UPSC-CMS 2013 - Community Medicine Practice Questions

Q: Horrock's apparatus is used to measure :

Free chlorine. ***Free chlorine*** - Horrock's apparatus is a device specifically designed for the **estimation of residual free chlorine** in treated water. - It uses a tablet and a comparator system to visually match the color produced with a standard scale, indicating the free chlorine level. *Free and combined chlorine* - This apparatus is specifically designed for **free chlorine** and does not directly measure combined chlorine. - While total chlorine (free + combined) can be inferred through subsequent tests, the Horrock's apparatus itself isolates free chlorine. *Chlorine demand* - **Chlorine demand** refers to the amount of chlorine used up by impurities in water before a residual begins to form, and is not directly measured by Horrock's apparatus. - It is determined by knowing the added chlorine dose and the residual chlorine remaining after a contact period. *Combined chlorine* - **Combined chlorine** refers to chlorine that has reacted with ammonia or organic nitrogen compounds, forming chloramines, and is not the primary measurement of Horrock's apparatus. - Measuring combined chlorine typically involves different methods or calculations after determining free and total chlorine.

Q: Diethyltoluamide is an effective :

Repellent. ***Repellent*** - **Diethyltoluamide (DEET)** is a highly effective and widely used **insect repellent**. - It works by creating an olfactory barrier that deters mosquitoes and other biting insects. *Agent against propagation of Anopheles* - While DEET can prevent bites from **Anopheles mosquitoes**, it doesn't directly target their reproduction or population growth. - Measures against propagation typically involve **larvicides**, habitat modification, or insecticidal spraying. *Space spray* - **Space sprays** are designed to kill insects in an area, often using insecticides like pyrethroids, rather than repelling them from an individual. - DEET's mechanism is to deter insects from landing on skin or clothing, not to kill them in an open space. *Larvicide* - **Larvicides** are chemical or biological agents used to kill insect larvae, particularly mosquito larvae, in aquatic breeding sites. - DEET is applied to the skin or clothing to prevent adult insect bites and does not act on larvae.

Question 1

Horrock's apparatus is used to measure :

Accepted Answer

Free chlorine

Answer

Free and combined chlorine

Answer

Chlorine demand

Answer

Combined chlorine

Question 2

The order of priority of immunization strategy to prevent congenital rubella infection from first to last is :

Accepted Answer

Infants → children 1-14 years → women of reproductive age group

Answer

Women of reproductive age group → children 1-14 years → Infants

Answer

Infants → women of reproductive age group → children 1-14 years

Answer

Women of reproductive age group → Infants → children 1-14 years

Question 3

Diethyltoluamide is an effective :

Accepted Answer

Repellent

Answer

Agent against propagation of Anopheles

Answer

Space spray

Answer

Larvicide

UPSC-CMS 2013 — Community Medicine