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The Straight Lines
Quiz by Md. Shahed Mostafa Chowdhury
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Create a quiz over the following topic: Visual Art: Elements of Art, Music, Dance, and Drama A. Elements of Visual Art: There are seven primary elements of art (line, shape, form, space, color, value, texture), the components from which any artwork can be built. Any artwork that can stand the test of time will contain these elements. Element 1 â Line Line is the most fundamental concept in art. This element leads the viewerâs eye around the artwork, communicating the pieceâs meaning to the viewer. Without this element, none of the other elements could exist. At its most basic foundation, a line is simply a moving dot. When these dots overlap, the line is solid. When they do not overlap, the line is dotted or dashed. These âincompleteâ lines can represent movement or hidden material behind the primary figure. Repeated lines create patterns, and these patterned lines create a rhythm for the work. Lines can be: âĸ Curved âĸ Zigzag âĸ Horizontal âĸ Vertical âĸ Diagonal âĸ Implied âĸ Gesture âĸ Varied thicknesses âĸ Varied lengths Examples of lines and their meaning in art: Thick Lines â give emphasis and advance Thin Lines â recede and cause the eye to âlose interestâ Straight Lines â rarely found in nature, thus are inorganic. Straight lines are dynamic and mechanistic. Curved Lines â gently change directions and have no sharp angles, suggesting calmness â Curved lines are more readily found in nature and are thus considered organic lines Works with pronounced curved lines include Van Goghâs The Starry Night (1889). Note the movement across the sky.
Let's Make Shapes! A line connects two points. A line is longer than it is wide. Lines can be short, and lines can be long. Lines can be straight, and lines can be curved. You can bend lines to make a shape. You can join straight lines together to make a shape. You can join curved lines together to make a shape. There are many kinds of shapes. Circles, squares, rectangles, and triangles are geometric shapes. We can use geometric shapes to draw many things. When a line goes all the way around, it makes a circle. You can use a circle, three small circles, and a curved line to make a face. On another piece of paper, draw a circle. Then make it a mouse with eyes, ears, and whiskers. Use lines and more circles. If we cut a circle in half, we get two half-circles. You can use four half-circles to draw a caterpillar. On another piece of Then make it into a fish paper, draw a half-circle. with eyes, a tail, and fins. When a line turns a corner three times, it makes a triangle. Triangles have three sides and three corners. You can use triangles to make a face on a pumpkin. On another piece of paper, Then make it into a tree draw a triangle. with leaves and a trunk. When a line turns a corner four times, it makes a square. A square has four sides and four corners. Each side is the same length. You can use squares and half-circles to make a truck. On another piece of paper, draw a square. Then make it into a dog by adding ears, a tail, and legs. Use curved lines and straight lines. A rectangle has four sides, just like a square. Two sides are the same length. The other two sides are another length. You can use rectangles, circles, squares and lines to draw a bus. On another piece of paper, draw a rectangle. Then make it a house with a roof, two windows, and a door. Use a triangle and three rectangles. Now, on another piece of paper, make a picture using all of the shapes: circles, squares, triangles, and rectangles.
