Tap water isn't pure. it just isn't H₂O.
Answer:

Explanation:
Area of the solar sail = A = 30 m2
Solar constant = I = 1388 W/m2
Planck's constant = h = 6.626 × 10⁻³⁴ m²kg/s
Speed of light = c = 3×10⁸ m/s
Wavelength of light =
= 570 nm
Pressure from radiation

Energy of a photon

Number of photons

Number of photons is 
Answer:
The Anatomy of a Lens
Refraction by Lenses
Image Formation Revisited
Converging Lenses - Ray Diagrams
Converging Lenses - Object-Image Relations
Diverging Lenses - Ray Diagrams
Diverging Lenses - Object-Image Relations
The Mathematics of Lenses
Ray diagrams can be used to determine the image location, size, orientation and type of image formed of objects when placed at a given location in front of a lens. The use of these diagrams was demonstrated earlier in Lesson 5 for both converging and diverging lenses. Ray diagrams provide useful information about object-image relationships, yet fail to provide the information in a quantitative form. While a ray diagram may help one determine the approximate location and size of the image, it will not provide numerical information about image distance and image size. To obtain this type of numerical information, it is necessary to use the Lens Equation and the Magnification Equation. The lens equation expresses the quantitative relationship between the object distance (do), the image distance (di), and the focal length (f)
An atom is represented by

here we know that
z = number of protons which gives an idea of positive charge of atom
A = mass number
it is the sum of number of protons and neutrons of an atom which will help us to calculate the mass of the atom
So here mass number A will give us an idea about the mass of atom
so correct answer will be
<em>A) It contains most of the mass.</em>
We know that speed is a scalar unit while velocity is a vector. The signs are mostly concerned with the magnitude that the car should travel in, the direction is not as important.
Hope I helped :)