is light a particle or a wave?

Yes                                   .

Light has a dual nature. Scientists accept the evidence that supports this dual nature of light :
Sometimes light behaves like a particle (called a photon), which explains how light travels in straight lines and why the energy of light is quantized. 
Sometimes light behaves like a wave, which explains the phenomena of reflection, refraction, diffracts and interference.

Light is light. In instances where it's measured with a wave measuring system, it acts like a wave; if measured with a particle detecting system, it acts like a particle. So, it's neither one, it's just something that acts like a particle under some conditions and like a wave under other conditions.

Light Is Also a Particle!

Now that the dual nature of light as "both a particle and a wave" has been proved, its essential theory was further evolved from electromagnetics into quantum mechanics. Einstein believed light is a particle (photon) and the flow of photons is a wave.


Light is It a Wave or a Particle? - Canon Global

No. Light is a wavefunction. When measured, the wavefunction will collapse into discrete units like particles but the probabilistic distribution of these particles will follow the original wavefunction.

No it is not. It BEHAVES with some properties like a particle and some properties like a wave.  It can be modeled as either or as both depending on the situation.  But light IS light.  It ISN'T anything else.

Yes, it is.                      

Some would say it is both and neither at the same time some would also say that we have built things to detect that we have defined rather than allowing it to define itself to us...

N.Shadows