Positron emission = emission of a positron and a neutrino when a proton is convert into a neutron. The total number of particles in the nucleus doesn't change, -1 proton +1 neutron
It's a spontaneous reaction for some nucleus.
eg:
Positron = e+
Neutrino=ve
O-15 --> N-15 + e+ +ve
Electron capture= A nucleus absorb an electron while a proton is convert in a neutron and emit a neutrino. The total number of particles in the nucleus doesn't change, -1 proton +1 neutron
eg:
Al-26 +e- --> Mg-26 + ve
Electron capture and positron emission are two mechanisms to explain the decay of some unstable isotopes. Electron capture is usually observed when the energy difference between the initial and final state is low. Mainly because of the larger amount of kinetic energy need for the expulsion of two particles with the positron emission mechanism.
Answer:
i dont know thank you soo much
Answer:
d. 26.0 km
Explanation:
If the temperature in the region increases with depth by about 25 °C /km, then at a depth of 2 km the temperature would be 50 °C higher, at a depth of 3 km the temperature would be 75 °C higher and so on.
<u>The only way for finding melted quartz would be if the temperature is at least 650 °C.</u>
- Temperature = 25 °C /km * Depth
We put the data given by the problem and <u>solve for Depth</u>:
- 650 °C = 25 °C /km * Depth
For a reaction system at equilibrium, LeChatelier's principle can be used to predict the "effect of a stress on the system".
<u>Option: C</u>
<u>Explanation:</u>
Le Chatelier's theory can be implemented to forecast a system's behavior due to variations in pressure, temperature, or concentration that will lead in predictable and contested variations in the system adjustments to establish a new state of equilibrium. This means that adding heat to a process would favor the endothermic path of a reaction, because this decreases the amount of heat generated in the system.
Here shift in equilibrium take place when volume increase, the total pressure decreases, which have potential to reverse the reaction, while on increasing pressure of system, the total volume decreases of the gaseous system, which can shift an equilibrium in the direction of the fewer molecules.
