2. To focus a microscope using the high power lens you must first in low power center the specimen and make sure it is in focus. Then switch to high power and adjust using the fine adjustment or the smaller knob.
3. It prevents dust from settling on the scope and in the lenses.
Answer:
The answer is 6.4 × 
Joules
Explanation:
This question wants to effectively test your knowledge of the names of the negative powers of 10, so first of all, before calculating, let me explain what each of the symbols in the units given in the question means:
Force = 8.0 pN = 8.0 × 
N
displacement = 8.0 nm = 8.0 × 
N
Now let us calculate the work.
work = Force × Displacement
work = 8.0 × × 8.0 × = 64 × 
= 6.4 × 
Joules (in standard form)
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