Briefly describe what planck and einstein contributed to the concept of quantum theory

Max Planck was studying the emission of light by hot objects. He believed that the hot objects did not emit energy continuously, as would be expected if it were in the form of waves. Instead he suggested that the object emits the energy in small, specific amounts called quanta. A quantum is the minimum quantity of energy that can be lost or gained by an atom. He proposed the following relationship between a quantum of energy and the frequency of the radiation: E = hn. E represents the energy in joules of a quantum of radiation, n is the frequency of the radiation emitted, and h is a constant known as Planck’s constant. Albert Einstein introduced the idea that electromagnetic radiation has a dual wave-particle nature. Example: white light exhibits many wavelike particles, it can also be thought of as a stream of particles. Each particle of light carries a quantum of energy. He called these particles photons. A photon is a particle of electromagnetic radiation having zero rest mass and carrying a quantum of energy.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.