Answer:
A. They have the same atomic numbers.
Explanation:
Elements are defined based on the atomic number, which is the number of protons in the nucleus: this means that atoms of the same element have always the same number of protons in their nuclei (and so, always the same atomic number).
The other choices are wrong because:
B. They have the same average atomic masses. --> this is false for isotopes, which are atoms of the same element having a different number of neutrons. Since the atomic mass is calculated from the sum of the masses of protons and neutrons in the nucleus, two isotopes of the same element have different atomic mass
C. They have the same number of electron shells. --> this can be false when an atom of an element loses/gains an electron, becoming an ion: in that case, the number of electron shells can change, since the number of electrons has changed.
D. They have the same number of electrons in their outermost shells. --> this is also false in case one of the atoms is an ion, since the number of electrons is different.
Answer:
Interference
Explanation:
When two waves of same frequency and constant phase difference super impose at a point on the screen then due to their superposition we will get different intensity of light at different positions of the screen
This phenomenon of redistribution of energy is known as interference of light.
So at the position of screen where the light intensity is maximum on the screen is known as constructive interference while the positions on the screen where it will get minimum intensity on the screen is known as destructive interference of the light
So correct answer would be
Interference
