DCOA Mixed Practice Test #643

Question 1

A scientist is designing a radiation detector to specifically identify alpha particles emitted from a radioactive source, while minimizing interference from beta and gamma radiation. Which of the following detector characteristics would be most effective for this purpose?

Accepted Answer

B. A very thin window or no window, and a short detection path within the detector. — Alpha particles have very low penetrating power and a short range in matter. Therefore, a detector with a very thin window or no window allows them to enter, and a short detection path is sufficient to capture their energy before they are fully absorbed, effectively distinguishing them from more penetrating beta and gamma radiation. Thick lead shielding is primarily for gamma rays, liquid scintillators are general-purpose but less specific for alpha due to range, and a magnetic field deflects both alpha and beta particles without selective identification based on entry alone.

Answer

A. A thick lead shielding around the detector.

Answer

C. A high-density liquid scintillator.

Answer

D. A strong magnetic field across the detection area.

Question 2

A concave lens is:‌​‍

Accepted Answer

Diverging — Concave lens makes parallel rays diverge; used for short-sightedness.‌​‍

Answer

Plano

Answer

Converging

Answer

Cylindrical

Question 3

Jewish Synagogue in Kochi built in:‌​‍

Accepted Answer

1568 — Paradesi Synagogue in Mattancherry, Kochi — built 1568.‌​‍

Answer

1468

Answer

1768

Answer

1668

Question 4

Caste system is a form of:‌​‍

Accepted Answer

Closed stratification (birth-based) — Caste = closed, ascribed status by birth, endogamy, hereditary occupation, hierarchy based on purity/pollution. ‌​‍Unique to Indian subcontinent.

Answer

Open stratification

Answer

Meritocracy

Answer

Class

Question 5

Which was the first European power to lose a naval battle to an Indian ruler?‌​‍

Accepted Answer

Dutch to Travancore — At Colachel (1741), Marthandavarma's Travancore navy defeated the Dutch — the first European defeat to an Indian ruler.‌​‍

Answer

French to Mysore

Answer

Portuguese to Zamorin

Answer

British to Marathas

Question 6

Make in India initiative was launched on:‌​‍

Accepted Answer

25 September 2014 — Make in India was launched on 25 September 2014 to encourage manufacturing in India.‌​‍

Answer

2 October 2014

Answer

15 August 2014

Answer

26 January 2015

Question 7

Which of the following is a major Phase II metabolic reaction where a highly polar endogenous molecule is attached to a drug or its Phase I metabolite, primarily to increase water solubility and facilitate its excretion?

Accepted Answer

D. Glucuronidation — Glucuronidation is a prominent Phase II conjugation reaction where glucuronic acid is attached to a drug, significantly increasing its polarity and molecular weight, thus facilitating its excretion, primarily via the kidneys. Oxidation, reduction, and hydrolysis are typically Phase I reactions that introduce or expose polar functional groups.

Answer

A. Oxidation

Answer

B. Reduction

Answer

C. Hydrolysis

Question 8

Which part of the nephron is primarily responsible for the reabsorption of most filtered water, electrolytes, and nutrients back into the bloodstream?

Accepted Answer

D. Proximal convoluted tubule — The proximal convoluted tubule (PCT) is where the majority (approximately 65-70%) of filtered water, sodium, chloride, potassium, glucose, and amino acids are reabsorbed back into the bloodstream. The glomerulus is responsible for filtration, the Loop of Henle primarily concentrates urine, and the distal convoluted tubule fine-tunes reabsorption and secretion.

Answer

A. Glomerulus

Answer

B. Loop of Henle

Answer

C. Distal convoluted tubule

Question 9

NPCI stands for:‌​‍

Accepted Answer

National Payment Corporation of India — National Payments Corporation of India — operates UPI, RuPay, etc.‌​‍

Answer

New Payment Corporation of India

Answer

National Pay Commission of India

Answer

National Payments Council of India

Question 10

Bronze is an alloy of:

Accepted Answer

Cu + Sn — Bronze ≈ 88% copper + 12% tin; used for statues, bearings.

Answer

Cu + Zn

Answer

Cu + Al

Answer

Fe + Ni

DCOA Mixed Practice Test #643