66. The compound used to calibrate absorbance scale of the UV-visible instrument is
(A) HCl
(B) K2Cr2O7
(C) KCl
(D) KMnO 4
67. The units for absorbance are
(A) L mol -1 cm -1
(B) g mol -1 cm -1
(C) Mol. L -1.cm =1
(D) None of the above
68. At cut-off wavelength the absorbance of the solvent is
(A) 0
(B) 0.5
(C) 1
(D) 2
69. The lmax in first derivative curve of UV spectra is denoted by slope value as
(A) 1
(B) 0
(C) -1
(D) Maximum
70. Dynodes are present in
(A) Barrier layer detector
(B) Phototube
(C) Photomultiplier tube
(D) Diode array