The answer is A.
Hydroelectric, which is usually generating electricity through use of a dam.
Solar, energy from the Sun.
Biomass, organic material formed from plant matter.

9. An object which is in circular motion (moving along a circle) is said to be accelerating because it changes it's direction constantly even if it is moving with a constant speed. cuz acceleration is change in either magnitude or direction of an object with respect to time.
therefore, it's still acceleration as change in direction with time.
10. Average speed of an object can be calculated by dividing the total distance covered by an object by time taken to cover that distance.
i.e
it can be re- arranged to find the distance as :
11. speed = 20 m/s : conversion into km/h
distance covered : 4 km = 4000 m
time taken = 200 seconds
12. let's use the first equation of motion to find the acceleration :
Answer:
because of the idea that like charges get repulsion as a force.
Explanation:
because you wrap the ball with foil, the negative charges will leave the foil and go into the ball by induction. This leaves the foil as a positively charged particle since its electrons left it for the ball, making the ball a negatively charged particle. but if you bring the negative charge near the foil, the electrons will transfer from that and go into the foil, making it negatively charged. Now, because the ball and the foil have the same charge, they repel. the foil flies off.
The elements in NaCl are Na -sodium and Cl - chlorine
<u>Explanation:</u>
- sodium chloride (NaCl) is also known as common salt. The molar ratio of NaCl is 1:1 and has the molar mass of 22.99 and 35.45 respectively. The molar mass of NaCl is 58.443 g/mol. It is a odorless and colourless cubic crystal.
- It has the melting point of 800.7°C and has the boiling point of 1465°C. It has a face centered cubic crystal structure.The elements in NaCl are Na -sodium and Cl - chlorine
→ 
(a) 
The energy of a photon is given by:

where
is the Planck constant
is the speed of light
is the wavelength
For the microwave photon,

So the energy is

And converting into electronvolts,

(b) 
For the energy of the photon, we can use the same formula:

For the visible light photon,

So the energy is

And converting into electronvolts,

(c) 
For the energy of the photon, we can use the same formula:

For the x-ray photon,

So the energy is

And converting into electronvolts,
