Laboratory exercises to accompany Carhart and Chute's First principles of physics . lens, by means of this marked line, and not bymeans of the numbers on the meter stick. At one end of the meter stick place an incandescentlamp or other light, and directly in front of the light ascreen with a translucent window in it to serve as anobject (Fig, 61). (a) Set the lens at its focal length from the illuminatedscreen. The object is now at the principal focus of the STUDY OF A CONVERGING LENS 101 lens. Move the opaque screen on the other side of thelens, and note whether or not an image is formed on t
Laboratory exercises to accompany Carhart and Chute's First principles of physics . lens, by means of this marked line, and not bymeans of the numbers on the meter stick. At one end of the meter stick place an incandescentlamp or other light, and directly in front of the light ascreen with a translucent window in it to serve as anobject (Fig, 61). (a) Set the lens at its focal length from the illuminatedscreen. The object is now at the principal focus of the STUDY OF A CONVERGING LENS 101 lens. Move the opaque screen on the other side of thelens, and note whether or not an image is formed on thisscreen. The formation of an image means that the raysof light leaving the lens converge. If an image is notformed, the rays leaving the lens are either parallel ordivergent. When the object is at the principal focus, whatis the direction of the rays leaving the lens? (Recall themethod of finding the principal focus.) (b) Move the lens nearer the illuminated screen thanin (a). The object is now within the principal the screen to ascertain whether or not an image is. Fig. 61. formed. Look through the lens at the illuminated screenand describe its appearance. In this case ivhat do youthink is the direction of the rays leaving the lens? Explain,(e) Place the lens so that the object is at a distance oftwice the focal length. Place the screen at an equal dis-tance on the other side of the lens. Is the image on thescreen erect or inverted ? l Is it larger or smaller than theobject ? When the object is at txcice the focal length from thelens comjj are (1) the relative distances from the lens of objectand image. (2) the relative size of object and image. At 1 In case a sharp image is not formed at twice the focal length, find theshortest distance between the object and the screen at which a distinctimage of the object can be formed on the screen. Compare the objectand ima^e distances with each other and with twice the focal length. 162 LABORATORY EXERCISES what distance fr
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectphysics, bookyear1913
