(a)    
(i) The coarse focus wheel adjusts the objective lens roughly.

(ii)
Magnification is 10 x 40 = 400
Diameter = 0.8mm under microscope
               = 0.8/400 = 0.002mm

(b)    
(i) Rinse your mouth with water. Using a clean spatula, gently scrape along the inside of your cheek. Spread the cells on a clean glass slide.

(ii) Methylene blue

(iii) Place one end of the coverslip down at an angle. Then using a mounted needle, gently lower the other end, forcing the air bubbles out as the cover is lowered.

 


(iv) A coverslip is used to protect the specimen.

(v)

1. Place the slide on the stage.
2. Using the coarse adjustment, bring the lowest power lens as close as possible to the slide without touching.
3. Then while looking in the eyepiece lens, use the coarse focus knob to raise the objective lens and bring the slide into focus.
4. Once in focus you can use the fine focus knob to sharpen the image.
5. Change the objective lens and use the fine focus adjustment to get the best picture.

(vi)