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Structure Of Atom

Question
CBSEENCH11005236
Wired Faculty App

Calculate the frequency and wavelength of light of wavelength:
(i) 5000 A   (ii) 4.4 mμ      (iii) 580 mm

Solution

(i) Wavelength of light, 
straight lambda space equals space 5000 space straight Å space equals space 5000 space cross times space 10 to the power of negative 10 end exponent straight m
Velocity of light, straight c equals 3 cross times 10 to the power of negative 8 end exponent ms to the power of negative 1 end exponent
therefore space space space straight v space equals space straight c over straight lambda space equals space fraction numerator 3 space cross times space 10 to the power of 8 space ms to the power of negative 1 end exponent over denominator 5000 space cross times space 10 to the power of negative 10 end exponent straight m end fraction space equals space 6 cross times 10 to the power of 14 straight s to the power of negative 1 end exponent space space space space space space space space equals 6 cross times 10 to the power of 14 Hz.
Wave number,
straight v with bar on top space equals space 1 over straight lambda space equals space fraction numerator 1 over denominator 5000 space cross times space 10 to the power of negative 8 end exponent cm end fraction space equals 2 space cross times 10 to the power of 4 cm to the power of negative 1 end exponent
(ii) Wavelength of light,
             straight lambda space equals 4.4 space mμ space equals space 4.4 space cross times space 10 to the power of negative 6 end exponent straight m space left square bracket because space 1 space mμ space equals space 10 to the power of negative 6 end exponent straight m right square bracket
Velocity of light c = 3 x 108 ms-1
because space space straight v space equals space straight c over straight lambda space equals fraction numerator 3 space cross times space 10 to the power of 8 space ms to the power of negative 1 end exponent over denominator 4.4 space cross times space 10 to the power of negative 6 end exponent straight m end fraction space equals space 6.8 space cross times space 10 to the power of 13 straight s to the power of negative 1 end exponent space space space space space space space equals space 6.8 space cross times space 10 to the power of 13 Hz Wave space number comma space straight v with bar on top space equals space 1 over straight lambda space equals space fraction numerator 1 over denominator 4.4 space cross times space 10 to the power of negative 6 end exponent space cross times space 10 to the power of negative 6 end exponent space cross times space 10 squared space cm end fraction space equals space 2.27 space cross times space 10 cubed space cm to the power of negative 1 end exponent

(iii) Wavelength of light, straight lambda = 580 nm
                                       = 580 x 10-9m
Velocity of light, c = 3 x 108 ms-1
therefore space space space straight v space equals space straight c over straight lambda space equals space fraction numerator 3 space cross times space 10 to the power of 8 ms to the power of negative 1 end exponent over denominator 580 space cross times space 10 to the power of negative 9 end exponent straight m end fraction space equals space 5.17 space cross times space 10 to the power of 14 straight s to the power of negative 1 end exponent space space space space space equals 5.17 space cross times space 10 to the power of 14 Hz Wave space number comma straight v with bar on top space equals space 1 over straight lambda space equals space fraction numerator 1 over denominator 580 space cross times space 10 to the power of negative 7 end exponent space cm end fraction space equals space 1.72 space cross times space 10 to the power of 4 space cm to the power of negative 1 end exponent

Some More Questions From Structure of Atom Chapter

Name the particles which determine the mass of an element.

What are α-particles?

Why were neutrons discovered very late?

What are the fundamental particles present in a neutral atom having atomic number greater than 1?

Do protons and neutrons have identical mass?

When α-particles are sent through a thin metal foil, most of them go straight through the foil. What inference do you draw from it?

What did Rutherford's experiment on scattering of particles show for the first time?

What is Plum-Pudding model of the atom?

Are neutrons present in all atoms?

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