short wavelength ( as short as X-ray)
- Has negative charge ; can be focus easily using electromagnets.
What does condenser iris diaphragm do?
Produce a narrow beam of light when slight closed
What does condenser lens do?
Focuses the light onto the specimen held by glass slide and cover slip
What does objective lens do? What magnification they have?
Collects light passing through the specimen and produce a magnified image.
Has 4x, 10x & 20x magnification
What does eyepiece lens do?
Magnifies and focuses the image from the image produce from the objective lens onto the eye.
Why shorter the wavelength, higher the resolution?
Because it diffracts less, resulting in less distrotion (more clear) in the image.
What is the function of mirror in light microscope?
It reflects light to pass through the specimen.
What is the function of stage clamps?
Hold the slide in place on the stage.
What is the function of stage clamps?
Hold the slide in place on the stage.
What is the function of arm in light microscope?
Connects to the base and supports the miroscope
What is the function of fine focus adjustor?
To focus in on details of the specimen.
What is the funtion of coarse focus adjustor?
To first focus on the specimen
What is the function of stage in light microscope?
The flat platform where you put the slide.
Why do electron have short wavelength like x-ray?
Because when electron is heated, they gain so much energy that they escape from their orbital and become free electrons.
More energy = Shorter wavelength
Why do electron microscope only can see non-living or dead specimen?
Because:
- Electron microscope needs to be vaccum to prevent the air particle to disturb the electron’s path
- Specimen need to be dehydrate bcs when the high energy electron beam is shot to the hydrated specimen, water boils at room temperature into air particle which then air particle will disturb the electron’s path.