7.2.1 Critical Angle 1. The critical angle is the angle of incidence at which the refracted ray: A. Bends toward the normal B. Bends away from the normal C. Travels along the boundary D. Is totally reflected Answer: C 7.2.2 Snellâs Law & Critical Angle 2. Which formula correctly represents the critical angle c when light travels from medium 1 to medium 2? A. n1cosâĄc=n2 B. n2sinâĄc=n1 C. n1sinâĄc=n2 D. n1sinâĄc=n2sinâĄ90â Answer: D 7.2.3 Total Internal Reflection 3. Total internal reflection occurs only when: A. Light travels from air to glass B. Angle of incidence is less than the critical angle C. Light travels from a denser to a rarer medium D. Refractive index of the second medium is greater Answer: C 4. Which condition is not required for total internal reflection? A. Light must travel from a denser medium B. Angle of incidence must exceed the critical angle C. Refractive index of second medium must be lower D. Light must strike at 90° Answer: D 7.2.4 Ray Diagrams & Angle Calculations 5. A ray in water (n = 1.33) hits the surface at 40°. Critical angle = 48.8°. What happens? A. Refraction only B. Total internal reflection C. No refraction D. Light stops Answer: A 7.2.5 Snellâs Law in Glass Blocks & Prisms 6. A ray enters glass (n = 1.5) from air at 30°. Which statement is correct? A. It bends away from the normal B. It bends toward the normal C. It travels straight D. It undergoes total internal reflection Answer: B 7. In a prism, the deviation of light occurs mainly because: A. Light slows down in glass B. Light speeds up in glass C. Light reflects internally D. Light cannot pass through glass Answer: A 7.2.6 Mirages 8. A mirage appears on a hot road because: A. Light reflects off the sky B. Light refracts through layers of air with different densities C. Light undergoes dispersion D. Light travels in straight lines only Answer: B 7.2.7 Dispersion Through a Prism 9. Dispersion occurs because: A. All colors refract equally B. Different wavelengths refract differently C. The prism reflects light D. White light cannot be refracted Answer: B 7.2.8 Rainbow Formation 10. A rainbow is formed due to: A. Refraction only B. Total internal reflection only C. Dispersion only D. Refraction + TIR + dispersion Answer: D 7.2.9 Optical Fibers 11. Optical fibers work mainly due to: A. Refraction B. Diffraction C. Total internal reflection D. Dispersion Answer: C 12. Which is an advantage of optical fibers? A. High signal loss B. Immune to electromagnetic interference C. Very heavy D. Slow data transmission Answer: B
CONCEPT OF INTEGERS What are INTEGERS? Integers are whole numbers that describe opposite ideas in mathematics. Integers can either be negative (-), positive (+) or zero. The integer zero is neutral. It is neither positive nor negative, but is an integer. Integers can be represented on a number line, which can help us understand the value of the integer. POSITIVE INTEGERS Are numbers to the right of zero. Are valued greater than zero. Express ideas of up, a gain or a profit. The sign for a positive integer is (+), however the sign is not always needed. Meaning +3 is the same value as 3. NEGATIVE INTEGERS Are numbers to the left of zero. Are valued less than zero. Express ideas of down or a loss. The sign for a negative integer is (-). This sign is always needed. Opposite Numbers/Integers â are the pairs of integers that have the same absolute value or have the same distance away from zero. ABSOLUTE VALUE The distance of a number from the origin (0) regardless of direction is called absolute value. The absolute value of a number is never negative. The symbol for absolute value is two straight lines surrounding the number or expression for which you wish to indicate absolute value. Examples: I 4 I = 4, +4 is read â the absolute value of 4 is 4 â I -3 I = 3, -3 is read â the absolute value of -3 is 3â - I 3 I = -3, means â the negative of the absolute value of 3 is -3 â COMPARING AND ARRANGING INTEGERS Integers can be compared using a number line. As you move to the left along the number line, the integers decrease in value. On the other hand, integers increase in value as you move to the right along the number line. To arrange integers in ascending order is to arrange them from least to greatest. This means that when you use the number line, the smallest the integer is to the left of 0 on the number line. To arrange integers in descending order is to arrange them from greatest to least. This means that when you use the number line, the largest the integer is to the right of 0 on the number line. This is read as ânine is greater than negative 12.â This is read as ânegative thirteen is less than negative 5.â This is read as ânegative eight is greater than negative 18.â
