NTRCA School Level flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- স্বরবর্ণ ও ব্যঞ্জনবর্ণ
- Bangla has 11 vowel letters (স্বরবর্ণ) and 39 consonant letters (ব্যঞ্জনবর্ণ); vowel sounds attach to consonants through কার marks such as আ-কার and ই-কার.
- সন্ধি কাকে বলে
- Sandhi is the phonetic joining of two adjacent words or sounds. Examples include বিদ্যা + আলয় = বিদ্যালয় (vowel sandhi) and নিঃ + চয় = নিশ্চয় (visarga sandhi).
- কর্মধারয় সমাস
- In a কর্মধারয় compound the two words stand in apposition, one qualifying the other, as in নীলপদ্ম (নীল যে পদ্ম). The compound denotes the same object as the head word.
- Present perfect tense rule
- The present perfect is formed with have or has plus the past participle. It describes a past action linked to the present and cannot normally take a definite past time marker like yesterday.
- Triangle and circle area
- The area of a triangle equals half the base times the height. The area of a circle equals π multiplied by the radius squared, and its circumference equals 2πr.
- Simple interest formula
- Simple interest I equals principal P multiplied by annual rate r (as a decimal) multiplied by time t in years, divided appropriately: I = P × r × t ÷ 100 when r is a percentage.
- Photosynthesis equation
- Photosynthesis in chloroplasts combines carbon dioxide and water using light energy to produce glucose and oxygen. Respiration in mitochondria reverses this, releasing energy from glucose.
- National symbols of Bangladesh
- Bangladesh's national flower is the water lily (শাপলা), national fruit the jackfruit, national animal the Royal Bengal tiger, and national bird the doel (dোয়েল).
- উপমা ও রূপক
- উপমা is a simile, comparing two things explicitly with words like মতো or সদৃশ. রূপক is a metaphor, identifying one thing directly with another without a comparison word.
- অনুপ্রাস অলংকার
- অনুপ্রাস (alliteration) is a figure in which the same consonant sound is repeated in close succession within a line, producing rhythm, as in repeated ব or ত sounds.
- Reported speech tense shift
- In indirect narration a present-tense reporting verb shifts the reported clause to past tense, and pronouns and time words change: now becomes then, today becomes that day.
- Second conditional structure
- The second conditional uses if plus the simple past in the condition and would plus the base verb in the result, expressing an unreal or unlikely present situation.
- Algebraic square identities
- The key identities are (a + b)² = a² + 2ab + b² and (a − b)² = a² − 2ab + b², together with the difference of squares a² − b² = (a + b)(a − b).
- Polygon interior angle sum
- For a polygon with n sides, the sum of interior angles equals (n − 2) × 180 degrees. A regular polygon divides this sum equally among all its interior angles.
- Newton's second law
- Newton's second law states that force equals mass times acceleration (F = ma). Work equals force times displacement, and power equals work divided by time.
- Atomic number and mass number
- Atomic number counts protons and fixes the element's identity. Mass number counts protons plus neutrons. Isotopes share the same atomic number but differ in neutron count.
- Blood group compatibility
- Group O negative red cells are the universal donor because they lack A, B and Rh antigens. Group AB positive is the universal recipient, accepting blood of any group.
- Mitosis outcome
- Mitosis is cell division producing two daughter cells genetically identical to the parent, each diploid. It underlies growth and repair and differs from meiosis, which halves chromosome number.
- Derivative of power function
- The power rule states that the derivative of x to the power n is n times x to the power n minus one, valid for all real n where the function is defined.
- Integral of power function
- The indefinite integral of x to the power n is x to the power n plus one divided by n plus one, plus a constant, provided n is not equal to minus one.
- Trigonometric limit identity
- As x approaches zero, sine x divided by x approaches the limit one. This standard limit underlies the derivatives of sine and cosine functions in calculus.
- Continuity at a point
- A function is continuous at a point when its left-hand limit, right-hand limit, and actual value at that point all exist and are equal to one another.
- Equations of motion
- For uniform acceleration the equations are v = u + at, s = ut + ½at², and v² = u² + 2as, relating initial velocity u, final velocity v, acceleration a, and displacement s.
- Kinetic and potential energy
- Kinetic energy of a moving body equals ½mv². Gravitational potential energy near Earth equals mgh. Momentum, the product of mass and velocity, is conserved in collisions.
- Le Chatelier's principle
- A system at equilibrium shifts to oppose changes in concentration, pressure, or temperature. Raising pressure favours the side with fewer gas molecules; a catalyst alters only the rate.
- Alkane alkene alkyne formulas
- Alkanes follow CₙH₂ₙ₊₂ and are saturated. Alkenes follow CₙH₂ₙ with one carbon-carbon double bond. Alkynes follow CₙH₂ₙ₋₂ with one triple bond.
- Central dogma of molecular biology
- DNA replicates semi-conservatively, is transcribed into messenger RNA, and is translated at ribosomes, where each three-base codon specifies one amino acid in the protein chain.
- De Morgan's laws
- De Morgan's laws state that the complement of a union equals the intersection of complements, and the complement of an intersection equals the union of complements.
- Law of demand
- Other things being equal, quantity demanded of a good falls as its price rises, giving a downward-sloping demand curve. Exceptions include Giffen goods and status goods.
- Price elasticity of demand
- Price elasticity of demand equals the percentage change in quantity demanded divided by the percentage change in price. Values above one indicate elastic demand; below one, inelastic demand.
- Measures of central tendency
- The mean is the sum of values divided by their count. The median is the middle value of ordered data. The mode is the most frequently occurring value.
- Standard deviation meaning
- Standard deviation measures the average spread of data values around the mean. A small value indicates tightly clustered data; a large value indicates widely dispersed data.