IAF Group C flashcards

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

Odd days in a year

An ordinary year has one odd day and a leap year has two. Odd days are the remainder when total days are divided by seven, and they fix the day of the week.

Clock hand angle formula

The angle between the hour and minute hands is the absolute value of 30H minus 5.5M degrees, where H is the hour and M the minute.

Syllogism validity rule

A conclusion follows only if it is true in every possible Venn diagram of the premises. A conclusion true in just one arrangement is not valid.

Blood relation notation

Use a vertical line for parent-child, a horizontal line for siblings, and a double line for marriage. Mark each person plus for male and minus for female.

Successive percentage change

Two successive changes of a percent and b percent give a net change of a plus b plus ab divided by 100 percent. A 20 percent rise then fall gives a 4 percent fall.

Compound interest two-year difference

For two years the difference between compound and simple interest equals the principal multiplied by the square of the rate divided by 100.

Average speed equal distances

When equal distances are covered at speeds x and y, the average speed is 2xy divided by the sum of x and y, not the simple mean.

Boat and stream speeds

Downstream speed is boat plus stream and upstream is boat minus stream. Boat speed is their average and stream speed is half their difference.

HCF and LCM product rule

For two positive integers, the product of their HCF and LCM equals the product of the numbers themselves. This lets you find one from the other.

Allegation rule

When quantities with values a and b are mixed to give a mean m, the ratio of the quantities is m minus b to a minus m.

Articles a and an

Use a before a consonant sound and an before a vowel sound. Say an hour and an honest man, but a university and a European.

Present perfect with since

Use since with a starting point in time and for with a duration. Both take the present perfect or present perfect continuous, not the simple present.

Active to passive rule

The object becomes the subject, the verb becomes a form of be plus past participle, and the doer follows by. Tense and number are preserved.

Affect versus effect

Affect is usually a verb meaning to influence. Effect is usually a noun meaning the result. Remember the pair with the phrase cause and effect.

Idiom bolt from the blue

A bolt from the blue means a sudden and unexpected shock or event. It comes from a lightning strike on a clear sky.

Fundamental Rights Part III

Fundamental Rights are in Part III, Articles 12 to 35. Article 32, the right to constitutional remedies, was called the heart and soul of the Constitution.

Constitution adoption date

The Constitution was adopted on 26 November 1949 and came into force on 26 January 1950. The 42nd Amendment in 1976 added socialist and secular to the Preamble.

Tropic of Cancer states

The Tropic of Cancer passes through eight Indian states, from Gujarat and Rajasthan in the west to Mizoram and Tripura in the east.

RBI establishment and role

The Reserve Bank of India was established in 1935 and nationalised in 1949. It issues currency, manages monetary policy, and acts as banker to the government.

Aircraft control surfaces

Ailerons control roll about the longitudinal axis, elevators control pitch about the lateral axis, and the rudder controls yaw about the vertical axis.

Oleo strut function

An oleo strut uses compressed nitrogen and hydraulic fluid to absorb landing impact and damp rebound. The fluid passes through an orifice to dissipate energy.

Pitot-static system errors

A blocked pitot tube causes the airspeed indicator to behave like an altimeter. A blocked static port affects airspeed, altitude, and vertical speed readings.

AVGAS and Jet A-1

AVGAS 100LL is the low-lead petrol for piston engines. Jet A-1 is the kerosene-based fuel for turbine engines. Mixing them is prohibited.

Torque wrench use

A torque wrench must be calibrated and set to the maintenance manual value. Apply steady force at the handle and never use it to loosen fasteners.

Byte and kilobyte

One byte equals eight bits. One kilobyte equals 1024 bytes, one megabyte equals 1024 kilobytes, and one gigabyte equals 1024 megabytes.

Excel absolute reference

A dollar sign before column and row, as in $A$1, fixes the reference when a formula is copied. Without dollar signs the reference shifts.

Email To Cc Bcc

To holds the people who must act, Cc holds those informed, and Bcc hides recipients from each other. Use Bcc for large or confidential lists.

First computer generation

First-generation computers used vacuum tubes, were large and hot, and were programmed in machine language. The ENIAC is a well-known example.

Inward mail diarising

Inward mail is entered in a diary with a serial number and date, then put up through the proper channel. This creates an auditable record of receipt.

File movement register

A movement register records the issue and return of files, with date and receiving officer, so that a file's location can always be traced.

Dice opposite faces

On a standard die, opposite faces always sum to seven. So one is opposite six, two is opposite five, and three is opposite four.

Divisibility by eleven

A number is divisible by eleven when the difference between the sums of digits in alternating positions is zero or a multiple of eleven.