Answer:
Maximum Power = 144.3 D
The associated focal length of the lens = 
Explanation:
According to the Lens maker's Formula:

where;
= the refractive index of the medium
and
= radius of curvature on each surface
For a convex lens, The radius of curvature in the front surface will be positive and that of the second surface will be negative . Therefore;

At maximum power

= 
This Implies

Therefore; the power is given by the formula:


= 144.3 D
It rises because hot air is less dense than cool air.
Answer:
D. Solar Eclipse
Explanation:
This is quite a phenomenal occurrence. Please, allow me to explain why D is correct.
A. A New Moon: This is the moon's first lunar phase. This is such a phase during which the sun and earth are located at nearly precise opposite ends of the moon, an occurrence that renders the moon nearly (if not) entirely invisible by the naked eye from an earthly perspective. This is not an occurrence that renders darkness during daylight.
B & C: (Partial & Total) Lunar Eclipse: A Lunar Eclipse is a beautiful occurrence that is visible <em>only </em>during nightfall, but can be witnessed from any location on earth that is <em>currently facing away from the sun </em>(a.k.a. nighttime hours). This occurs when the earth, sun, and moon are nearly perfectly aligned, with the sun and moon at opposite ends of the earth. The earth blocks the light of the sun, and though the side <em>facing </em>the sun won't experience any difference, the side <em>facing away from the sun </em>will be able to see the light from the sun beam around the earth, hitting the moon and reflecting back on us. The shadow of the earth entirely covers the moon during this event. The phases determines exactly what we see and to what degree/extent. This eclipse itself can happen numerous times a year, though only in Partial or Penumbral phases.
D. A Solar Eclipse: A solar eclipse is a breathtaking and oftentimes somewhat terrifying occurrence during which the moon passes <em>perfectly </em>in between the earth and the sun. Unlike a New Moon, however, this occurrence is perceived <em>during the day</em>, so for the side of the earth FACING the sun. When the moon is making its journey in between the sun and earth (which takes roughly 3-5m), the massive silhouette of the moon can be seen blotting out the sun, effectively causing a brief moment of darkness during daytime hours. This occurence is considered remarkably rare because DESPITE it occuring once per year, it can ONLY be viewed from specific locations on earth.
Qualitative data is easy to explain. You either agree or disagree in writing. Wrong. You agree, disagree, or qualify. Meaning agree to somewhat extend, but not entirely. So you can agree that people should walk instead of talk in the progressive manner, but not in the impulsive manner.
They are positive and remain inside the nucleus.