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Have you ever wondered why things show colour? Well when light is incident on a surface, light of certain wavelengths are absorbed and we see the complement colours.For example a green surface absorbs light of all colours other than green. But a white surface is a surface that reflects out light of all wavelengths unlike a black surface which absorbs all ...


5

The shoes and shoelaces are made from different materials. The shoelaces contain a substance that fluoresces: it converts the UV light to blue light so that it becomes visible to you. The remainder of the shoes does not contain this substance, so it just absorbs or reflects the UV light, still invisible to you. There are many blue fluorescent substances, so ...


2

You've come to a long time phyilosophical question: does a field actually "exist"? We cannot measure fields. There is no instrument able to measure a "field". The instrument you use to measure electric field is actually based on forces. The instrument detects an electric force and then it deduces the value of the $E$ field. In an empty ...


1

I understand that EM waves are self-perpetuated due to the interactions between changing electric and magnetic fields as described by Maxwell's third and fourth equations, but I'm stuck conceptually on what they are if there are no electrons or conductors around. people were stuck like you begininning of the 20th century thinking the EM waves required a ...


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