the face of the thermo-pile, near the second mirror. No very large effect will beproduced, except when the face of the thermopile is in theposition which in the previous experiment was occupied bythe sheet of paper. The rays from the ball fall on the firstmirror and are there reflected in a… … Fig. 75. 1 These are usually made of copper beaten into a spherical form,polished on the inside and coated with silver, and should be some 50 cm.across. A point midway between the centre of the surface and the centreof the sphere is called the principal focus. If a luminous source be placedat this…
Heat · Light
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