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by Ron Kurtus

A total of 311 comments and questions have been sent in. They are listed according to date.

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Infrared Radiation About industrial production of infrared rays India
Refraction of Light What is a simple microscope? Pakistan
X-ray Generation What are white X-rays? India
Light Snell's Law Refraction through rectangular glass block Nigeria
Electromagnetic Spectrum Generation of electromagnetic waves India
Dispersion of Light Dispersion of white light in a prism India
Refraction of Light Can a photon be refracted? UK
Dispersion of Light Why does sunlight appear to be white? Nigeria
Dispersion of Light Which wavelength deviates the most? Ghana
Light Snell's Law Why is sine used in Snell's Law? Pakistan

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First 10 letters

About industrial production of infrared rays

Topic: Infrared Radiation


May 3, 2011

I want to know about the industrial production of Infrared rays in all the wavelength range,particularly about the materials which has the ability to produce the wavelength of any particular range.

Seeni - India



There are a wide range of materials and devices for creating infrared radiation in industry. Unfortunately, we do not address industrial production methods. That is an extensive course in itself.

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What is a simple microscope?

Topic: Refraction of Light


April 6, 2011

What is a simple Microscope?

Qasim - Pakistan



The most simple microscope is a magnifying glass. Adding a second lens that is used as an eyepiece, where you put your eye close to the lens, improves the magnification.

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What are white X-rays?

Topic: X-ray Generation


April 5, 2011

What are white X-rays? What is their use?

Roopa - India



White-beam topography uses the full bandwidth of X-ray wavelengths in the incoming beam, without any wavelength filtering. White x-rays are used to study crystals using x-ray diffraction methods.

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Refraction through rectangular glass block

Topic: Light Snell's Law


April 1, 2011

pls skech a diagram for me.refraction through rectangular glass block

oluwasijibomi - Nigeria



See Refraction of Light.

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Generation of electromagnetic waves

Topic: Electromagnetic Spectrum


March 25, 2011

Explain Generation of electromagnetic waves.

sravani - India



In simple, non-mathematical terms:

Electrons have an electrical field around them. When the electrons move, they also create a magnetic field. However, when the electrons oscillate, the fields vary in amplitude and frequency, thus resulting in electromagnetic waves.

The frequency of oscillation determines the wavelength. 60 Hz results in long wavelength radio waves. Rapid oscillation, due to heating, results in visible light. High energy electrons smashing into a metal plate cause very rapid vibrations of x-rays.

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Dispersion of white light in a prism

Topic: Dispersion of Light


March 23, 2011

Does dispersion of white light take place while emerging from the opposite face of the glass prism? If so, why do diagrams of 'Dispersion of light show dispersion on the first refraction ie within the prism. Then, how is that different from refraction in a rectangular glass slab?

Susan - India



The different colors of white light travel at different speeds through glass, as a result of the different index of refraction for the various wavelength or colors. When the waves enter the glass prism at an angle, they are bent according to Snell's Law. This causes the colors to spread out while passing through the prism. At the other prism surface, Snell's Law takes place again, and the colors disperse or spread out even more.

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Can a photon be refracted?

Topic: Refraction of Light


March 22, 2011

Hi, thanks for making such a great website.
I'm slightly confused about refraction. Is it that one side of the photon(s) hits the new medium first, causing them to change direction like the line of soldiers, or is it that some beams of photons in the light hit the new medium first, and then others hit it making the light overall change direction? If so, would a single beam of photons be refracted in the same way?

Theo - UK



It is better to think of refraction in terms of waves instead of photons, which are mainly used to explain photo-electric effects.

A wavefront that hits another material at an angle will cause the wave to change directions, just as with a line of soldiers.

An experiment with a single photon would have the same effect, due to the wave-particle duality. That means that even a single photon can behave as if it was a wavefront.

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Why does sunlight appear to be white?

Topic: Dispersion of Light


March 11, 2011

Why is sunlight which is white, combination of diffrent colours of light.explain

Oguntuase - Nigeria



Sunlight is a combination of a whole range of colors or wavelengths, starting from deep red and going all the way to ultraviolet.

Sensors in your eyes detect different colours and combinations of colours. When your eyes see a combination of blue and yellow light, you perceive it as green light. Likewise, combining all the colors of sunlight, appears to be white to you.

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Which wavelength deviates the most?

Topic: Dispersion of Light


February 28, 2011

What is the wave length of
(a)least deviated colour
(b) most deviated colour

Dorleku - Ghana



The illustration in the lesson on dispersion of light clearly showed that violent deviated much more than red. There is also a chart on wavelengths.

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Why is sine used in Snell's Law?

Topic: Light Snell's Law


February 14, 2011

Why we sine of theta is used in Snell's law? why cosine can not be used?

Salman - Pakistan



The sine of the angle is used when measuring the ray of light with the line perpendicular to the surface. However, you can use the cosine if you are measuring the ray of light from the surface of the material.

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