What is the weight of light?

Question

At a recent training course i went on the trainer said that light could not be weigh because of the uncertaincy principal. Yet one of my friends says he once found an article with the weight listed. Anyone have any difinitive answers?

Answer 1

light has no mass, therefore no weight.

However, if all the energy of the light were somehow converted to mass, its mass would be m=E/c^2.

Answer 2

Weight Of Light

Answer 3

ok 2 separate issues here. Light 'bends' in a gravitational field. As previously stated the sun's gravitational field distorts the space-time surrounding it, like any massive body, and the light follows a geodesic path.In this respect the light beam behaves as if it had weight.
Now mass (and E=(delta)mc^2 )
Take a gamma-ray photon with E>hf>1.022Mev
Fire it close to a massive nucleus, say and an electron and a positron will appear.
The total (rest ) mass of this particle/antiparicle pair=1.82x10^-30Kg
Using E=mc^2 gives E= 1.638x10^-13J
and 1.022x1.602x10^-13=1.638x10-13J approx
(1Mev= 1.6x10^-13J)
In fact pair production can occur all the time, provided Energyxtime< h/(2pi) (quantum of action is less than Plank's const/2pi- Heisenberg uncertainty principle)

Answer 4

Light does not have weight like you and I because light has no mass....or "rest mass" or "invariant mass" as it's sometimes called.

If you could weigh light it wouldn't weigh anything.

BUT light does have momentum.

This means that even though light doesn't weigh anything, when it smacks into something it can exert a force on it. This oddity stems from the fact that the speed of light is a constant. Here on Earth if a car zips by you on the freeway, you could speed up such that the car is going 0mph relative to you, but with light this isn't the case. No matter how fast or slow you go, the light will appear to be traveling at the same speed that it always was.

Because of this, there is no reference frame in which light is at rest and it has no invarient mass like you and I.

Because it can exert a force on something due to it's having momentum, it can be said to have a simulated mass, or, what's sometimes called a "relativistic mass"..though momentum is a more proper term.

Answer 5

I read your problem with very sincerely and with full concentration.I understood your requirement but don't worry some Easy Ways to Lose Weight Without Starving
You can stage a coup on calories without ruining your life or eating a single rice cake: Just follow this simple advice. You might even be surprised by how easy (and delicious) some of these tips are to follow:

Always Eat a Breakfast:
No more Lucky Charms—you want some protein and fat. Scrambled eggs and a few sausage links will keep you fuller longer than an airy doughnut will.

Eat More!:
We're talking three good snacks and three healthful meals. But what do you serve during the bowl game if you can't have chips and dip? Mixed nuts—especially almonds—will satisfy your craving for something crunchy while helping to build muscle.

Just Say No to Starches:
Foods like pasta, white bread, and potatoes make you fat. If you must have pasta, make yours whole-wheat. Same goes for bread, and swap white potatoes for sweet potatoes. Just don't eat too much! A perfect example of a great swap is these crispy sweet potato fries. You'll never go back to regular potatoes.

Lift Weights:
Yes, you have to hit the gym, and no, lifting beer cans during happy hour doesn't count. The muscles you build will not only improve your performance, they'll metabolisms you burn calories long after your workout is over.

Think Before You Eat:
Don't just stuff your face with the stale cookies left over from the holidays, eat what tastes good and what's good for you. Take your time eating; you'll stay fuller longer. Here are 7 ways to harness your hunger from a grumbling stomach.

But Have Fun Once in a While—or Once a Week:
Stifle those cravings for too long and you'll be miserable and might fall off your new plan forever. Just splurge reasonably—two slices of pizza, not the whole thing.

Go Low-Curb:
it’s the easiest way to drop weight fast. The cravings are hard at first, but it gets easier—especially when you see the results.

Run Intervals:
it’s easier to alternate between hard and easy running instead of going for a long run—especially if you don't like running. Plus, you'll be done faster and burn more fat. Break your speed limits by boosting your speed with intervals. You'll not only get faster, but your gut with flatten in no-time.

Never, Ever Drink Sweetened Soda:
But go ahead have a glass of wine now and then. Low-crab beer is fine, too, in moderation.

Don't Fear Fat:
It makes you feel full, helps control your appetite, and your body needs it. Of course, some fat is good while others are bad. See How Fat Attacks, and how you can make it work for you.

Just follow this simple advice. You might even be surprised by how Quick and easy to lose weight.

Answer 6

Well, I can tell you for a fact that my scales are balanced and I spent about five minutes chasing around here trying to get some light to stay right on the scale platter.I was unsuccessful in doing that. Each time I moved to view the reading on my pointer the light went off somewhere. So I have to report that light is probably weightless.

To check my test so that I could be positively truthful to you, I went into the bathroom (my wife keeps a set of scales in there also). I looked at the scale with the light on, and with the light off.
With the light on the scale read Zero. With the light off the room was dark and I have no idea what the scale said. So my response is that "To weigh you must have light."

Answer 7

By definition, weight is a measure of the force a body exerts on anything freely supporting it. This is difficult to achieve for light. For now, we take it light has a dual nature. Particulate and energy pockets. Light can be drawn gravity. Going by the definition of weight I'd say yes for mass but probable for weight (on a suitable near black hole planet).

Answer 8

Everybody is wrong so far. Einstein's equation E = mc^2 works both ways. A given mass contains a certain total energy; a given quantity of energy has a certain equivalent mass. Light has energy, therefore it has an equivalent mass precisely according to E = mc^2. When light passes near a star, it is deflected according to ITS OWN MASS and the mass of the star - if the light had no mass, it would not be deflected at all.

Answer 9

You don’t need to exercise for hours on end. Short, sharp sets of exercise will produce better results in the event you work hard. Get a skipping rope, skip for two minutes, do push ups for a minute or so, skip for two minutes, rest for just one minute. Then change the push as much as something else like sit ups along with do the set again. Repeat it five times and it’s a rapid, effective workout that will recover results than a long manage or swim.

Answer 10

You don’t need to exercise for long periods of time. Short, sharp sets of exercise will produce better results if you work hard. Get a bypassing rope, skip for two units, do push ups for 1 minute, skip for two minutes, rest for example minute. Then change the push around something else like sit ups as well as do the set again. Repeat it five times and it’s a simple, effective workout that will improve results than a long work or swim.

Answer 11

Ask for your entrée being served on a bed of greens rather than bed of pasta or mashed carrots.