Quiz 21-1 answers

Here are 1, 2, and 3 - if someone would submit 4 that would be a great help to me.
1. Answer is negative
Divide the speed of light by the product of the values of the two numbers you were given: (c)/(wavelength*frequency).

2. Answer is positive
find frequency from index of refraction and wavelength: f=(speed of light)/(given wavelength in meters)
then use the answer for f in: wavelength = (speed of light)/(given index of refraction*f). Be sure to give answer in meters, not nanometers.

3. Answer is negative.
sin^(-1) of (1/given index of refraction)

4. answer is positive

sin^(-1)(((sin(given angle))/(one of given refractive indices))) - sin^(-1)(((sin(given angle))/(other given refractive index)))

multiply above by 100 for the units to match what the question asks. To give an idea of the magnitude of the answer, it should be something between 40 and 100 or so.

"helper", thanks for the help with this quiz.
Could you please run through the 4 questions with a set of numbers to work out the questions? Thank you.

What is the speed of light? is it 299792458 meters per second?

you dont have to multiply your ans by 100...that didnt work for me..just leave it in the decimal form that you get

I am not getting #4. my answer came out .005536942475. What am I doing wrong?


Two light rays, one blue with an index of refraction 1.685 and the other with a longer wavelength and an index of refraction of 1.65 are incident at 44.21° from air onto a glass surface (see sheet 9,9'). Calculate the difference in their angles with which they enter the glass. All angles are with respect to the normal to the boundary. Give your answer in 1/100 of a degree and indicate with a positive (negative) answer whether the longer (shorter) wavelength ray is at the larger angle.

you're not trying hard enough

I keep putting in my answer to number one and it's marking me wrong..anyone have any ideas? I'm using the equation n= C/V.....C= 3x10^8 and V= wavelength * frequency, and the answer is negative...i keep getting 1.697E-9 and it's marking me wrong...is there something wrong with my syntax? thanks for the help!

Can someone please show in detail how to do number 4, i tried to use the formula above but I'm just not getting it. I don't know what I am doing wrong. Please help.

you forgot to convert the unit for wavelength back to meters before calculation

I tried doing what was said above and it doesnt work how do you do it?

The wavelength of a light wave traveling in a medium is 526.5 nm and the frequency is 4.114 x1014 Hz. What is the index of refraction of the medium (see sheet 2',3) ? Indicate with a positive (negative) sign whether the speed of light in the medium is larger (smaller) than the speed of light in vacuum.

i did 3E8/(4.114E14)*(526.5) and it says this is wrong

i just read ur reply thanks! i got it

I don't get the formula given above: sin^(-1)(((sin(given angle))/(one of given refractive indices))) - sin^(-1)(((sin(given angle))/(other given refractive index)))

for the first sin is it sin^-1 (-1)? Or is suppose to be sin(-1)? the formula given is incorrect

Two light rays, one blue with an index of refraction 1.682 and the other with a longer wavelength and an index of refraction of 1.659 are incident at 44.55° from air onto a glass surface (see sheet 9,9'). Calculate the difference in their angles with which they enter the glass. All angles are with respect to the normal to the boundary. Give your answer in degrees and indicate with a positive (negative) answer whether the longer (shorter) wavelength ray is at the larger angle.

use the formula given:
sin^(-1)(((sin(given angle))/(one of given refractive indices))) - sin^(-1)(((sin(given angle))/(other given refractive index)))

sin^-1(((sin(44.55))/(1.682)))-sin^-1(((sin(44.55))/(1.659))) = boom your answer in positive and you don't have to multiply by 100

Question 4: (1 point)

Two light rays, one blue with an index of refraction 1.695 and the other with a longer wavelength and an index of refraction of 1.623 are incident at 40.73° from air onto a glass surface (see sheet 9,9'). Calculate the difference in their angles with which they enter the glass. All angles are with respect to the normal to the boundary. Give your answer in degrees and indicate with a positive (negative) answer whether the longer (shorter) wavelength ray is at the larger angle.

The answer i am getting is 1.06434. I am making it positive and i am trying to use that formula. Can you please try my numbers and see if you get the same answer? Maybe there is a problem with my quiz. Thank you for your help.

Thanks guest, i tried it again. Thank you!

for # 4, do not multiply by 100. and this (sin^(-1)) means inverse sin.

yo for real look at the cd for like 2 seconds and you will figure out what you're doing wrong and you won't wonder why you got below avg on the last test.

1*sin(angle given)/n(given)-1*sin(angle given)/n(other given n)
Note: the 1 is the n of air