What are INTEGERS? Integers are whole numbers that describe opposite ideas in mathematics. Integers can either be negative (-), positive (+) or zero. The integer zero is neutral. It is neither positive nor negative, but is an integer. Integers can be represented on a number line, which can help us understand the value of the integer. POSITIVE INTEGERS Are numbers to the right of zero. Are valued greater than zero. Express ideas of up, a gain or a profit. The sign for a positive integer is (+), however the sign is not always needed. Meaning +3 is the same value as 3. NEGATIVE INTEGERS Are numbers to the left of zero. Are valued less than zero. Express ideas of down or a loss. The sign for a negative integer is (-). This sign is always needed. Opposite Numbers/Integers â are the pairs of integers that have the same absolute value or have the same distance away from zero. ABSOLUTE VALUE The distance of a number from the origin (0) regardless of direction is called absolute value. The absolute value of a number is never negative. The symbol for absolute value is two straight lines surrounding the number or expression for which you wish to indicate absolute value. Examples: I 4 I = 4, +4 is read â the absolute value of 4 is 4 â I -3 I = 3, -3 is read â the absolute value of -3 is 3â - I 3 I = -3, means â the negative of the absolute value of 3 is -3 â COMPARING AND ARRANGING INTEGERS Integers can be compared using a number line. As you move to the left along the number line, the integers decrease in value. On the other hand, integers increase in value as you move to the right along the number line. To arrange integers in ascending order is to arrange them from least to greatest. This means that when you use the number line, the smallest the integer is to the left of 0 on the number line. To arrange integers in descending order is to arrange them from greatest to least. This means that when you use the number line, the largest the integer is to the right of 0 on the number line. This is read as ânine is greater than negative 12.â This is read as ânegative thirteen is less than negative 5.â This is read as ânegative eight is greater than negative 18.â R
What are INTEGERS? Integers are whole numbers that describe opposite ideas in mathematics. Integers can either be negative (-), positive (+) or zero. The integer zero is neutral. It is neither positive nor negative, but is an integer. Integers can be represented on a number line, which can help us understand the value of the integer. POSITIVE INTEGERS Are numbers to the right of zero. Are valued greater than zero. Express ideas of up, a gain or a profit. The sign for a positive integer is (+), however the sign is not always needed. Meaning +3 is the same value as 3. NEGATIVE INTEGERS Are numbers to the left of zero. Are valued less than zero. Express ideas of down or a loss. The sign for a negative integer is (-). This sign is always needed. Opposite Numbers/Integers â are the pairs of integers that have the same absolute value or have the same distance away from zero. ABSOLUTE VALUE The distance of a number from the origin (0) regardless of direction is called absolute value. The absolute value of a number is never negative. The symbol for absolute value is two straight lines surrounding the number or expression for which you wish to indicate absolute value. Examples: I 4 I = 4, +4 is read â the absolute value of 4 is 4 â I -3 I = 3, -3 is read â the absolute value of -3 is 3â - I 3 I = -3, means â the negative of the absolute value of 3 is -3 â COMPARING AND ARRANGING INTEGERS Integers can be compared using a number line. As you move to the left along the number line, the integers decrease in value. On the other hand, integers increase in value as you move to the right along the number line. To arrange integers in ascending order is to arrange them from least to greatest. This means that when you use the number line, the smallest the integer is to the left of 0 on the number line. To arrange integers in descending order is to arrange them from greatest to least. This means that when you use the number line, the largest the integer is to the right of 0 on the number line. This is read as ânine is greater than negative 12.â This is read as ânegative thirteen is less than negative 5.â This is read as ânegative eight is greater than negative 18.â
The following days are a jumble of gunfire, digging, gobbled food, soldiers running in and out of the forest in small groups, distant explosions, stray shells, bandaged heads and unexpected lulls. On the very first day, before dawn, I am ordered into one of the newly dug trenches. I huddle there, squeezing my magic buttons and singing songs to the dog. When the fighting stops, the dog disappears, but a new companion takes his place. A strange little soldier crawls along the trench toward me. âPrivate Sasha!â he cries. âIâve been looking for you all day long!â Heâs old, like a grandfather, a dedushka. He has a black patch over one eye, a tape measure around his neck and a row of pins threaded into his sleeve. Hanging from his belt is the most enormous pair of scissors I have ever seen and I wonder if he uses them as a weapon. He doesnât tell me his name, so in my head he becomes Dedushka. Dedushka squats, cups his hand to his ear, peers over the top of the trench and smiles. âItâs safe to be upright . . . for now.