Why you must be careful when you are focusing with the high power lens?

Why you must be careful when you are focusing with the high power lens?

Objective Lenses – The objective lens gathers light from the specimen, magnifies the image of the specimen, and projects the magnified image into the body tube. You must be very careful when using the high power lenses so you do not jam them into the slide.

How do you focus a microscope using the high power lens?

When focusing on a slide, ALWAYS start with either the 4X or 10X objective. Once you have the object in focus, then switch to the next higher power objective. Re-focus on the image and then switch to the next highest power.

When using the high power objective lens you need to be careful when adjusting the coarse adjustment knob because if you’re not careful it can?

The high power lens should be very close to your slide when in proper focus. If you turn the coarse adjustment knob while on high power, the objective could easily break your slide. NOTE: If you lose the image on high power, go back to low power and find/focus it before going up to high power again. 14.

What danger is there when switching to using the high powered lens?

If you turn the coarse adjustment under high power, you will most likely break the slide, and possibly the objective. Using the low power or scanning objective, look through the ocular and see if you can visualize the specimen.

Why does iodine and starch turn blue?

Amylose in starch is responsible for the formation of a deep blue color in the presence of iodine. The iodine molecule slips inside of the amylose coil. This makes a linear triiodide ion complex with is soluble that slips into the coil of the starch causing an intense blue-black color.

Which substance turns a blue black Colour when treated with a few drops of iodine solution?

starch substance

Why do Starch give Blue Black Colour with iodine Class 11?

Amylose present in starch is the reason for change in its colour to blue black. Iodine is not soluble in water so it is dissolved along with potassium iodide that forms a triiodide molecule which enters the helical structure of amylose and changes the colour of starch.

Why do polysaccharides gives iodine test bluish black color?

Once amylose is added, it forms another CT complex, Here, the amylose acts as a charge donor and the polyiodide as an acceptor. This complex absorbs light of a different wavelength than polyiodide, and the color turns dark blue.

Which warning about iodine is accurate?

Which warning about iodine is accurate? Iodine can stain the body and other surfaces.

What is the aim of performing iodine test?

Iodine test is a chemical test used to distinguish mono- or disaccharides from certain polysaccharides like amylase, dextrin, and glycogen. This test has a variation termed starch-iodine test that is performed to indicate the presence of glucose made by plants in the leaves.

What color is a positive iodine test?

A positive result for the iodine test (starch is present) was a colour change ranging from violet to black; a negative result (no starch) was the yellow colour of the iodine solution.

What is the principle involved in the iodine test?

Principle. The iodine test is based on the absorptive properties possessed by large polysaccharide molecules. The glucose chains in most of polysaccharides are organized to form helices. The space between the turns of the helix can hold small iodine molecules.