CBSE Class 10 Answered

First place the sample on the stage and look through the eyepiece to see if you can see the sample at all. Try moving it around slightly to get a better view. Next step is to adjust the light and focus the microscope.

The proper way to focus a microscope is to start with the lowest power objective lens first and while looking from the side, move the lens down as close to the specimen as possible without touching it.  Now slowly adjust the coarse adjustment while looking at your sample containing cells through the eyepiece. Use the coarse adjustment knob to move the objective away from the sample until it comes into focus. As you slowly turn the adjustment knob you will notice the image will get clearer and clearer. Stop adjusting when the sample is the clearest. If you can't get it in focus, repeat the process again.  Also make sure to adjust the amount of light coming through your sample.  If the light is too bright or too dark then you might not be able to see the sample very well.

Once the cells can be seen clearly with the low power lens, you should be able to simply turn in the next power lens and do minor adjustments with the focus knob.  If your microscope has a fine focus adjustment, turning it a bit should be all that's necessary.  Continue with subsequent objective lenses and fine focus each time. Make sure to begin with the microscope on the lowest magnification power. Then turn the knob up by one magnification at a time and stop to look through the eyepiece.