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| Graukeil m (light-absorbing wedge of uniformly increasing density) | |||
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neutral density wedge : 2 phrases in 1 subject |
| Optics branch of physics | 2 |
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| |||
| Graukeil m (light-absorbing wedge of uniformly increasing density) | |||
|
neutral density wedge : 2 phrases in 1 subject |
| Optics branch of physics | 2 |