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
two particles with the positron emission mechanism.
I think B or D because an eye obviously doesn't have a lense, mirror..maybe sorry for not giving u straight forward response
Answer:
The melting point of a substance is the temperature at which it change state from solid to liquid is called crystallization point.
Answer:

Given:
Mass = 14.0 g
Density (
) = 1.38 g/cm³
To Find:
Volume (V)of the plastic used to make water bottle
Explanation:
Formula:

Substituting value of m & density in the formula:


Volume of the plastic used to make water bottle = 10.14 cm³
<span>Out of the possible answers for this question, fluorine in the second period is correct. Of the four elements fluorine, chlorine, bromine and iodine, fluorine has the largest first ionization energy, with a Enthalpy number of 1681.0. Of all the elements, helium has the highest first ionization energy figure.</span>