The heat (energy) needed to raise the temperature of the water is given by

The wavelength of the radiation of the oven is

, so the energy of a single photon of this radiation is

So, the number of photons required to heat the water is the total energy absorbed by the water divided by the energy of a single photon:

photons
Answer:
The correct answer is option A: they are isotopes.
Explanation:
From atom X we know that the number of protons is 7 and the number of neutrons is 7 and from atom Z we know that the number of protons is 7 and the number of neutrons is 8.
Since the number of protons of atom X and atom Z is the same, we have that atom X and atom Z is the same element. The difference in the number of neutrons tells us that atom X and atom Z are isotopes. Remember that an isotope is one element that has atoms with different numbers of neutrons.
The mass number is given by:
Where <em>n</em> is the number of neutrons and <em>p </em>is the number of protons.
For atom X and atom Z we have:

Hence, they have a different mass number.
We know that the element with 7 protons is nitrogen. The first isotope is
and the second isotope is
. Both isotopes are stables (they are not radioactive).
Therefore, the correct answer is option A: they are isotopes.
I hope it helps you!
Answer:
B splits and goes through two components
Explanation:
- A series circuit is a circuit in which the components are all connected along the same branch: as a result, the current flowing through the components is the same, while the sum of the potential differences across each component is equal to the emf of the battery
- A parallel circuit is a circuit consisting of separate branches, so that each branch has a potential difference equal to the emf of the battery. As a result, in such a circuit the current in the circuit splits and goes through the different branches/components.
So, the correct answer is
B splits and goes through two components
Answer:
A. Na2S + 2KCI - 2NaCl + KZS
Explanation: