How Do I Solve These Wavelength and Frequency Problems?

  • Thread starter Thread starter chrish
  • Start date Start date
AI Thread Summary
The discussion focuses on solving wavelength and frequency problems related to light and radio signals. Participants emphasize the fundamental relationship between wavelength, frequency, and speed, noting that speed equals wavelength multiplied by frequency. Specific problems include calculating the wavelength of yellow light given its frequency and determining the range of wavelengths for AM and FM radio signals based on their frequencies. The conversation also touches on the tension in a string affecting wave velocity and encourages the original poster to explore their textbook for further clarification. Understanding these relationships is key to solving the presented problems effectively.
chrish
Messages
5
Reaction score
0
hey guys idk how you know all this stuff, and id appreciate if you helped me. i have to do wavelength and and frequency problems and i don't really understand how to do it the way my teacher taught it, so here they are and thanks for helping me.



1.The frequency of yellow light is 5.5 x10^14 Hz. Find the wavelength of yellow light. The speed of light is 300 000 km/s.



2.AM radio signals are broadcast at frequencies between 570 kHz and 1580 kHz (kilohertz) and travel 3.0 x10^8 m/s.

(a) What is the range of wavelengths for these signals? (Enter the wavelengths from shortest to longest.)
____m to ______ m
(b) FM frequencies range between 88 MHz and 108 MHz (megahertz) and travel at the same speed. What is the range of FM wavelengths?
______ m to _____ m


3.The velocity of a wave on a string depends on how hard the string is stretched, and on the mass per unit length of the string. If FT is the tension in the string, and µ is the mass/unit length, then the velocity, v, can be determined.
physicsq.gif

heres a pic of the formula i have to use

A piece of string 5.30 m long has a mass of 17.0 g. What must the tension in the string be to make the wavelength of a 120 Hz wave 120.0 cm?

thanks again
 
Last edited:
Physics news on Phys.org
What is the basic relationship between wavelength, frequency and speed?

Look at the units of each of those quanities, see if you figure out a way to combine them that gives you the units you need.
 
i really have no idea about any of these, they become way too confusing, i know that you can use frequency and wavelength to get speed, but that's about it
 
chrish said:
i really have no idea about any of these, they become way too confusing, i know that you can use frequency and wavelength to get speed, but that's about it
You're definitely on the right track. Now check your text to see what it says about them. Once you note that relationship (hint: it is linear expression), you can find your solutions. (Curious, what grade is this being presented?)
 
Last edited:
Speed is distance over time, yes? And wavelength is...? And the relationship between frequency and time is...? You really should be able to figure it out from there even without the book.
 
Check out the units.

Wavelength = meters
Speed of light = meters DIVIDED by seconds
Frequency = 1 DIVIDED by seconds

write these down on a piece of paper and try to figure it out from there... what are you trying to get?
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top