Question

your field of view measured at 400 x is 0.45 mm. what is your field of view at 40x in nm? Scientific notation

Answer 1

First of all we must know what field of view is, Field of view is actually the extent (or diameter) of observable area which is visible at a time through the microscope.

This field of view differs for different magnification under which we are observing.

Scientific Notation and explanation of field of view at various magnifications:

We know that basically a compound microscope has 10x magnification ocular (eyepiece) and 4 objective lenses of various magnifications (4x, 10x, 40x &100x). So, total magnification in case of each objective used is different and is calculated by simply multiplying the ocular magnification with the objective magnification. For example, total magnification if 40x objective is used= 10x X 40x = 400x.

Now, question arises how field of view is calculated? -Actually it is found experimentally using a stage micrometer. A stage micrometer is simply a slide with microscopic scale divisions( in mm). For each magnification, the field of view is measured by measuring the diameter of observable area.( Just like we measure the diameter of a circle with a big scale). The final measurements are found to be:

1. At 40x magnification = 4.45mm

2. At 100x magnification= 1.78mm

3. At 400x magnification = 0.45mm

4. At 1000x magnification = 0.178mm

To answer your question, you have to just convert the value of of field of view at 40x in mm to nm. You should know how to convert it:

1mm= 1000000 nm

So, 4.45mm = 4.45 X 1000000 = 4450000 nm.

The above is scientific Notation. But there is also a simple formula for finding field of view at a magnification if field of view at another magnification is given. The value which comes by formula is approximate value and may not accurately match the actual value which was found out experimentally.The formula is:

F.o.v at 2 = F.o.v at 1 X magnification of given divided by magnification of 2.

Using this formula you can easily find out :

F.o.v at 40x = 0.45 X 400 divided by 40

This comes to be 4.5mm = 4500000nm (approximate value, precise value was the one which was found out experimentally.)

Hope your answer is clear. Thanks.