Department of Basic Sciences

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Browsing Department of Basic Sciences by Author "Imtiaz Ahmad"

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    Filament temperature of low power incandesecent lamps: stefan-boltzmann law
    (2010) Imtiaz Ahmad; Sidra Khalid; Ehsan Khawaja
    An undergraduate experiment using commercially available low power incandescent lamps was performed. The results obtained, for higher temperature of the filament (say above 1000 K), were compared with those calculated using a simple model, based on transfer of electric power predominantly into Planck’s radiation channel through Stefan- Boltzmann law. The agreement between the results and the theory was quite satisfactory. Measurement of filament temperature to confirm theoretical results, included in the present work, is expected to give a student more confidence in the theory.
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    On the determination of refractive index and thickness of thin dielectric films from measurement of transmittance
    (World Scientific Publishing Company, 2012) Zaheer Hussain Shah; Imtiaz Ahmad; Q. A. Tahir; Ehsan Ellahi Khawaja
    Refractive index and thickness of a transparent ¯lm (ZnS) on a transparent substrate (BK-7 glass) have been determined from measurement of normal incidence transmittance, using di®erent methods. Some of the methods considered here are most widely used, as is apparent from the literature. The outcome of this study could help a researcher in selecting an appropriate method for such an application. The values of the refractive indices determined by di®erent methods were found to be close to each other (within 0.5%). However, large (up to 4.4%) di®erences existed in the values of the thickness determined by di®erent methods.