摘要:

By considering certain properties of model systems, one can sometimes demonstrate instances of appropriate mathematical inequalities. For example, by considering the temperature‐equalization process in a set of contiguous metal blocks, one can demonstrate instances of the mathematical inequality that states that the arithmetic average of a set of non‐negative real numbers is never less than the geometric average of those same numbers. For each of six different mathematical inequalities, an appropriate model system is used to demonstrate instances of the inequality.

ISSN:0002-9505    

DOI:10.1119/1.18259

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

摘要:

Planck’s radiation formula is used to estimate the dimensionless efficiency of incandescent lamps as a function of filament temperature, with typical values of 2%–13%. Similarly, using the known spectral luminous efficiency of the eye, the efficacy of incandescent light bulbs is estimated as a function of temperature, showing values of 8–24 L W−1for bulbs of 10–1000 W. The efficiency and efficacy results compare favorably with published data and enable estimation of the filament temperature for any lamp of known efficacy.

ISSN:0002-9505    

DOI:10.1119/1.18260

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18476

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18262

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18263

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18264

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18454

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18432

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP