Answer:
n (a neutron)
Explanation:
For a chemical element:
- The lower subscript indicates the atomic number (the number of protons)
- The upper subscript indicates the mass number (the sum of protons and neutrons in the nucleus)
In the reaction described in the problem, we see that a gamma photon hits a nucleus of Calcium-40, which has
Z = 20 (20 protons)
A = 40 (40 protons+neutrons)
Which means that the number of neutrons is n = A - Z = 40 - 20 = 20
After the reaction, we have a nucleus of Calcium-39, which has
Z = 20 (20 protons)
A = 39 (39 protons+neutrons)
Which means that the number of neutrons is n = A - Z = 40 - 39 = 19
So, the nucleus has lost 1 neutron, which is the particle missing in the reaction.
C. BAT <span>can detect sound at a frequency of 67,000 Hz.
</span>
An elephant's frequency range is 16-12,000 Hz.
A tree frog's frequency range is 50 - 4,000 Hz
<span>A dog's frequency range is 67 - 45,000.</span>
Answer:
c) billions
Explanation:
there are more than 0 stars, because our sun is a star
and there are more than one because the milky way has a lot of suns
there aren't infinite because the milky way is finite it has some volume and even you made the smallest star possible you wouldn't have infinite stars
so the only option is billions
Bernoulli principle
According to Bernoulli's principle, this faster moving air on the top has a lower pressure than the non-moving air on the bottom. With a greater pressure on the bottom of the paper there is also a greater force pushing up.
There are 10⁹ picoseconds in 1 Ms
1 picosecond= 10¹² s
1 Ms = 10⁻³ s
so the number of picoseconds in one Ms=(10⁻³ s/1 Ms) * (10¹² Ps/ 1 s)=10⁹
Thus there are 10⁹ picoseconds in 1 Ms
