Answer:
atoms
Explanation:
All matter is made of elementary particles called "atoms".
Stars form from an accumulation of gas and dust, which collapses due to gravity and starts to form stars. The process of star formation takes around a million years from the time the initial gas cloud starts to collapse until the star is created and shines like the sun
Answer:
a

b

Explanation:
From the question we are told that
The wavelength is 
The energy is 
This energy is mathematically represented as

Where c is the speed of light with a value 
h is the Planck's constant with the value 
n is the number of pulses
So

substituting values


Given that the pulses where emitted 20 times in one second then the period of the pulse is


Hence the average power of photons in one 80-mJ pulse during 1 s is mathematically represented as

substituting values


Answer:
1) λ = 24.7 cm, 2) f = 13.88 Hz, 3) L = 117.3 cm
Explanation:
1) This is a resonance process, that is, the wave going downwards will interfere with the wave going upwards.
This is a tube with one end closed and the other open, at the closed end there is a node and at the open end a belly, so the resonances are
L = λ / 4
λ = 4L 1st harmonic
λ = 4L / 3 third harmonic
λ = 4L / 5 fifth harmonic
λ = 4L / n ’ n’ odd number n ’= (2n +1)
the wavelength is requested for the eighth resonance n = 8, the corresponding prime number is
n ’= 2 8 +1
n ’= 17
we substitute
λ = 4 105/17
λ = 24.7 cm
2) the speed of the wave is related to the wavelength and frequency
v = λf
f = v /λ
f = 343 / 24.7
f = 13.88 Hz
3) the next resonance occurs for n = 9, so the prime number is
n ’= 2 9 +1
n ’= 19
L = n’ λ / 4
L = 19 λ / 4
We must suppose a value for the wavelength, if the wavelength is present in the tube and the length of the column increases, the resonance number increases
L = 19 24.7/4
L = 117.3 cm