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Free download in PDF UV-Visible Spectroscopy Multiple Choice Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams like UPSC, NDA, SSC etc. These short solved questions or quizzes are provided by Gkseries./p>
(1)
Solvatochromism is the ability of a substance to change colour due to
[A]
A change in wavelength of the incident radiation
[B]
A change in the solvent viscosity
[C]
A change in molecular weight of the substance
[D]
A change in the solvent polarity
Answer: A change in the solvent polarity
(2)
Two compounds A and B have molar absorptivity as 1200 and 15,000 mol lit -1cm -1 respectively. Which of the following statements is correct regarding them?
[A]
Compound A can be detected at very low concentrations than compound B.
[B]
Compound B can be detected at very low concentrations than compound A.
[C]
Both compounds can be detected at very dilute concentrations.
[D]
Molar absorptivity have no influence on the detection of compounds.
Answer: Compound B can be detected at very low concentrations than compound A.
(3)
Which of the following shows bathochromic shift in polar solvent
[A]
Water
[B]
Ethanol
[C]
Ethylene
[D]
Chloroform
(4)
The colour of a substance perceived by human eye is
[A]
Same as that the substance emits in flame
[B]
Same as that the substance absorbs
[C]
Not same as that the substance absorbs
[D]
Not same as that the substance emits
Answer: Not same as that the substance absorbs
(5)
The color of potassium permanganate solution is due to
[A]
n→π *
[B]
π→π *
[C]
d →d*
[D]
n→s*
(6)
Which of the following detector has fast response time
[A]
Photomultiplier tube
[B]
Photo tube
[C]
photo diode array
[D]
Barrier layer cell
Answer: photo diode array
(7)
The light which reaches the detector without passing through the cell is known as
[A]
Dark radiation
[B]
Stray radiation
[C]
Photoluminescence
[D]
Chemiluminescence
(8)
A sample exhibited has an absorbance 1.0 in UV-Visble spectroscopy. the percentage transmittance will be
[A]
1%n
[B]
0.1%
[C]
10%
[D]
0.01%
(9)
In phototube, photo multiplier tube, the transmitted light from the cells produces photocurrent by falling on
[A]
Photocathode
[B]
Photoanode
[C]
Metal junction
[D]
Metal layer
(10)
The absorptivity of a standard sample of 1% w/v solution measured at a path length of 1 cm, A(1%, 1 cm), is 312 at 254 nm. The absorbance of the test sample was observed 0.624 at 254 nm. The concentration of test sample is
[A]
5 g/100ml
[B]
5 mg/100 ml
[C]
2 g/100ml
[D]
2mg/100 ml
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