DRDO CEPTAM STA-B flashcards

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

Sum of first n odd numbers

The sum of the first n odd natural numbers 1 + 3 + 5 + … equals n squared. For example, 1 + 3 + 5 + 7 = 16, which is 4².

Letter position reverse value

In the English alphabet each letter's reverse value is 27 minus its forward position, so A = 26 and Z = 1. This is used in coding-decoding and alphabet series questions.

Only son of my mother

If a man says a photograph shows the only son of his mother, he is referring to himself, because his mother has exactly one son. Always draw a family tree first.

Right turn effect on facing

A right turn rotates the direction of facing by 90 degrees clockwise, so two right turns amount to a 180-degree turn, the opposite direction. A left turn is anticlockwise.

Mirror image of clock time

The mirror-image time of a clock showing h:m is found as 11:60 minus the given time, so a clock at 3:10 appears in a mirror as 8:50.

Ranking total formula

If a person is nth from the left end and mth from the right end of a row, the total number of persons is n + m − 1, provided both counts belong to the same row.

Syllogism: All A are B

From 'All A are B' and 'All B are C' it follows that 'All A are C'. 'All A are B' combined with 'No B is C' gives 'No A is C'.

DRDO founding year

The Defence Research and Development Organisation was formed in 1958 by merging the Defence Science Organisation with the Technical Development Establishment. Its motto is 'Balasya Mulam Vigyanam'.

Param Vir Chakra

It is India's highest wartime gallantry award, given for the most conspicuous bravery or self-sacrifice in the presence of the enemy. It was instituted in 1950.

BrahMos joint venture

BrahMos is a supersonic cruise missile developed by a joint venture between India's DRDO and Russia's NPO Mashinostroyeniya. It is named after the Brahmaputra and Moskva rivers.

Bharat Ratna

It is the highest civilian award of India, conferred for exceptional service in art, literature, science and public affairs. Instituted in 1954, it is an award and not a title.

ISRO formation date

The Indian Space Research Organisation was formed on 15 August 1969, succeeding INCOSPAR, with Vikram Sarabhai as its guiding founder. Its headquarters is in Bengaluru.

Article 32 of Constitution

Article 32 gives citizens the right to move the Supreme Court directly for enforcement of Fundamental Rights. Dr Ambedkar called it the heart and soul of the Constitution.

RBI established

The Reserve Bank of India began operations in 1935 under the RBI Act 1934 and was nationalised in 1949. It conducts monetary policy and issues all notes except the one-rupee note.

Simple interest formula

Simple interest is SI = P × R × T / 100, where P is the principal, R the annual rate in percent and T the time in years. It is charged only on the principal.

CI − SI for two years

For two years at R percent, compound interest exceeds simple interest by P(R/100)², where P is the principal. This shortcut avoids computing both interest values separately.

Equal rise and fall effect

If a quantity rises by x percent and then falls by x percent, the net change is a decrease of x²/100 percent, independent of the original value.

km/h to m/s conversion

Multiply a speed in kilometres per hour by 5/18 to convert it into metres per second; multiply by 18/5 to convert metres per second back into kilometres per hour.

Two workers together formula

If A alone finishes a job in a days and B alone in b days, then working together they finish it in ab/(a + b) days, since their one-day efficiencies add.

HCF and LCM product rule

For two positive integers, HCF × LCM equals the product of the two numbers. This lets you find the LCM once the HCF is known, and the reverse.

Average of first n naturals

The average of the first n natural numbers 1, 2, …, n is (n + 1)/2. For any arithmetic progression the average equals the mean of the first and last terms.

Ohm's law

At constant temperature the current through a conductor is directly proportional to the potential difference across it, so V = IR, where R is the resistance in ohms.

SI unit of force

The SI unit of force is the newton (N), defined as the force that gives a mass of one kilogram an acceleration of one metre per second squared.

pH scale range

pH measures hydrogen-ion concentration on a scale from 0 to 14. A value below 7 is acidic, 7 is neutral and above 7 is basic, with each unit a tenfold change.

Universal donor blood group

O-negative red blood cells are the universal donor because they carry neither A nor B nor Rh antigens, so they can be transfused to any ABO or Rh group.

Chemical formula of baking soda

Baking soda is sodium bicarbonate, NaHCO₃. On heating it releases carbon dioxide, which is why it is used as a leavening agent in cooking and baking.

Photosynthesis balanced equation

Six molecules of carbon dioxide and six of water, using light energy and chlorophyll, produce one glucose molecule and six oxygen molecules: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.

Subject-verb agreement with 'each'

The words each, every, either, neither, everyone and nobody are singular, so they take a singular verb, as in 'Each of the boys is present'.

Affect versus effect

'Affect' is usually a verb meaning to influence, while 'effect' is usually a noun meaning a result, as in 'the rain affected the match; the effect was a draw'.

Idiom: bite the bullet

To bite the bullet means to endure a painful or difficult situation bravely instead of avoiding it. It works as a verb phrase inside a sentence.

Active to passive voice rule

The object of the active sentence becomes the subject, the verb becomes a form of 'be' plus the past participle, and the original subject follows 'by'.

Since versus for

'Since' is used with a point of time, as in since 2010 or since Monday, while 'for' is used with a period of time, as in for three years.