Can light be measured it terms of weight???????????

The thing is, Scientiencs, sorry for my spelling.... what they say is the gravity expunged by a black hole will draw all light to the body of the particular black hole.....

if that is so then light can be weighed so what is lthe weight of light??????????


you can give me stars for this question if you want but it wont guarentee the points..........

20 Answers

  • .
    Lv 6
    1 decade ago
    Favorite Answer

    Starting by adopting a particulate model of light, then photons are packets of light energy. The packets of energy or the photons are mass-less, hence they travel at the speed of light. However, Einstein's Special Theory of Relativity relates energy and mass in the famous equation: -


    Where 'c' is the speed of light and 'm' the energy 'E' equivalent mass. Einstein's General Theory of Relativity describes a gravitational field as the distortion of space-time by the presence of mass and energy. Thus, this theory (published in 1915) predicts that light (specifically star light) passing close to the edge of a strongly gravitating body, such as our Sun, will be deflected through an angle, which may be measured during an eclipse of the Sun. Einstein's prediction was confirmed by photographic experiments conducted by a team led by Eddington in 1919. The gravitational deflection of star light has been confirmed more accurately, many times, since. Hence, although photons have no mass their energy equivalent mass is influenced by strong gravitational fields. Another example of gravitational bending occurs with intervening galactic bending, of more distant quasar light - with the most famous example being 'Einstein's Cross'.

    It is also true that because of the energy equivalent mass of light, it will be drawn into a black hole's gravitational well and can not escape if it crosses the event horizon.

  • 1 decade ago

    Light actually has wave/particle duality.

    Expressing the carrier, (proton), as a weighable particle is not feasible though.

    You see, light is a wave, with various wave-lengths from ultra-violet, through visible, to infra-red and beyond, But the wave needs a carrier, which happens to be a particle, but the weight of the particle is, for all intents and purposes, zero.

    If it did have mass, light would be deadly, especially since it travels at 186282 miles per second.

    Passage taken from wikipaedia.

    In physics, the photon is the elementary particle responsible for electromagnetic phenomena. It is the carrier of electromagnetic radiation of all wavelengths, including gamma rays, X-rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves. The photon differs from many other elementary particles, such as the electron and the quark, in that it has zero rest mass;[3] therefore, it travels (in vacuum) at the speed of light, c. Like all quanta, the photon has both wave and particle properties (“wave–particle duality”). Photons show wave-like phenomena, such as refraction by a lens and destructive interference when reflected waves cancel each other out; however, as a particle, it can only interact with matter by transferring the amount of energy

    Source(s): wikipaedia
  • 1 decade ago

    No light cannot be measured in weight. It can be measured in terms of energy. Funny thing is u can still measure the momentum of photons. Recall that the classical momentum of an objects is its mass times the velocity. But in quantum mechanics the momentum of massless particles is a function of their wavelength and the Planck's constant.

    I'm not sure on this but i think according E=MC^2 isn't energy and mass proportional to each other since C is just a constant.

  • Asker
    Lv 6
    1 decade ago

    It is an old question if light has mass or not. Light doesn't have a sensible weight but gravity exerts effect on it. Light sometimes behaves as a particle and sometimes behaves like a wave.

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  • Anonymous
    1 decade ago

    yes, well its an age old argument is light a wave or particle? if you decide particles, then yes u can measure light as weight in terms of photons. It was some years since my physics a-levels, but I think u measure the number of photons in light depending on the energy levels it emits.

    Indeed, been corrected, photon rest mass is massless.....but how about photon mass when its not at rest?

  • 4 years ago

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  • 1 decade ago

    OK..look at it this way..massive objects curve space time..light travels in a minimum path called a geodesic.

    ..Or if you shone a torch into a lift acelerating upwards, the light would travel in a parabola like a projectile moving in a gravitational field..the accelerated lift interior is experimentally indistinguishable from a (local) gravitational field (you have weight, objects accelerate to the floor if dropped etc)..therefore light bends near massive objects.

    Source(s): General relativity for dummies..anyone fancy a pint?
  • 1 decade ago

    well, no, energy does not have any sort of force acted upon it in terms of weight.

    light is energy.

    black holes are the remains of massive star explosions that have so high of a gravitational pull, they rip holes in space. light itself is often distorted in a black hole, but that does not mean it has any weight

  • 1 decade ago

    Well, no it is not that light has wieght, but instead light is something that is defined as our universal speed limit. It defines time, and maximum speed in this universe. Gravity is the ripples that distorts that.

  • Anonymous
    1 decade ago

    weight is gravities effect on mass. photons (what light is) are massless. so they have no weight. gravity effects everything, it doesnt matter if it has mass or not.

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