![subject](/tpl/images/cats/geografiya.png)
Geography, 28.09.2019 23:30 anamatiascamaja
The mass of the sun is 2*10^30 kg. it currently consists to about 70% (mass) of hydrogen. the dominant source of energy for the sun is the pp-chain (type i) fusion process in which four protons fuse into a 4he core consisting of two protons and two neutrons. this process releases 26.22 mev ( = 4.2*10^-12 j) of energy. assume that to first order the luminosity of the sun remains constant at 1.1 times its current-day value. how long will it take for the sun until the fraction of hydrogen is reduced from 70% to 30%?
![ansver](/tpl/images/cats/User.png)
Answers: 1
Another question on Geography
![question](/tpl/images/cats/geografiya.png)
Geography, 22.06.2019 17:00
The specific heat of the three substances in the image are given in the table. stamped concrete: 0.75, grass covered soil: 1.01, water: 4.18. place the areas in order based on how fast they’ll heat up on a sunny afternoon. start with the fastest and end with the slowest.
Answers: 1
![question](/tpl/images/cats/geografiya.png)
Geography, 22.06.2019 20:00
Brian's school locker has a three-digit combination lock that can be set using the numbers 5 to 9 (including 5 and 9), without repeating a number. the probability that the locker code begins with a prime number is %. the probability that the last digit of the locker code is an odd number is %.
Answers: 1
![question](/tpl/images/cats/geografiya.png)
Geography, 23.06.2019 03:10
Wegeners theory of continental drift states that the continents have changed throughout history while the theory of plate tectonics
Answers: 1
![question](/tpl/images/cats/geografiya.png)
Geography, 23.06.2019 13:00
Where was oil production at its highest in the 1980s and still remains important to the russian economy? central asia the ural mountains russian siberia the caucasus region
Answers: 2
You know the right answer?
The mass of the sun is 2*10^30 kg. it currently consists to about 70% (mass) of hydrogen. the domina...
Questions
![question](/tpl/images/cats/biologiya.png)
Biology, 16.12.2020 14:00
![question](/tpl/images/cats/istoriya.png)
History, 16.12.2020 14:00
![question](/tpl/images/cats/fizika.png)
![question](/tpl/images/cats/istoriya.png)
![question](/tpl/images/cats/fizika.png)
![question](/tpl/images/cats/himiya.png)
Chemistry, 16.12.2020 14:00
![question](/tpl/images/cats/en.png)
![question](/tpl/images/cats/obshestvoznanie.png)
Social Studies, 16.12.2020 14:00
![question](/tpl/images/cats/mat.png)
![question](/tpl/images/cats/istoriya.png)
History, 16.12.2020 14:00
![question](/tpl/images/cats/es.png)
Spanish, 16.12.2020 14:00
![question](/tpl/images/cats/mat.png)
Mathematics, 16.12.2020 14:00
![question](/tpl/images/cats/mat.png)
Mathematics, 16.12.2020 14:00
![question](/tpl/images/cats/mat.png)
![question](/tpl/images/cats/en.png)
![question](/tpl/images/cats/ekonomika.png)
![question](/tpl/images/cats/en.png)
![question](/tpl/images/cats/mat.png)
Mathematics, 16.12.2020 14:00
![question](/tpl/images/cats/biologiya.png)