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What color of light is being absorbed by the solution shown in the Self Check image.
Answer
Since the solution appears orange, it is probably absorbing blue light. Blue light is in the range 430 nm - 490 nm. The solution is probably transmitting red, orange, yellow, green, and violet light (all colors except blue).
The Spectronic 20™ in the Self Check video is being set for maximum absorbance. Would any subsequent measurements be accurate? Why or why not?
Answer
Accurate absorbance measurements cannot be obtained. The maximum absorbance has been set off the scale of the spectrophotometer. Instead the maximum absorbance should be set at the infinity line.
Which of the following are likely to happen if the instrument has not warmed up for fifteen minutes prior to use?
- Recorded absorbance readings will be inaccurate.
- The sample will be automatically ejected from the sample chamber.
- No light will pass through the sample.
Answer: A. Recorded absorbance readings will be inaccurate. Since the phototube detector is sensitive to temperature changes, the source lamp must reach a constant temperature before absorbance readings are consistent. The lamp takes about fifteen minutes to reach a constant temperature. |
