BD Marine Cadet Admission cheat sheet

Subject-verb agreement: a singular subject takes a singular verb; compound subjects joined by 'and' take a plural verb unless they form one idea.

Tense sequence: past main clause usually takes past or past perfect in the subordinate clause; present main clause allows any tense.

Active to passive: move object to subject, use correct form of 'be' plus past participle, and add 'by' only when the agent matters.

Articles: use 'a/an' for one of many, 'the' for a specific or previously mentioned noun, and no article for general plurals or abstract nouns.

Prepositions of time: 'at' for clock times, 'on' for days and dates, 'in' for months, years, and long periods.

Direct to indirect speech: shift tense back one step, change pronouns to the speaker's viewpoint, and adjust time words such as 'now' to 'then'.

Modals: 'can' shows ability, 'may' shows permission or possibility, 'must' shows obligation, 'should' shows advice; never add 'to' after a modal.

Conditionals: first conditional uses present plus 'will'; second uses past plus 'would'; third uses past perfect plus 'would have'.

Common error pairs: 'affect' (verb) versus 'effect' (noun); 'its' (possessive) versus 'it's' (it is); 'fewer' for count nouns, 'less' for mass nouns.

Quadratic formula: for ax^2+bx+c=0, x = [-b ± sqrt(b^2-4ac)] / 2a; the discriminant b^2-4ac decides two, one, or no real roots.

Arithmetic progression: nth term a+(n-1)d; sum of n terms = (n/2)[2a+(n-1)d].

Geometric progression: nth term a*r^(n-1); sum of n terms = a(r^n-1)/(r-1) for r not equal to 1.

Trigonometric identities: sin^2 x + cos^2 x = 1; 1 + tan^2 x = sec^2 x; sin 2x = 2 sin x cos x.

Sine rule: a/sin A = b/sin B = c/sin C; cosine rule: a^2 = b^2 + c^2 - 2bc cos A.

Logarithms: log(ab)=log a + log b; log(a/b)=log a - log b; log(a^n)=n log a; log base b of b equals 1.

Mensuration: circle area pir^2 and circumference 2pir; sphere volume (4/3)pir^3 and surface 4pir^2; cylinder volume pir^2h.

Speed, distance, time: distance = speed x time; average speed = total distance divided by total time, not the mean of the speeds.

Probability of an event = favourable outcomes divided by total equally likely outcomes; the sum of all probabilities equals 1.

Newton's second law: F = ma; the net force in newtons equals mass in kilograms times acceleration in m/s^2.

Kinematics: v = u + at; s = ut + (1/2)at^2; v^2 = u^2 + 2as, where u is initial and v is final velocity.

Work and energy: work = force x displacement along the force; kinetic energy = (1/2)mv^2; gravitational potential energy = mgh.

Ohm's law: V = IR; power P = VI = I^2R = V^2/R; resistors in series add, in parallel the reciprocals add.

Archimedes' principle: buoyant force equals the weight of fluid displaced; a floating body displaces its own weight of fluid.

Pressure in a fluid: P = rhogh; it increases with depth and does not depend on the shape of the container.

Wave relation: speed = frequency x wavelength; light in vacuum travels about 3 x 10^8 m/s.

Heat: Q = mc(delta T) for temperature change and Q = mL for a change of state, where L is latent heat.

Mole concept: one mole contains 6.022 x 10^23 particles; moles = mass in grams divided by molar mass.

Gas laws: PV = nRT with R about 8.314 J/(mol*K); at STP one mole of ideal gas occupies about 22.4 L.

pH scale: pH = -log[H+]; pH below 7 is acidic, 7 is neutral, above 7 is basic at 25 degrees Celsius.

Acid-base neutralisation: acid + base gives salt + water; H+ plus OH- gives H2O.

Oxidation is loss of electrons and increase in oxidation number; reduction is gain of electrons and decrease in oxidation number.

Periodic trends: atomic radius decreases across a period and increases down a group; electronegativity rises across a period and falls down a group.

Balancing equations: the number of atoms of each element must be equal on both sides; coefficients only, never subscripts, are changed.

Molarity = moles of solute divided by volume of solution in litres; dilution follows M1V1 = M2V2.

Common salts: sodium chloride is table salt; calcium carbonate is limestone and chalk; sodium bicarbonate is baking soda.

The International Maritime Organization (IMO) is the UN agency for shipping safety and pollution prevention; it is headquartered in London.

SOLAS, MARPOL, STCW, and MLC are core IMO conventions covering safety, pollution, training, and seafarers' working conditions.

The United Nations has 193 member states; its principal organs include the General Assembly and Security Council.

India's coastline runs about 7,500 km including islands; major ports include Mumbai, Chennai, Kolkata, and Visakhapatnam.

The Suez Canal links the Mediterranean and Red Seas; the Panama Canal links the Atlantic and Pacific Oceans.

Latitude lines run east-west and measure north-south position; longitude lines run pole to pole and define time zones.

A nautical mile is about 1,852 metres, equal to one minute of latitude; a knot is one nautical mile per hour.

Current affairs must be verified against recent official sources, since facts such as office holders change frequently.

Body mass index = weight in kilograms divided by height in metres squared; 18.5 to 24.9 is the normal adult range.

Normal resting adult pulse is about 60 to 100 beats per minute; trained individuals often sit at the lower end.

Normal adult resting blood pressure is about 120/80 mmHg; readings of 140/90 or above indicate hypertension.

Visual acuity is commonly tested with a Snellen chart at 6 metres; 6/6 vision is normal.

Colour vision is screened with Ishihara plates; normal colour vision is required for most deck and engine watchkeeping roles.

Distance visual acuity standards for seafarers generally require correction to at least 6/6 in the better eye and 6/9 in the other.

Hearing is assessed by audiometry; significant hearing loss can disqualify a candidate from watchkeeping duties.

Haemoglobin reference ranges are roughly 13 to 17 g/dL for men and 12 to 15 g/dL for women; low values suggest anaemia.