What is the wavelength of the helium-neon laser beam in the unknown liquid?

  • Thread starter Thread starter allstar16
  • Start date Start date
  • Tags Tags
    Laser Wavelength
AI Thread Summary
The wavelength of a helium-neon laser beam in air is 633nm, and it takes 1.38 ns for the beam to travel through 30cm of an unknown liquid. To find the wavelength in the liquid, the index of refraction can be calculated using the formula n=c/v, where c is the speed of light and v is the speed of light in the liquid. The time and distance provided allow for the calculation of the speed of light in the liquid. Once the index of refraction is determined, the wavelength in the liquid can be found by dividing the wavelength in air by the index of refraction. This approach provides a clear path to solving the problem without needing additional information.
allstar16
Messages
2
Reaction score
0
A helium-neon laser beam has a wavelength in air of 633nm. It takes 1.38 ns for the light to travel through 30cm of an unknown liquid.
What is the wavelength of the laser beam in the liquid?
 
Physics news on Phys.org
How do you think you might be able to solve this? What are your thoughts?
 
First i thought to solve for the index of refraction for the unknown liquid, by using n=c/v, but i think i need more info to solve it, that's were I am stuck
 
You shouldn't need any more information. Look at what you are given. You have a time to travel a certain distance. What can you find with this information?
 
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
Back
Top