Question at position 11 Humans are warned to shield their eyes from ultraviolet radiation with wavelengths shorter than 300 nm but not from infrared radiation with wavelengths of about 900 nm. Which of the following explains the reason for this based on what happens at the molecular level with exposure to these types of radiation?300 nm radiation has one-third the energy of 900 nm radiation, so ultraviolet radiation is more likely to cause molecular vibration to occur.300 nm radiation has triple the energy of 900 nm radiation, so ultraviolet radiation is more likely to promote electrons or break covalent bonds.900 nm radiation has one-third the energy of 300 nm radiation, so infrared radiation is more likely to cause molecular rotation to occur.900 nm radiation has triple the energy of 300 nm radiation, so infrared radiation is more likely to promote electrons to break covalent bonds.

Question

BlackTom AI · Accepted Answer

The question asks why shielding from UV (∼300 nm) is more critical than shielding from near-IR (∼900 nm) based on molecular interactions with the radiation.
Option 1: '300 nm radiation has one-third the energy of 900 nm radiation, so ultraviolet radiation is more likely to cause molecular vibration to occur.' This is incorrect because shorter wavelengths have higher energy per photon, not lower. If 300 nm had one-third the energy, it would be less able to drive high-energy processes like bond breaking, which contradicts what photons from UV can do. Additionally, molecular vibration typically involves lower-energy transitions compared to electronic excitations, so this statement mischaracterizes the energy scale involved.
Option 2: '300 nm radiation has triple the energy of 900 nm radiation, so ultraviolet radiation is more likely to promote electrons or break covalent bonds.' This aligns with the fundamental relation E = hν ≈ hc/λ, where shorter λ means higher photon energy. Ultraviolet photons have enough energy to promote electrons to higher electronic states or to overcome covalent bond energies, leading to bond breakage or other photochemical effects. This explains why UV can cause damaging electronic transitions and bond disruption.
Option 3: '900 nm radiation has one-third the energy of 300 nm radiation, so infrared radiation is more likely to cause molecular rotation to occur.' While it is true that 900 nm photons have less energy than 300 nm photons, the claim that infrared radiation is more likely to cause molecular rotation than electronic transitions is misleading. Infrared photons are indeed associated with rotational and some vibrational transitions, but the assertion that 900 nm (which is still relatively low energy compared to IR bands) would mainly cause rotation oversimplifies and misplaces the energy comparison for this wavelength range. Moreover, 900 nm is not typically the primary driver of rotational transitions in most molecules relative to the well-established infrared range.
Option 4: '900 nm radiation has triple the energy of 300 nm radiation, so infrared radiation is more likely to promote electrons to break covalent bonds.' This is the opposite of the fundamental energy-wavelength relationship. A 900 nm photon has far less energy than a 300 nm photon, not triple. Therefore this statement is false because it assigns much higher energy to 900 nm radiation than it actually has and incorrectly predicts electronic bond-breaking effects for infrared wavelengths.
In summary, the key concept is that photon energy scales inversely with wavelength: shorter wavelengths carry more energy, enabling electronic excitations and bond-breaking processes that are not typically accessible at the longer wavelengths of infrared light. The option that correctly captures this energy relationship and its chemical consequence is the one stating that 300 nm radiation has triple the energy of 900 nm radiation, leading to electronic excitation or covalent bond disruption.

View Explanation

Log in for full answers

Similar Questions

Which of the following processes only occur upon absorption of a high energy photons (photons with energy greater than visible light)?

In a consumer society, many adults channel creativity into buying things

Economic stress and unpredictable times have resulted in a booming industry for self-help products

People born without creativity never can develop it

A product has a selling price of $20, a contribution margin ratio of 40% and fixed cost of $120,000. To make a profit of $30,000. The number of units that must be sold is: Type the number without $ and a comma. Eg: 20000

Which of the following statement regarding cost is correct:

Under the assumptions used in cost-volume-profit analysis, as the activity increases:

The CVP and break-even analysis are supported by a range of important assumptions. Which of the following is not an assumption of the CVP:

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler