How can I solve these two challenging AS physics questions?

  • Context: High School 
  • Thread starter Thread starter meawinner
  • Start date Start date
  • Tags Tags
    Hard Physics
Click For Summary

Discussion Overview

The discussion revolves around two challenging AS physics questions related to photon production and properties. The first question involves calculating the number of visible photons emitted per second from a 2 Watt lamp, given a specific wavelength. The second question concerns the time of travel for a photon and the number of rotations of its phasor over a specified distance.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant, meawinner, attempts to calculate the number of photons produced by a 2 Watt lamp but arrives at an incorrect answer, expressing confusion about the process.
  • Another participant suggests using Planck's constant and the relationship between energy and frequency to find the energy of each photon.
  • Meawinner confirms using the formula E=hf but indicates that their calculations did not match the textbook answer, leading to further uncertainty.
  • A later reply encourages meawinner to convert the given wavelength into frequency using the wave equation before applying E=hf.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct method to solve the problems, and there remains uncertainty regarding the calculations and the correct approach to take.

Contextual Notes

Participants express confusion over the calculations and the relationship between power, energy, and photon frequency. There are unresolved steps in the mathematical reasoning, particularly in converting wavelength to frequency.

meawinner
Messages
11
Reaction score
0
Here are two questions I am stuck on:
1. How many visible photons are produced per second from a 2Watt lamp? It says the range of the wavelengths is near 5x10^-7m. I tried this and got 3.33x10^33Hz but apparently that's wrong so please help me.

2. A photon of frequency 6x10^14Hz explores a path 6m long. Find the time of travel and the number of rotations of the phasor. This one I don't have a clu how to start but if I get the first answer I can easily work out the number of rotations of the phasor.

Please help me as I am really stuck...physics is really hard on this AS course. Thanks for all your help

meawinner
 
Physics news on Phys.org
Mea, do you know the energy of each photon is given by Planck's constant times the frequency?

2 Watts is power = energy per second.
 
Yup

Yeah i tried this and that's where i got the 3.33blah blah blah... answer. I used 2W = 2joules per second and therefore if its one second it 2 joules, i put this in E=hf and it came out wrong as that's not the answer in my textbook. Dont say why can't i just copy it because the teacher will know if there is no working. But thanks anyway. Do you know any other way?
 


Originally posted by meawinner
... Do you know any other way?
Try again. First find the energy of a single photon, using E =hf. (Hint: First change the given wavelength into frequency, using the wave equation: v = fλ.)
 

Similar threads

Admissions How Can I Overcome Limited Research Experience for Grad School in Physics?
  • · Replies 7 ·
Replies
7
Views
3K
Programs How Can I Transition from Physics to a Career in Medical Physics?
  • · Replies 6 ·
Replies
6
Views
6K
Solving Physics Problem with Angles and Trigonometry
  • · Replies 4 ·
Replies
4
Views
2K
Graduate How Can Medical Students Enhance Their Understanding of Physics and Math?
  • · Replies 5 ·
Replies
5
Views
2K
How can I effectively display different types of worker coverage on a map?
  • · Replies 21 ·
Replies
21
Views
2K
High School Can I Apply Physics Concepts to a Zipline Ride?
  • · Replies 9 ·
Replies
9
Views
4K
Schools How and where do I catch up on high school physics?
  • · Replies 7 ·
Replies
7
Views
2K
Admissions Could I please get critique on my SOP? (Experimental Biophysics)
  • · Replies 9 ·
Replies
9
Views
2K
How Can High School Students Explore Physics Opportunities?
  • · Replies 9 ·
Replies
9
Views
3K
High School How Does Blackbird Leverage Wind Power to Move Faster Than the Wind?
  • · Replies 69 ·
3
Replies
69
Views
18K