PLEEASE HELP I AM LOST Thank you.

[madd_bm]

PLEEASE HELP! I AM LOST! Thank you.

I have two questions:

1. Electromagnetic waves also can form standing waves. In a standing wave pattern formed from microwaves, the distance between a node and an adjacent antinode is 0.44 cm. What is the microwave frequency.
I keep getting the wrong answer here. I am not sure what I am doing wrong. It seems like I am missing some information, but this is the entire question...I think I am confused and I really don't know where to begin. If you could explain to me where to start I will probably be able to figure this one out. The class is an online class and I don't get much help from the instructor...thanks.


2.
In experiment 1, unpolarized light falls on the polarizer in the figure below. (see attachment untitled1) The angle of the analyzer is θ = 62.5°. In experiment 2, the unpolarized light is replaced by light of the same intensity, but the light is polarized along the direction of the polarizer's transmission axis. By how many additional degrees must the analyzer be rotated so that the light falling on the photocell will have the same intensity as it did in experiment 1? Explain whether θ is increased or deceased by this additional rotation. (Use a positive number to indicate an increase in the angle. Use a negative number to indicate a decrease in the angle.)

I started with this: 1/2cos^2theta = .10661
but I'm not sure what to do from there.

The attempt at a solution
cos^-1(.10661) = 83.8deg., then 83.3-62.5 = 21.3...but that is wrong.

Thank you.

 

[alphysicist]

Hi madd_bm,

I have two questions:

1. Electromagnetic waves also can form standing waves. In a standing wave pattern formed from microwaves, the distance between a node and an adjacent antinode is 0.44 cm. What is the microwave frequency.
I keep getting the wrong answer here. I am not sure what I am doing wrong. It seems like I am missing some information, but this is the entire question...I think I am confused and I really don't know where to begin. If you could explain to me where to start I will probably be able to figure this one out. The class is an online class and I don't get much help from the instructor...thanks.

Can you show what you did that gave the wrong answer?

 

[thomate1]

Dear student,

I am sorry to hear that you are feeling lost and struggling with these questions. I will try my best to provide some guidance and help you understand the concepts better.

For the first question, it is important to note that the distance between a node and an adjacent antinode in a standing wave pattern is equal to half the wavelength. So, we can use this information to find the wavelength of the microwaves by dividing the given distance of 0.44 cm by 2. Once we have the wavelength, we can use the formula c = λf (where c is the speed of light, λ is the wavelength, and f is the frequency) to calculate the frequency of the microwaves.

Now, for the second question, it is important to understand the concept of polarized light and how it interacts with a polarizer. In experiment 1, unpolarized light falls on the polarizer and some of it gets transmitted through the analyzer at an angle of 62.5°. In experiment 2, the light is already polarized along the direction of the polarizer's transmission axis, which means all of it gets transmitted through the analyzer. So, to achieve the same intensity as in experiment 1, the analyzer needs to be rotated by an additional angle. The formula for analyzing polarized light is I = I0cos^2θ, where I is the intensity after passing through the analyzer, I0 is the initial intensity, and θ is the angle of the analyzer. You can use this formula to calculate the angle by substituting the given values and solving for θ.

I hope this helps. If you are still unsure, I would suggest reaching out to your instructor or seeking help from a classmate or tutor. It is important to fully understand these concepts in order to succeed in your class. Good luck!