Electromagnetic radiation consists of discrete packets of energy which are called:

A photon consists of an oscillating electric field (E) and an oscillating magnetic field (M) which are _______ to each other.

According to MOT, in molecules, atomic orbitals combine to form _______ which surround the molecule.

Molecular bonds have _______ potential energy than in separate atomic orbitals.

Electrons prefer to stay in a molecular bond according to MOT.

Refer to the diagram showing the electromagnetic wave. What are the two fields shown as oscillating and perpendicular to each other?

Refer to the molecular orbital diagram. Which orbital has lower energy?

What is the principle of UV-Visible Spectrometer based on?

Spectrum is a graph of intensity of absorbed or emitted radiation by sample versus ______ or wavelength (λ).

A spectrometer is an instrument designed to measure the spectrum of a ______.

The absorption of light by any absorbing material is governed by which two laws?

Who suggested the Bouger-Lambert law in 1729?

Bouger-Lambert law is often attributed to which scientist?

According to Bouger-Lambert law, the amount of light absorbed is proportional to the thickness of the absorbing material and is independent of the intensity of the incident light.

Absorption Spectroscopy is an analytical technique which concerns with the measurement of absorption of ______ radiation.

The UV radiation region extends from ______ nm to ______ nm.

The common solvent used for preparing sample to be analyzed in absorption spectroscopy is either ______ or ______.

What does Beer’s Law state about the amount of light absorbed by a material?

Write the equation for Beer Lambert’s Law and define each term:

Which of the following is NOT a limitation of Beer’s Law?

Beer’s Law is rigorously obeyed provided a single species gives rise to the observed absorption.

Fill in the blank: At room temperature, molecules are in the lowest energy levels, denoted as _____

What is the energy difference (ΔE) when a molecule absorbs UV-visible light and an electron is promoted to a higher energy state?

List one condition under which Beer’s Law may not be obeyed.

Which of the following is NOT a possible electronic transition?

Fill in the blank: The energy required for a σ → σ* transition is _______.

Methane (CH₄) has only C-H bonds and can undergo which type of electronic transition?

Compounds containing multiple bonds like alkenes, alkynes, carbonyl, nitriles, and aromatic compounds undergo π → π* transitions.

Alkenes generally absorb in which region?

Which atoms in saturated compounds are capable of n → σ* transition?

n → σ* transitions usually require more energy than σ → σ* transitions.

The number of organic functional groups with n → σ* peaks in UV region is small. What is the range of these peaks?

What happens during an n → π* transition?

Compounds containing which types of double bonds involving hetero atoms undergo n → π* transitions?

n → π* transitions require minimum energy and show absorption at longer wavelength around ______ nm.

Are σ → π* and π → σ* transitions forbidden or allowed electronic transitions?

Which electronic transitions show absorption in the region above 200 nm accessible to UV-visible spectrophotometer?

Refer to the diagram titled 'The possible electronic transitions can graphically shown as:' and identify which transition requires the highest energy.

What is the process called when a molecule absorbs energy and transitions from the ground state (S0) to an excited singlet state (S1 or S2)?

Refer to the Jablonski Energy Diagram (Figure 1). Fill in the blank: The process where a molecule returns from an excited singlet state (S1) to the ground state (S0) by emitting a photon is called _________.

Refer to the Jablonski Energy Diagram (Figure 1). Which process occurs on the timescale of $$10^{-3} to 10^{2}$$ seconds?

Intersystem crossing is a process where a molecule transitions from an excited singlet state to an excited triplet state.

Which of the following is NOT a component of a UV-Visible spectrophotometer?

Fill in the blank: The five basic optical instrument components are Source, Wavelength Selector, Sample Container, Detector/Photoelectric Transducer, and _________

Which of the following is a UV radiation source?

Mercury arc lamp is a source of UV radiation.

Fill in the blank: The three sources of visible radiation are Tungsten lamp, Mercury vapour lamp, and _________

Which of the following is NOT a UV radiation source?

Wavelength selectors output a limited, narrow, continuous group of wavelengths called a _______.

What are the two types of wavelength selectors?

What is the function of a monochromator in spectroscopy?

Monochromators are used in most scanning spectrometers including UV, visible, and IR instruments.

Which of the following is NOT a type of prism used in monochromators?

Fill in the blank: The two types of grating used in monochromators are _______ type and transmission type.

Spectroscopy requires all materials in the beam path other than the analyte to be as _______ to the radiation as possible.

Which material can be used for sample cuvettes in the wavelength range 220 - 3800 nm?

Refer to the diagram of a single beam spectrophotometer. Which component is responsible for separating polychromatic light into a narrow band of wavelength?

In a single beam spectrophotometer, the transmitted intensity after the sample is measured by the _______.

In a single beam instrument, the light beam follows a single path from the source, to the monochromator, to the sample cell, and finally to the detector.

Which of the following statements is true about continuous sources used in UV-Vis Spectrophotometers?

Sources of radiation should be ______ and of high intensity.

Which lamp is used for visible and near IR radiation?

The Deuterium Lamp is used for ______ radiation and covers the wavelength range of 200-400 nm.

Ideally, the output of a wavelength selector would be a radiation of a ________ wavelength.

No real wavelength selector is ideal, usually a ________ of radiation is obtained.

The ________ this bandwidth is, the better performance of the instrument.

Which of the following are types of wavelength selectors?

Filters permit certain ________ (bandwidth of ~ 50 nm) to pass through. Fill in the blank.

The simplest kind of filter is ________, the most common of this type of filters is ________. Fill in the blanks.

Filters are used in which region?

What does colored glass absorb and transmit?

Which of the following is NOT a disadvantage of colored glass filters?

Colored glass filters are very good wavelength selectors and can be used in instruments utilized in research.

Why do colored glass filters give a chance for deviations from Beer’s law?

What is the primary use of monochromators?

Monochromators can be used for which region?

All monochromators are similar in mechanical construction.

Fill in the blank: All monochromators employ ________, mirrors, lenses, gratings or prisms.

What is the function of the concave mirrors in a reflection grating monochromator?

In a reflection grating monochromator, what happens when rays fall on the reflection grating?

Which component in the reflection grating monochromator is responsible for dispersing the light?

The orientation of the reflection grating directs only one narrow band wavelength to the exit slit of the monochromator.

1. The reflection grating is ruled with a series of closely spaced, parallel grooves with repeated distance ____.

The grating is covered with ____ to make it reflective.

When polychromatic light is reflected from the grating, each groove behaves as ____ of radiation.

When adjacent light rays are in phase, they reinforce one another. This is called ____.

When adjacent light rays are not in phase, they partially or completely cancel one another. This is called ____.

What is the Echelette Grating equation as shown in the image?

According to the image, what is observed for each reflection angle θr?