We have that the time in seconds, minutes, and hours is



From the Question we are told that
Velocity 
Distance 
Generally the equation for the Time is mathematically given as
Therefore


And


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Parfocal is the term used to describe a microscope that maintains focus when the objective lenses are replaced.
<h3>
What is the name of the objective lens ?</h3>
For observing minute features within a specimen sample, a high-powered objective lens, often known as a "high dry" lens, is perfect. You can see a very detailed image of the specimen on your slide thanks to the 400x total magnification that a high-power objective lens and a 10x eyepiece provide.
The four objective lenses on your microscope are for scanning (4x), low (10x), high (40x), and oil immersion (100x).
The first-stage lens used to create a picture from electrons leaving the specimen is referred to as the "objective lens." The objective lens is the most crucial component of the imaging system since the quality of the images is determined by how well it performs (resolution, contrast, etc.,).
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Try B if it is not it I am sorry I checked on Google
They are moving in opposite direction, cant find out anything else because not enough informations is provided, like time .
Answer:
(a) q=3.07 nC
(b) σ=17 nC/m²
Explanation:
Given data
Radius r=0.12m
Potential V=230 V
To find
(a) Charge q
(b) Charge density σ
Solution
For Part (a)
As we know that potential is:

Substitute the given values

For Part (b)
The charge density is given by:
σ=q/(4πr²)
Substitute the given values and value of q to find charge density
So

σ=17 nC/m²