The relationship between the number of visible spectral lines are identical for atoms .However they have unique wavelengths.
Option B
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Explanation:</u>
A spectrum is a range of frequencies or a range of wavelengths. The photon energy of the emitted photon is equal to the difference between two states. For every atom there are quite many electron transitions and each has a energy difference.
This difference in wavelength causes spectrum .As each element emission spectrum is unique because each atom has different energy and causes uniqueness in the emission spectrum . Hence, due to the difference in energy it emits different wavelengths.
Answer:
The values is 
Explanation:
From the question we are told that
The speed of the fire engine is 
The frequency of the tone is 
The speed of sound in air is 
The beat frequency is mathematically represented as

Where
is the frequency of sound heard by the people in the fire engine and is is mathematically evaluated as
![f_a = [\frac{v_s + v }{v_s -v} ]* f](https://tex.z-dn.net/?f=f_a%20%20%3D%20%20%5B%5Cfrac%7Bv_s%20%2B%20v%20%7D%7Bv_s%20%20-v%7D%20%5D%2A%20f)
substituting values
![f_a = [\frac{340 + 5 }{340 -5} ]* 500](https://tex.z-dn.net/?f=f_a%20%20%3D%20%20%5B%5Cfrac%7B340%20%2B%205%20%7D%7B340%20%20-5%7D%20%5D%2A%20500)

Thus


Answer:
For the first one c is the answer
For the second one c is also the answer
For the third one is b
Explanation:
I took that
Dude it’s 8.1 Km. Bet it’s right.