Answer:
Explanation:
Threshold frequency = 4.17 x 10¹⁴ Hz .
minimum energy required = hν where h is plank's constant and ν is frequency .
E = 6.6 x 10⁻³⁴ x 4.17 x 10¹⁴
= 27.52 x 10⁻²⁰ J .
wavelength of radiation falling = 245 x 10⁻⁹ m
Energy of this radiation = hc / λ
c is velocity of light and λ is wavelength of radiation .
= 6.6 x 10⁻³⁴ x 3 x 10⁸ / 245 x 10⁻⁹
= .08081 x 10⁻¹⁷ J
= 80.81 x 10⁻²⁰ J
kinetic energy of electrons ejected = energy of falling radiation - threshold energy
= 80.81 x 10⁻²⁰ - 27.52 x 10⁻²⁰
= 53.29 x 10⁻²⁰ J .
Almost all of the energy on Earth comes from the Sun
The energy in fossil fuels originally came from the Sun
Plants convert the energy
Explanation:
The sun is the ultimate source of energy on earth and even the whole of the solar system. The sun drives and powers all external processes on earth. It produces its energy from the nuclear fusion of lighter nuclei into heavier ones.
- Almost all of the energy on earth comes from the sun. A few component of the energy on the surface comes from the internal heat engine.
- The energy of fossil fuels originally came from the sun. This is because, plants stores the energy in the process of photosynthesis. When they die and the energy is not released, the energy is stored as fossil fuels.
- Plants in the process of photosynthesis converts the energy. Here green plants combines carbon dioxide and water in the presence of sunlight.
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Answer:
0.0928km/min (4dp)
Explanation:
To find the jogger's speed in km per minute, we just need to divide the number of km jogged by the time in minutes it took to jog that distance. This will give us the distance they jogged every minute which is their speed.
4km in 32 minutes:
4/32 = 0.125km/min
2km in 22 minutes:
2/22 = 0.091 (3dp)km/min
1km in 16 minutes:
0.0625km/min
Now to find the average speed of these 3 speeds, we just add them all together and divide by how many values there are (3 values).
Average (mean) = 
Average = 0.2785/3
Average speed of jogger = 0.0928 (4dp) km/min
Hope this helped!
Explanation:
Kinetic Energy Formula = ½mv²
- ½×800kg×(23m/s)²
- 400kg×529m²/s²
- 211600 kg•m²/s²
- 211700 joule Answer
Answer:
active solar heating systems use solar energy to heat a fluid either liquid or air and then transfer the solar heat directly to the interior space or to a storage system for later use. If the solar system cannot provide adequate space heating, an auxiliary or back-up system provides the additional heat.
hope this helps : )
