Answer:
B. +m
Explanation:
The magnification of an image is defined as the ratio between the size of the image and of the object:

where we have
y' = size of the image
y = size of the object
There are two possible situations:
- When m is positive, y' has same sign as y: this means that the image image is upright
- When m is negative, y' has opposite sign to y: this means that the image is upside down
Therefore, the correct option representing an upright image is
B. +m
Answer:
a) There are
electrons in a liter of water.
b) The net charge is -53601707,1 C
Explanation:
a) To find out how many electrons are in a liter of water (equivalent to 1000 grams of water), we have to find out how many molecules of water there are and then multiply it by 10 (e- per molecule).
We can find out how many molecules are by finding the number of moles and then multiplying it by Avogadro's number (number of elements per mol):

b) As all electrons have the same charge, in order to find the net charge of those electrons we have to multiply the charge of a single electron by the number of electrons:

An important clarification is that while the net charge may seem huge, water as a whole is a neutral medium, because there are as many protons as there are electrons, and as they have the same charge, the net charge of water is 0.
Answer: (Next time put the Image but I know what u talkin bout)
wave changes its path from its initial direction so this phenomenon is known as Refraction of wave
Explanation:
When wave travels from one medium to other medium the due to change in the speed of the wave propagation it deviates from its initial path.
The deviation of the wave from its initial path is known as refraction of wave
Here we can see that wave incident on medium 1 with some angle with the boundary
Then it enters into other medium and then travels in other direction
So here wave changes its path from its initial direction so this phenomenon is known as Refraction of wave