â He helps me to my feet, dusts me off and commands me to stand as tall and straight as I can. Then he measures me. Everything from head to toe â even my toes! He writes numbers in a little notebook, strings his tape measure back around his neck, salutes and hurries away. Itâs all very strange, and I wonder if Dedushka has been bumped on the head during the battle and is now a little bit muddled. I should have given him a hug before he left. I chase after him but stop when Iâm hit by a shovelful of flying dirt. Sleepy Bear is digging a cave! âAre you going to hibernate?â I ask. Sleepy Bear chuckles. âNo, although that would be wonderful! I could do with a lo-o-o-ong sleep.â He sighs and closes his eyes. He doesnât open them again and I realise that he has gone to sleep. Standing up! I shake his arm, and he opens his eyes and keeps talking. âNo, Iâm not hibernating. Iâm digging a little nook where I can sleep and eat. Iâll hang up my raincape as a door that can open and close so it feels just like a real home . . . except for the lice . . . and the bad smells . . . and the bombs that make the walls shake and crumble.â He points further along the trench to where other soldiers are digging. âWeâre all making little houses in the ground.â âLike rabbits and moles,â I say. Sleepy Bear chuckles. âYes! And soldiers who need to hide from German bullets and bombs.â He stops digging to roll a cigarette. âShould I be making a house?â I ask. âI want to hide from German bullets and bombs, too.â Sleepy Bear flops to the ground, lights his cigarette, closes his eyes and takes a deep puff. I wait for him to answer, but, instead, he begins to snore! I poke him in the side. He snorts and he murmurs, âI think someone has already built you a house, Sasha. Keep going along this beautiful village street and you are sure to find it.â He falls asleep once more. I kiss his dusty cheek and whisper, âThank you, Sleepy Bear.â A little way along, I see Cook in a cloud of smoke. He has lit a fire, right here in the middle of the trench, and is stirring a cauldron full of kasha. He squats as he stirs. âWhat are you doing?â I ask. âCooking supper, of course!â he cries. âBut why are you doing it here?â Cook points his spoon at the ground above the trenches. âBecause if I do it up there, my pot will be filled with holes from German bullets and all of the kasha will leak out onto the ground. Itâs bad enough that our supplies canât get through German lines and thereâs nothing to cook but buckwheat for kasha. But if we lost the kasha, too . . .â âHungry soldiers,â I say. Cook nods. âAnd grumpy!â âLike Boris!â I gasp. âEven worse,â warns Cook. I picture the kasha pot full of bullet holes. And then I realise that if the kasha pot were full of holes, then Cook would be, too. I wrap my arms around Cookâs neck and say, âI think this is a very good place for cooking our supper.â I kiss his smoky cheek and run along. At the end of the trench, I find the biggest hole of all. Itâs wide and deep and as busy as a beehive in a blossom tree. Above, a group of soldiers is rolling logs into place for a roof, while below, typewriters rattle and pencils scratch and papers flutter and voices crackle out of five different radios. Their words tangle together to tell a strange wartime fairy tale about German guns and a loving father called Stalin and a Red Army regiment that is lost in the deep, dark forest and a wicked beast called Hitler and a delivery of vegetables that was hit by a bomb and blown into a million tiny pieces too small even to make soup. In the middle of it all, wrestling with a rumpled map, his rifle still slung over his shoulder, is Major Scruff. âMajor Scruff!â I run and jump into his arms. âIs this our new home?â âYes, Sasha. I suppose it is.â âIs it safe from German bullets and bombs?â I ask. He stares at me. âWere you scared in the trenches today, Sasha?â âNo,â I reply. âI had magic buttons and a dog and some songs to sing. Were you scared in the forest, Major Scruff?â âYes,â he says. âPoor Major Scruff!â I press my hand against his cheek. The dark, rough stubble is grubby with grit and his eyelids are taking a long time to open after every blink. âYou need a shave and a nap!â I scold. He chuckles. âI am too tired to shave and too busy to nap.â I scrunch my nose while I consider his problem. âI know!â I cry. âYou nap and I will shave your whiskers. That will be two jobs tumbled into one!â And so thatâs what we do. Major Scruff slumps into a chair and snoozes while I lather his face with soapy water and shave his whiskers. The soap suds travel from his face, up into his hair and down the front of his uniform, and I have to shave his jaw and chin three times because I keep missing bits, but I finally get it all done. I am just wiping his cheeks dry when the dog appears. He licks my hand, then stretches up and licks soap suds from Major Scruffâs ear. Major Scruff wakes with a start. He feels his newly shaved face and cries, âWonderful, Sasha! I feel smooth, clean, rested and ready for action.â He ruffles my hair. âWe must do this again tomorrow. Although next time, you might wake me with a gentle shake of the shoulder instead of licking my ear.â
