Ah, I see. I was confused about the wording, because I thought "proper time" (t0) was the time measured by the person on earth, but "proper time" is actually the time that is measured by the person that is moving on the spaceship. Thank you so much for your help!
I did know that relativistic time (where observer is moving) should be shorter than proper time (where observer is stationary), but our professor gave us this:
proper time = t0
relativistic time = t
relativistic time = t0 / sqrt[1 - (v/c)^2], which doesn't give the right relationship...
so I can...
Homework Statement
A certain star is 76.6 light-years away. How many years would it take a spacecraft traveling 0.946c to reach that star from Earth, as measured by observers on Earth? How many years would it take to reach that star from Earth, as measured by observers on the spacecraft ...
Ah, I see. I thought that the infared rays were only the ones that landed on level 3, but they can land on level 3, 4, OR 5? However, visible rays ONLY land on level 2 and UV rays ONLY land on level 1, is that correct? Thanks for your help!
Homework Statement
How many transitions involving the hydrogen energy levels shown correspond to photons of infrared light? The infrared range is less than 1.8 eV
Homework Equations
Paschen Lines = Infared wavelengths
The Attempt at a Solution
I thought that since Paschen lines =...
Homework Statement
Two antennas located at points A and B are broadcasting radio waves of frequency 96.0 MHz, perfectly in phase with each other. The two antennas are separated by a distance d=12.40m. An observer, P, is located on the x axis, a distance x=55.0m from antenna A, so that APB...
Homework Statement
Two antennas located at points A and B are broadcasting radio waves of frequency 96.0 MHz, perfectly in phase with each other. The two antennas are separated by a distance d=12.40m. An observer, P, is located on the x axis, a distance x=55.0m from antenna A, so that APB...
Homework Statement
Two slits separated by a distance of d = 0.12mm are located at a distance of D = 780mm from a screen. The screen is oriented parallel to the plane of the slits. The slits are illuminated by a coherent light source with a wavelength of lambda = 549E-6 mm. The interference...
I tried converting eV to joules, which gave me 1.27E-16 joules, which gave me 8.36E6 m/s but that is wrong too. I think the units for mass (kg) are correct, I'm not sure what I have wrong...
Homework Statement
What is the speed of a 796eV electron?
Homework Equations
E = hc/lambda
E = hv
The Attempt at a Solution
I'm not sure how to get a value for meters... I know if I take h (plank's constant) and divide the electron, I will get 4.14E-15 ev*s / 796 eV = 5.20E-18...
I didn't know that all virtual images are upright, that is good to know!
However, if Part F is true, I still have something else wrong, as I tried: TFTFTT
So I'm not sure what other one I have wrong...
I guess my prof said that a diverging lens could possibly form an inverted image, although I'm not sure how.
I also already tried that combination: TFTFTT
So I must either have another one wrong or something... not sure...
Homework Statement
Starting with a real object, which of the following statements are TRUE about the image formed by a single lens? (Choose ALL correct answers, e.g. B, AC, CDF.)
A) For a converging lens an object has to be placed between the focal length and the lens in order to form a...
yep, I'm awful at trig so that isn't surprising. haha.
i'm still not getting it right though: if i use that identity, i get:
1 * 2 sin theta cos theta = 1.51 * sin theta
If I divide the left by sin theta, the sin theta cancels out (right?), leaving me:
2 cos theta = 1.51
which gives me a...
Homework Statement
A beam of light in air strikes a piece of glass (n=1.51) and is partially reflected and partially refracted. Find the angle of incidence if the angle of reflection is twice the angle of refraction.
Homework Equations
n1sintheta1 = n2sintheta2
The Attempt at a...
I'm so sorry - I forgot the n in the right side of the equation, it should read like this:
n * [ x / sqrt(x^2 + h^2) ] = [ d / sqrt(d^2 + h^2) ]
when I solved this, I got x = d/n
But i only got that one equation...
would solving that result in x = d/n?
That is what I got. Here is how I got it:
(x^2 + h^2) / x^2n^2 = (d^2 + h^2) / d^2
1/n^2 + h^2/x^2 = 1 + h^2/d^2
1/n^2x^2 = 1/d^2
nx = d
x = d/n
Is that right? Thanks for your help on this I appreciate it by the way
I must have done something wrong, because x can't equal d. x is less than d because of the index of refraction (in the diagram).
Here is how I got the formula:
the theta for the apparent angle of where the fish appears is I called theta apparent
the theta for the angle of where the fish...
Homework Statement
solve for x:
[ x / sqrt(x^2 + h^2) ] = [ d / sqrt(d^2 + h^2) ]
I need to solve for x.
Homework Equations
sq rt * sq rt = what is inside the square root
square both sides of an equation
The Attempt at a Solution
Can anyone help me remember how to get...
I did apply Snell's law, and I did tak the refraction of light into account. that is how I got the equation (x is the distance of the actual fish, where d is the distance of the virtual fish). I just don't know how to solve the algebra, can you help me with that?
OK - I managed to find a formula to solve for X, but now I'm having trouble with the algebra:
[ x / sqrt(x^2 + h^2) ] = [ d / sqrt(d^2 + h^2) ]
Can anyone help me remember how to get rid of the sqrt of x on the bottom of the left hand side? If I multiply by the sq rt of the ( ) I will have to...
Homework Statement
After finishing your physics classes with the firm conviction that the questions
were strange and out of touch with reality, you decide to take up spear fishing. While
wading through water (of index of refraction=n and depth h) you spot a fish that appears
to be a...
Homework Statement
A 1.10m long FM antenna is oriented parallel to the electric field of an EM wave. How large must the electric field be to produce a 1.28 mV voltage between the ends of the antenna?
Homework Equations
u = EoErms^2
I = uc
Intensity = Power / area
The Attempt at a...
Homework Statement
A laser beam enters a 10.0cm thick glass window at an angle of 30 degrees from the normal. The index of refraction of the glass is 1.46. At what angle from the normal does the beam travel through the glass?
Homework Equations
sin theta 1 / sin theta 2 = n1 / n2 = v1 /...
Homework Statement
A super nova releases 1.9E45 J of energy over a 10 day period. It is 1560 ly from earth. A detector, facing the star, is a disk of radius 7cm. How much energy reaches the detector? (The detector is in orbit, so it can face the star for the entire 10-day period)
Homework...
Sorry, I should have scanned the problem earlier...I attached it here - can you see if it makes more sense to you now? Thanks!
The only part I don't understand is the current on the middle block (and hence, the force on the middle block). I get the first and third parts.
Thanks!