The ophthalmoscope : a manual for students / by Gustavus Hartridge.

  • Gustavus Hartridge
Date:
1907
Catalogue details

Licence: In copyright

Credit: The ophthalmoscope : a manual for students / by Gustavus Hartridge. Source: Wellcome Collection.

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    mirror equal to the distance of the candle in front of it, and an observer’s eye placed at e would receive the rays from c as if they came from c . Fig. 2. si. The mirror, c. The candle, c'. The virtual image of the candle. e. The eye of the observer receiving rays from mirror. The image of the candle so formed by a plane mirror is called a virtual image. Reflection by a Concave Surface A concave surface may be looked upon as made up of a number of planes inclined to each other. Parallel rays falling on a concave mirror are reflected as convergent rays, which meet on the axis at a point (f, Fig. 3) called the principal focus, about equally distant from the mirror and its centre c. The distance of the principal focus from the mirror is called the focal length of the mirror.