Organic Nomenclature. What are aliphatic compounds or aliphatic hydrocarbons? An aliphatic compound or aliphatic hydrocarbon is an organic compound containing hydrogen and carbon atoms that are usually linked together in chains that are straight. The term Aliphatic has been derived from the Greek word âAleipharâ which translates to âfatâ. It is used to describe hydrocarbons that are obtained by the chemical degradation of oils or fats. What are aliphatic compounds or aliphatic hydrocarbons? The simplest organic compounds are those composed of only two elements: carbon and hydrogen. These compounds are called hydrocarbons. Hydrocarbons are separated into two types: aliphatic hydrocarbons and aromatic hydrocarbons. Aliphatic hydrocarbons are hydrocarbons based on chains of C atoms. There are three types of aliphatic hydrocarbons: Alkanes are aliphatic hydrocarbons with only single covalent bonds. Alkenes are hydrocarbons that contain at least one CâC double bond, and alkynes are hydrocarbons that contain a CâC triple bond. Occasionally, we find an aliphatic hydrocarbon with a ring of C atoms; these hydrocarbons are called cycloalkanes (or cycloalkenes or cycloalkynes). The simplest alkanes have their C atoms bonded in a straight chain; these are called normal alkanes. They are named according to the number of C atoms in the chain. The smallest alkane is methane: molecule is three dimensional, with the H atoms in the positions of the four corners of a tetrahedron. The diagrams representing alkanes are called structural formulas because they show the structure of the molecule. As molecules get larger, structural formulas become more and more complex. One way around this is to use a condensed structural formula, which lists the formula of each C atom in the backbone of the Molecule. The condensed formulas show hydrogen atoms right next to the carbon atoms to which they are attached, as illustrated for butane: The ultimate condensed formula is a line-angle formula (or line drawing) , in which carbon atoms are implied at the corners and ends of lines, and each carbon atom is understood to be attached to enough hydrogen atoms to give each carbon atom four bonds. For example, we can represent pentane (CH3CH2CH2CH2CH3) and isopentane [(CH3)2CHCH2CH3] as follows: Unsaturated Hydocarbons: Alkenes and Alkynes Alkenes Organic compounds that contain one or more double or triple bonds between carbon atoms are described as unsaturated. Unsaturated hydrocarbons have less than the maximum number of H atoms possible. Unsaturated hydrocarbon molecules that contain one or more double bonds are called alkenes. Carbon atoms linked by a double bond are bound together by two bonds, one Ī bond and one Ī bond. Double and triple bonds give rise to a different geometry around the carbon atom that participates in them, leading to important differences in molecular shape and properties. The differing geometries are responsible for the different properties of unsaturated versus saturated fats. Naming Alkenes and Alkynes Alkenes and alkynes are named in a similar fashion. The biggest difference is that when identifying the longest carbon chain, it must contain the CâC double or triple bond. Furthermore, when numbering the main chain, the double or triple bond gets the lowest possible number. This means that there may be longer or higher-numbered substituents than may be allowed if the molecule were an alkane. For example, this molecule is 2,4-dimethyl-3-heptene (note the number and the hyphens that indicate the position of the double bond). â Unsaturated Hydocarbons: Alkenes and Alkynes Unsaturated Hydocarbons: Alkenes and Alkynes Alkynes Hydrocarbon molecules with one or more triple bonds are called alkynes; they make up another series of unsaturated hydrocarbons. Two carbon atoms joined by a triple bond are bound together by one Ī bond and two Ī bonds. The sp-hybridized carbons involved in the triple bond have bond angles of 180°, giving these types of bonds a linear, rod-like shape. The simplest member of the alkyne series is ethyne, C2H2, commonly called acetylene. The Lewis structure for ethyne, a linear molecule, is: Properties of Unsaturated Hydocarbons: Alkenes and Alkynes Ethylene (the common industrial name for ethene) is a basic raw material in the production of polyethylene and other important compounds. Over 135 million tons of ethylene were produced worldwide in 2010 for use in the polymer, petrochemical, and plastic industries. Ethylene is produced industrially in a process called cracking, in which the long hydrocarbon chains in a petroleum mixture are broken into smaller molecules. Halogens can also react with alkenes and alkynes, but the reaction is different. In these cases, the halogen reacts with the CâC double or triple bond and inserts itself onto each C atom involved in the multiple bonds. This reaction is called an addition reaction. One example is Properties of Unsaturated Hydocarbons: Alkenes and Alkynes Hydrogen can also be added across a multiple bond; this reaction is called a hydrogenation reaction. In this case, however, the reaction conditions may not be mild; high pressures of H2 gas may be necessary. A platinum or palladium catalyst is usually employed to get the reaction to proceed at a reasonable pace: CH2=CH2+H2âmetalcatalystCH3CH3 CH2=CH2+H2âmetalcatalystCH3CH3.