Why do we never use oil with the 40x objective?
6. Never go back to the 10x or 40x objectives after you have applied oil to the specimen since oil can ruin the lower power objectives. [The 4x objective can be used because it is high enough to be above the oil.]
What happens if you use the oil immersion lens without oil?
Without oil, light waves reflect off the slide specimen through the glass cover slip, through the air, and into the microscope lens (see the colored figure to the right). Unless a wave comes out at a 90-degree angle, it bends when it hits a new substance, the amount of bend depending on the angle.
Why is oil necessary when using the 100x objective?
The 100x lens is immersed in a drop of oil placed on the slide in order to eliminate any air gaps and lossof light due to refraction (bending of the light) as the light passes from glass (slide) → air → glass (objective lens).
What is the significance of using oil with the immersion lens and why can’t oil be used with any other lens?
Why is it necessary to use oil in conjunction with the oil immersion lens and not with the other objectives? Because the refractive indexes of the glass microscope slide and immersion oil are the same; the oil keeps the light rays from refracting.
Can you use 100x objective without oil?
Never use the 100x objective without using immersion oil. When you have correctly brought your slide into focus up to 40x (step 3), then: a. Turn the nosepiece half-way between the 40x and 100x objectives.
What happens to the image under 100x objective if we do not put oil?
Failure to remove immersion oil from lenses will result in hardened oil on lenses that will affect future clarity. Note: Do not rotate the objective lens from 100x (oil) back to 40x (dry) before cleaning the slide. Otherwise, you will bring the immersion oil to the non-oil objective lens.
What is the purpose of the immersion oil that is used with the 100x objective quizlet?
Oil immersion should be used between the slide and 100x objective lens, this is a special oil that has the same refractive index as glass. When placed between the specimen and objective lens, the oil forms a continuous lens system that limits the loss of light due to refraction.
What happens if oil gets on a dry objective?
Dried oil is not only tough to remove from an objective lens, but this sticky substance can easily trap dust, dirt, fingerprints, and other contaminating particles. Otherwise, the technician might unknowingly contaminate samples and other objectives with the oil residue.