help on electric current please?

Question

1) If the wavelength of light changes as light goes from one medium to another, while the frequency remains the same. If the wavelength is shorter in water than in air, than the following:

a) A certain blue-green light has a wavelength of 600 nm (6x10^-7 m) in air. What is its wavelength in water, where light travels at 75% of its speed in air? __nm

b)What is its wavelength in Plexiglas, where light travels at 67% of its speed in air?__nm

Answer 1

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Refractive index of medium =n=velocity of light in vacuum(c) /velocity of light in medium(v)

velocity of light in vacuum(c) =frequency(f)*wavelength in vacuum(Lo)

c=f*Lo

velocity of light in medium(c) =frequency(f)*wavelength in medium(Lm)

v=f*Lm

Dividing, c by v,

c /v =Lo /Lm

Refractive index of medium =n =c/v=Lo/Lm

Refractive index of medium =n =Lo/Lm

Refractive index of water=nw=velocity of light in vacuum(c) /velocity of light in water(v)

Refractive index of water=nw=wavelength in vacuum (Lo)/wavelebgth in water(Lw)

Refractive index of water=nw=(Lo)/(Lw)

wavelength in water(Lw)=Lo/nw

wavelength in water(Lw)= 6x10^-7/(4/3) =4.5*10^-7 m

(a)wavelength in water (Lw) = 450 nm
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wavelength in Plexiglas, where light travels at 67% of its speed in air= wavelength in air /Refractive index of Plexigas=Lo /(c/v)


wavelength in Plexiglas = wavelength in air /Refractive index of Plexigas=Lo /(c/v)

wavelength in Plexiglas =[6x10^-7/(100/67)

wavelength in Plexiglas, =4.02x10^-7m

(b) wavelength in Plexiglas, where light travels at 67% of its speed in air is 402 nm
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Answer 2

the speed at which light travels never changes. Only the frequency or intensity. that's is what causes the difference in water and in air.
450 nm
390 nm

Answer 3

Wavelength and frequency are interdependent variables in very basic physics. Check your basic premise for the question and re-qualify it.

Answer 4

450 nm; 400 nm.