 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Measurement of a Thermal Expansion Coefficient for a Metal by Diffraction Patterns from a Narrow Slit) ผู้เขียน: Piyarat Bharmanee, เขมฤทัย ถามะพัฒน์, Pramot Satasuvon, พิเชษฐ ลิ้มสุวรรณ สื่อสิ่งพิมพ์:pdf AbstractIn this work, we made an effort to determine linear coefficient of thermal expansion of metal using single-slit diffraction. An aluminium strip was used as sample. The design of the apparatus for this method allows for the width of a single slit to increase by the same amount as the thermal expansion of a length of a strip or a rod of a material. The increase in the slit width, hence the linear expansion, can be determined by measuring the fringe width. A He-Ne laser with a wavelength of 632.8 nm was used to obtain a diffraction pattern for the single slit. The value of the linear coefficient of thermal expansion of the material can then be calculated using the principle knowledge of diffraction equation and thermal expansion. The experimental result was found that the linear coefficient of thermal expansion of aluminium is 22.512 ? 10-6 (C?)-1, giving a 2.545 % error. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Measurement of Verdet Constant in Diamagnetic Glass
Using Faraday Effect) ผู้เขียน:เขมฤทัย ถามะพัฒน์, Piyarat Bharmanee, พิเชษฐ ลิ้มสุวรรณ สื่อสิ่งพิมพ์:pdf AbstractMany materials exhibit what is called circular dichroism when placed in an external magnetic
field. An equivalent statement would be that the two circular polarizations have different refractive
indices in the presence of the field. For linearly polarized light, the plane of polarization rotates as it
propagates through the material, a phenomenon that is called the Faraday effect. The angle of rotation
is proportional to the product of magnetic field, path length through the sample and a constant known as
the Verdet constant. The objectives of this experiment are to measure the Verdet constant for a sample
of dense flint glass using Faraday effect and to compare its value to a theoretical calculated value. The
experimental values for wavelength of 505 and 525 nm are V = 33.1 and 28.4 rad/T m, respectively.
While the theoretical calculated values for wavelength of 505 and 525 nm are V = 33.6 and 30.4
rad/T m, respectively. |