SRMHCAT flashcards

32 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 a body equals mass times acceleration (F = ma). Force and acceleration point in the same direction, and zero net force means constant velocity.

Projectile maximum range

For a projectile launched and landing at the same height, range R = u²sin2θ/g, which is greatest at a launch angle of 45 degrees.

Work-energy theorem

The net work done on a body equals its change in kinetic energy. It lets you solve problems without tracking time, using only initial and final speeds.

Series and parallel resistors

In series, resistances add directly and current is common. In parallel, the reciprocals add and voltage is common, so total resistance is less than the smallest branch.

Photoelectric threshold

Electrons are ejected only when incident light frequency exceeds the threshold value equal to work function divided by Planck's constant; intensity affects count, not maximum energy.

Mole and Avogadro number

One mole contains 6.022×10²³ particles and equals the molar mass in grams. It converts between mass, particle count, and gas volume at standard conditions.

Molarity versus molality

Molarity is moles of solute per litre of solution and varies with temperature. Molality is moles per kilogram of solvent and stays fixed with temperature changes.

Le Chatelier's principle

When a system at equilibrium is disturbed by concentration, pressure, or temperature change, it shifts in the direction that partly opposes the disturbance.

Oxidation number rules

Elements in free state are zero; oxygen is usually −2, hydrogen +1; the sum of oxidation numbers equals the overall charge of the species.

Hybridisation by steric number

Steric number counts bonded atoms plus lone pairs on the central atom: two gives sp, three sp², four sp³, five sp³d, and six sp³d² geometry.

pH scale

pH equals the negative logarithm of hydrogen ion concentration. Values below 7 are acidic, above 7 basic, and each unit represents a tenfold concentration change.

Transcription versus translation

Transcription copies DNA into messenger RNA in the nucleus. Translation reads mRNA codons at ribosomes to assemble amino acids into a polypeptide chain.

Mitosis versus meiosis

Mitosis produces two genetically identical diploid cells for growth. Meiosis produces four haploid gametes with genetic recombination through crossing over and independent assortment.

Calvin cycle

The light-independent stage in the chloroplast stroma where RuBisCO fixes carbon dioxide, using ATP and NADPH from the light reactions to build sugars.

Enzyme kinetics basics

Enzymes lower activation energy and are unchanged after reaction. Rate increases with substrate and temperature up to an optimum, then falls as the enzyme denatures.

Mendelian dihybrid ratio

Crossing two heterozygotes for two independently assorting genes gives a 9:3:3:1 phenotypic ratio in the offspring generation, assuming complete dominance.

Nephron reabsorption

Most glucose, amino acids, and water are reabsorbed in the proximal convoluted tubule; the loop of Henle builds the medullary osmotic gradient for concentrating urine.

Blood group antigens

AB blood carries both A and B antigens and accepts all ABO types; O blood has no antigens and is the universal donor; plasma antibodies follow the opposite pattern.

Compound interest formula

Amount equals principal times one plus rate over 100, raised to the number of years. Compound interest is the amount minus the principal.

Average speed for equal distances

When equal distances are covered at speeds x and y, average speed is 2xy divided by x plus y, which is the harmonic mean, not the arithmetic mean.

Combined work formula

If A finishes a job in a days and B in b days, working together they finish in ab divided by a plus b days, provided their rates simply add.

Permutation versus combination

Permutations count ordered arrangements and use nPr. Combinations count unordered selections and use nCr, which equals nPr divided by r factorial.

Successive percentage change

Two successive changes of a and b percent produce a net change of a plus b plus ab over 100 percent, so a 20 percent rise then fall is a 4 percent net fall.

Syllogism validity rule

A conclusion is valid only if it holds in every possible arrangement of the premises. A single counterexample diagram makes the conclusion invalid.

Alligation rule

Alligation finds the ratio for mixing two items of different values to reach a mean: ratio equals the differences between each value and the mean, taken crosswise.

Relative speed

For bodies moving in opposite directions, relative speed is the sum of speeds; in the same direction it is the difference, used for train and boat problems.

Dimensional analysis check

Every term in a valid physical equation must have identical dimensions. Checking dimensions quickly rejects wrong formulas and catches unit conversion errors.

Negative marking strategy

With a penalty of one quarter mark per wrong answer, random guessing among four options is break-even; guessing pays only when at least two options are eliminated.

Order of magnitude estimate

Round inputs to one significant figure before computing multiple-choice numericals. This exposes answers that are off by factors of ten or wrong units.

Standard conditions reminder

Gas volume 22.4 litres per mole and pH neutral at 7 both assume 273 K and 1 atm. Changing temperature or pressure changes these reference values.

Data interpretation base value

Percentage change is always computed relative to the original or earlier value, not the later one, and axis scales must be read before comparing heights.

Diagram-first reasoning

For seating, direction, and blood-relation puzzles, sketch positions or family links on paper before testing options; this prevents contradictions accumulating silently.