NPCIL Scientific Assistant flashcards

34 cards. Read the term and the definition here. The deck at the top of this page is optional.

Newton's Second Law

The net force on an object equals its mass times acceleration (F = ma). It links force, mass, and acceleration in classical mechanics.

Photoelectric Effect

Emission of electrons from a metal surface when light of frequency above a threshold strikes it. Energy of photon hf equals work function plus kinetic energy.

Half-Life

Time required for half the atoms in a radioactive sample to decay. After n half-lives, remaining fraction is (1/2)^n.

Ohm's Law

Current through a conductor is directly proportional to voltage across it, at constant temperature: V = IR, where R is resistance.

Mole Concept

One mole contains 6.022×10²³ particles (Avogadro's number). Molar mass in grams equals mass of one mole of substance.

pH Scale

Measure of hydrogen ion concentration: pH = −log[H⁺]. Values below 7 are acidic, above 7 basic, and 7 neutral at 25 °C.

Le Chatelier's Principle

When a system at equilibrium is disturbed, it shifts to counteract the change. Increasing pressure favors side with fewer gas moles.

Molarity

Concentration expressed as moles of solute per liter of solution. Unit is mol/L (M). Temperature changes affect molarity due to volume expansion.

Quadratic Formula

Roots of ax² + bx + c = 0 are x = [−b ± √(b² − 4ac)]/(2a). Discriminant b² − 4ac determines real, equal, or complex roots.

Sum of AP

Sum of first n terms of arithmetic progression with first term a and common difference d: S_n = n/2 [2a + (n−1)d].

Derivative of xⁿ

For any real n, d/dx(xⁿ) = n xⁿ⁻¹. This power rule is fundamental in differential calculus.

Binomial Theorem

Expansion (a+b)ⁿ = Σ C(n,k) aⁿ⁻ᵏ bᵏ for k = 0 to n, where C(n,k) is the binomial coefficient n!/(k!(n−k)!).

Subject-Verb Agreement

A singular subject takes a singular verb; a plural subject takes a plural verb. Phrases between subject and verb do not change agreement.

Active vs Passive Voice

Active voice: subject performs action. Passive voice: object becomes subject and verb becomes be + past participle, often with 'by' agent.

Direct to Indirect Speech

Convert quoted speech to reported speech by changing pronouns, backshifting tense, and adjusting time/place words (now → then, here → there).

Comprehension Main Idea

The central point the passage conveys. Identify it by looking at topic sentences, repeated concepts, and the conclusion rather than isolated details.

Fundamental Rights

Guaranteed in Part III of Indian Constitution (Articles 12–35). Include equality, freedom, against exploitation, religion, cultural, and constitutional remedies.

NPCIL

Nuclear Power Corporation of India Limited, incorporated in 1987. A Government of India enterprise under DAE that operates India's nuclear power reactors.

Three-Stage Nuclear Programme

India's strategy: Stage 1 PHWRs on natural uranium; Stage 2 fast breeder reactors using plutonium; Stage 3 thorium-based reactors for long-term energy security.

IAEA Safeguards

Verification measures by the International Atomic Energy Agency to ensure nuclear material is not diverted from peaceful uses. India has an Additional Protocol.

Paris Agreement

2015 international treaty to limit global warming to well below 2 °C, preferably 1.5 °C, above pre-industrial levels. India targets net-zero by 2070.

AERB

Atomic Energy Regulatory Board of India, headquartered in Mumbai. It regulates nuclear and radiation safety and issues safety codes and licences.

Syllogism

Logical reasoning with categorical statements. Use Venn diagrams; 'All A are B' does not imply 'All B are A'. 'Some' means at least one.

Blood Relations

Reasoning questions about family relationships. Draw a family tree with vertical lines for generations and horizontal lines for siblings or spouses.

Coding-Decoding

Letter positions A=1 to Z=26. Reverse position = 27 − position. Apply consistent shift or pattern to decode words.

Simple Interest

Interest calculated only on principal: SI = PRT/100, where P is principal, R is annual rate percent, and T is time in years.

Average Speed

Total distance divided by total time. It is not the arithmetic mean of speeds unless equal distances are traveled at each speed.

Permutation and Combination

nPr = n!/(n−r)! gives arrangements; nCr = n!/(r!(n−r)!) gives selections. Order matters in permutations, not in combinations.

RAM vs ROM

RAM is volatile working memory that loses data on power off. ROM is non-volatile and stores firmware such as BIOS permanently.

IP Address

Unique numerical label assigned to devices on a network. IPv4 is 32-bit; IPv6 is 128-bit. DNS resolves domain names to IP addresses.

ALARA Principle

As Low As Reasonably Achievable: minimize radiation dose considering economic and social factors. Applied through time, distance, and shielding.

Dose Limits

ICRP/IAEA occupational limit: 20 mSv/year averaged over 5 years, max 50 mSv in one year. Public limit is 1 mSv/year.

Nuclear Fission

Splitting of a heavy nucleus such as U-235 into lighter nuclei, releasing energy and 2–3 neutrons. Sustained chain reaction requires k ≥ 1.

Defence-in-Depth

Nuclear safety philosophy using multiple independent barriers (fuel cladding, pressure boundary, containment) to prevent release of radioactive material.