Question
Briefly discuss different theories (or models) about light given by different scientists.
✓
Answer
→Many different theories are given by different scientists about the fundamental nature of light, which are as follows :
• Descartes :
→In 1637, Descartes gave the corpuscular model of light and derived Snell's law. It explained the laws of reflection and refraction of light at an interface. The Corpuscular model predicted that if the ray of light (on refraction) bends towards the normal, then the speed of light would be greater in the second medium.
• Isaac Newton :
→The Corpuscular model of light was further developed by Isaac Newton in his famous book entitled OPTICKS and because of tremendous popularity of this book, the Corpuscular model is often attributed to Newton.
→The wave theory of Huygens was not readily accepted primarily because of Newton's authority and also because, light could travel through vacuum and it was felt (or believed) that a wave would always require a medium to propogate from one point to the other.
• Huygens :
→In 1678, the Dutch physicist Christian Huygens put forward the wave theory of light.
→This wave model could satisfactorily explain the phenomenon of reflection and refraction. The model predicted that on refraction, if the wave bends towards the normal, then the speed of light would be less in the second medium. This is in contradiction to the prediction made by using the Corpuscular theory (Corpuscular model of light.) It was later confirmed by experiments and it was shown that the speed of light in water is less than the speed in air.
• Foucault :
→He carried out an experiment in 1850 and confirmed by experiment and showed that the speed of light in water is less than the speed in air as per prediction of the wave model.
• Thomas Young :
→He performed his famous interference experiment in 1801 and it was firmly established that light is actually (indeed) a wave phenomenon. The wavelength of the visible light was measured and found to be extremely small. For example, the wave length of the yellow light is about $0.6 \mu m$. Because of the smallness of the wavelength of the visible light (in comparison to the dimensions of typical mirrors and lenses), light can be assumed to approximately travel in straight lines.
• Descartes :
→In 1637, Descartes gave the corpuscular model of light and derived Snell's law. It explained the laws of reflection and refraction of light at an interface. The Corpuscular model predicted that if the ray of light (on refraction) bends towards the normal, then the speed of light would be greater in the second medium.
• Isaac Newton :
→The Corpuscular model of light was further developed by Isaac Newton in his famous book entitled OPTICKS and because of tremendous popularity of this book, the Corpuscular model is often attributed to Newton.
→The wave theory of Huygens was not readily accepted primarily because of Newton's authority and also because, light could travel through vacuum and it was felt (or believed) that a wave would always require a medium to propogate from one point to the other.
• Huygens :
→In 1678, the Dutch physicist Christian Huygens put forward the wave theory of light.
→This wave model could satisfactorily explain the phenomenon of reflection and refraction. The model predicted that on refraction, if the wave bends towards the normal, then the speed of light would be less in the second medium. This is in contradiction to the prediction made by using the Corpuscular theory (Corpuscular model of light.) It was later confirmed by experiments and it was shown that the speed of light in water is less than the speed in air.
• Foucault :
→He carried out an experiment in 1850 and confirmed by experiment and showed that the speed of light in water is less than the speed in air as per prediction of the wave model.
• Thomas Young :
→He performed his famous interference experiment in 1801 and it was firmly established that light is actually (indeed) a wave phenomenon. The wavelength of the visible light was measured and found to be extremely small. For example, the wave length of the yellow light is about $0.6 \mu m$. Because of the smallness of the wavelength of the visible light (in comparison to the dimensions of typical mirrors and lenses), light can be assumed to approximately travel in straight lines.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A force F = a + bx acts on a particle in the x-direction, where a and b are constants. Find the work done by this force during a displacement from x = 0 to x = d.
(a) The peak voltage of an ac supply is 300 V. What is its rms voltage?
(b) The rms value of current in an ac circuit is 10 A. What is the peak current?
(b) The rms value of current in an ac circuit is 10 A. What is the peak current?
Three particles of mass m each are placed at the three corners of an equilateral triangle of side a. Find the work which should be done on this system to increase the sides of the triangle to 2a.
A steel ball initially at a pressure of 1.0 × 105Pa is heated from 20°C to 120°C keeping its volume constant. Find the pressure inside the ball. Coefficient of linear expansion of steel = 12 × 10-6 °C-1 and bulk modulus of steel = 1.6 × 1011Nm-2.
Explain by graph how the electric field by thin spherical shell depends on the distance, of point from centre.
Figure shows an electrolyte of AgCl through which a current is passed. It is observed that 2.68g of silver is deposited in 10 minutes on the cathode. Find the heat developed in the $20\Omega$ resistor during this period. Atomic weight of silver is 107.9g/mole.
→Explain characteristics of electric charge.
Explain that in day to day life we can't get coherent sources using two sodium lamps.
The storage battery of a car has an emf of 12 V. If the internal resistance of the battery is $0.4\ \Omega,$ what is the maximum current that can be drawn from the battery?
→Why cannot longitudinal waves be polarized?