All Leaving Cert Biology posts
• #### How do answer this Biology question? michaels

Lens E is marked 10× and lens O is marked 40×.

A cell is viewed through lenses E and O.

The image of the cell is 0.8 mm in diameter.

What is the actual diameter of the cell?

1. #### Moriarty

Total magnification of 400x which means that the image you are seeing is 400 times the actual size. This "magnified" image is 0.8mm so the "original/actual" image must be 400 times smaller than this (0.8mm/400).

2. #### Niamhoc22

because you are looking through both lenses the total magnification is 400 (10x40). At magnification 400 the cell has a diameter of 0.8mm, so to find what the diameter is with no magnification you must divide 0.8 by 400. :)

3. #### what.the.matter.is.the

To find the magnification of a cell you multiply the lens powers, here it is 10x and 40x. Therefor, the final magnification will be 400x ( See x as magnified 400 times).

Now 400times of an object makes it 0.8mm in diameter.

That is,

400y = 0.8;

y = 0.8/400

y = 0.002mm