Answer:
Bohr used emission spectrum for its mono atomic model....
Explanation:
Emission Spectrum is produced when atoms are excited by energy. After excitation, they emit this energy in the form of different wavelengths according to the type of atom and produce a unique fingerprint of themselves called as it's emission spectrum.
Absorption Spectrum is a type of spectrum that is produces when photons of light are absorbed by electrons at one state. they jump to another state and may cause scattering. This produces a specific absorption spectrum for that specific atom.
Answer : The amount of formaldehyde permissible are, 
Explanation : Given,
Density of air = 
First we have to calculate the mass of air.
Now we have to calculate the amount of formaldehyde.
Permissible exposure level of formaldehyde = 0.75 ppm = 
Amount of formaldehyde in 7.2 g of formaldehyde = 
Amount of formaldehyde in 7.2 g of formaldehyde =
Thus, the amount of formaldehyde permissible are,
Contains only Carbon and Hydrogen.
(3) CH3CH3
Answer:
1.- The energy of a wave will increase the frequency due to the increase in the speed of the wave.
2.- The wavelength will increase if the energy of the wave increases, due to the area that is expand.
3.- A wave with a higher frequency will have faster speed to move.
Explanation:
Wavelength of a wave is due to the speed and the energy that the wavelength carry, so if the energy increases, this quantity of energy need to distribute or in the wavelength or in the frequency, to conduct the wave with a bigger amount of energy.
The elements are identified by the number of protons of the atom, which is its atomic number.
In this case the number of protons 39 (atomic number 39) permit you to identify the element as gallium.
Now, to identify the isotope you tell the name of the element and add the mass number.
The mass number is the sum of the protons and the neutrons
In this case, the number of neutrons is the original 39 plus the 2 added suddenly, i.e. 39 + 2 = 41, so the mass number is 31 + 41 = 72
Therefore, the isotope is gallium - 72.
Answer: isotope gallium - 72
