how can we say light does not need light to travel
No, light doesn't need a physical medium, like air, to travel. As a matter of fact, light travels the fastest it possibly can, 2.98 * 10^8 meters per second, in a vacuum, like space. If light couldn't travel without a medium, then Earth wouldn't receive any light from the Sun.
actually light is nothing but combination of so many Waves. so we can say that light and waves are not different things that means if a light can move through a medium we an say that the waves an also move through that so medium refers the same meaning both in terms of light and waves
Nothing (say a vacuum). The medium is what the sound travels through.
Light can travel through a "vacuum" because the vacuum has a medium to transport light. Light can travel through a vacuum due to its dual nature; it can exhibit behaviours of either particles or waves, depending on the conditions under which it is observed, a situation called "particle/wave duality". A wave would need a medium to propagate (move) through, but a particle is like a tiny bullet, and can move independently (though still affected by) of the medium. In the case of a vacuum (by definition a space containing no matter), light behaves like a particle (called a photon), and moves through it in a straight line, unaffected. If, in that vacuum, it encounters something else, say a diffraction grating, its wave nature appears and it diffracts (spreads out), exactly as a wave would, but a particle would not.
Light slows down when going through a medium. This is not to say that the speed of light, c, slows down. It doesn't - c remains constant - rather the light bounces randomly around the medium on its way to its destination, which increases the time it takes for the light to traverse through the medium.
No, light doesn't need a physical medium, like air, to travel. As a matter of fact, light travels the fastest it possibly can, 2.98 * 10^8 meters per second, in a vacuum, like space. If light couldn't travel without a medium, then Earth wouldn't receive any light from the Sun.
Light waves can travel through empty space. You might say that the empty space is the medium in this case.
actually light is nothing but combination of so many Waves. so we can say that light and waves are not different things that means if a light can move through a medium we an say that the waves an also move through that so medium refers the same meaning both in terms of light and waves
Any material through which any wave travels is called a medium. Ocean waves travel through the medium of seawater. Sound cannot travel through outer space, because there is no medium there to support sound waves. Mechanical waves such as sound and vibration require a medium through which to travel. Usually air, or a solid or liquid - matter in other words.
Nothing (say a vacuum). The medium is what the sound travels through.
Light can travel through a "vacuum" because the vacuum has a medium to transport light. Light can travel through a vacuum due to its dual nature; it can exhibit behaviours of either particles or waves, depending on the conditions under which it is observed, a situation called "particle/wave duality". A wave would need a medium to propagate (move) through, but a particle is like a tiny bullet, and can move independently (though still affected by) of the medium. In the case of a vacuum (by definition a space containing no matter), light behaves like a particle (called a photon), and moves through it in a straight line, unaffected. If, in that vacuum, it encounters something else, say a diffraction grating, its wave nature appears and it diffracts (spreads out), exactly as a wave would, but a particle would not.
Light slows down when going through a medium. This is not to say that the speed of light, c, slows down. It doesn't - c remains constant - rather the light bounces randomly around the medium on its way to its destination, which increases the time it takes for the light to traverse through the medium.
From rectilinear propagation of light.
No, the amplitude of light does not change when it passes from one medium to another. Amplitude is a characteristic of the light wave itself and does not depend on the medium it is passing through. The speed and direction of light may change when passing through different mediums, but not its amplitude.
No, radio waves are a type of electromagnetic wave that can travel through empty space without needing a medium. They propagate through a vacuum and do not require a physical medium such as air or water to travel from one point to another.
No
Light emitted by any light source - say, by a lamp, or by the Sun - travels in all directions.