One simple way to losing weight is by calorie counting. Peter can go to his nutritionist and learn just how much calories he can have as intake per day to lose weight. The nutrition label on any food item lists the calories and their serving sizes. This can be used to keep track of how much calories Peter has taken each day, so as to not go over his daily limit.
Answer:
The near point of an eye with power of +2 dopters, u' = - 50 cm
Given:
Power of a contact lens, P = +2.0 diopters
Solution:
To calculate the near point, we need to find the focal length of the lens which is given by:
Power, P = 
where
f = focal length
Thus
f = 
f =
= + 0.5 m
The near point of the eye is the point distant such that the image formed at this point can be seen clearly by the eye.
Now, by using lens maker formula:

where
u = object distance = 25 cm = 0.25 m = near point of a normal eye
u' = image distance
Now,



Solving the above eqn, we get:
u' = - 0.5 m = - 50 cm
Photovoltaic cells are the most efficient means of converting solar energy to electricity. Option b is correct.
<h3>What is a cell?</h3>
A cell is a voltage and current-producing device that consists of a single anode and cathode separated by an electrolyte.
One or more cells can make up a battery. One cell, for example, is one AA battery.
Light intensity on a solar cell is often measured in "suns," with one sun roughly equivalent to 1 kW/m².
Concentrated sunlight improves the ratio of current generated while the device is lighted vs when it is dark, hence enhancing output voltage and efficiency.
Photovoltaic cells are the most efficient means of converting solar energy to electricity.
Hence, option b is correct.
To learn more about the cell refer to:
brainly.com/question/3142913
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Answer:
<em>The magnitude of the force is 10 N</em>
Explanation:
<u>Coulomb's Law</u>
The electrostatic force between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between the two objects.
Written as a formula:

Where:

q1, q2 = the objects' charge
d= The distance between the objects
We have two identical charges of q1=q2=1 c separated by d=30000 m, thus the magnitude of the force is:


F = 10 N
The magnitude of the force is 10 N
Answer:
Light waves slow down as they travel from gas to solid.
Explanation:
The speed of light is often quoted with reference to a vacuum. Light travels fastest in a vacuum and in a gas.
When light travels through other media such as solids or liquids, the speed of light is decreased due to absorption and scattering of photons by molecules as well as remissions.
Hence the speed of light decreases from gas to solid.