GeneralLET Review Program

2009

Area: Science

1. Classes in science follow the scientific procedure. What step in experiments follows the definition of the problem?a. Formulate hypothesisb. Gather relevant materials c. Draw conclusions d. State generalizations

LET 1999

2. The man could not be convinced by the findings on the fallen bridge. To be sure, he advised verification througha. objectivityb. critical analysisc. curiosityd. rationality

LET 2002

3. One who attempts a new way of doing things or applies a new solution to a problem is said to possess _____.a. Curiosityb. Responsibilityc. Open-mindednessd. Creativity

LET April 200

4. Which of the following processes is better associated with technology than with science?a. Constructing concepts and laws.b. Discovering forms of matter.c. Designing a workable system.d. Observing natural phenomena.

LET 2003

5. Which of the following is the primary reason why scientists repeat the measurement they take during experiments?a. To estimate on experimental errorb. To change the experimental conditionsc. To list the data in a tabulationd. To find out if the equipment is working

LET 2003

6. The application of scientific concepts and principles is called _____.a. ecologyb. physiologyc. technologyd. biology

LET 2003

7. During an investigation, we follow several steps. Arrange the following in the most logical manner.

1. Formulate hypothesis2. Perform an experiment3. State the problem clearly4. Draw a generalization

a. 4, 1, 2, 3 c. 3, 1, 2, 4b. 1, 2, 3, 4 d. 2, 3, 1, 4

LET 2004

8. Scientists also find that other stalky vegetable such as carrots also help lower blood pressure. This statement is BEST classified asa. experimentb. nonessential factc. findingd. prediction

LET 2004

9. Researchers gave rats a dose of 3-m butyl phypthalide and measured changes in the rats’ blood pressure. This statement is BEST classified asa. experimentb. predictionc. hypothesisd. finding

LET 2006

10. Researchers believe that the celery helps lower blood pressure by causing muscles that line blood vessels to relax. This is BEST classified as:a. experimentb. findingc. predictiond. hypothesis

LET 2006

11. Radium was discovered bya. Joseph John Thomsonb. Albert Einsteinc. Pierre and Marie Curie d. Albrecht Van Haller

LET 1998

Joseph John Thomson discovered electron.Albert Einstein was famous for his Theory of

Relativity.Albrecht Van Haller was credited with writing the

first standard Physiology textbook.

12. The first Filipino who was declared as scientist and who has contributed much in Science isa. Dr. Pacifico Marcosb. Dr. Henry Moseleyc. Dr. Eliseo Kintanard. Dr. Alfredo Santos

LET 1998

13. Who is the scientist who is likewise recognized as an International Statesman?a. Benjamin Franklinb. Thomas Jeffersonc. Alexander Hamiltond. George Washington

LET 2003

14. A British physician and bacteriologist, Sir Ronald Ross was awarded the Nobel Prize in medicine for his researches in thea. Transmission of malariab. Liquid rocketc. prevention of hepatitisd. control of cholera

LET 1998

15. Who conducted extensive experiments on pea plants, formulated the laws of heredity and is considered to be the “father of genetics?”a. C. Barrb. Gregor Mendelc. J. Lamarckd. Charles Darwin

LET 2004

16. The astronomer Copernicus was the first person to publicly state that the Earth _____.a. Revolves around the sunb. Does not movec. is center of the solar systemd. is slowing down

LET April 2008

17. Earth day is celebrated on April 22 every year. Historically this day took off in the Philippines sincea. 1960’sb. 1950’sc. 1940’sd. 1970’s

LET 2002

18. Meteorology is a very important branch of natural science, without which we cannot be informed of forthcominga. Earthquakeb. Typhoonc. meteor d. comet

LET September 2008

19. A group of students tried to find if the volume would affect the mass and density of a piece of metal. The data are shown on the table below

Based on the trials made, which among the following conclusions can be formulated?

I. Density of a material is constant.II. Mass is inversely proportional to volume.III. Volume is directly proportional to mass.IV. Density is dependent on mass and volume.

a. I and II b. I and III c. III and IV d. I and IVLET 1998

LET September 2008

Trial Volume (cm3) Mass (g) Density (g/cm3)

1 10 15 1.5

2 40 60 1.5

3 5 7.5 1.5

4 160 240 1.5

20. The volume and mass for each of five metal pieces are shown in the following table. Which of the metal pieces has the LOWEST density?

a. Calcium c. Berylliumb. Zinc d. Osmium

LET 1998

Metal Volume (cm3) Mass (g)

Beryllium 100 185

Calcium 100 155

Osmium 10 225

Titanium 10 45

Zinc 1 7

Density = mass / volumeBe = 185/100 = 1.85Ca = 155/100 = 1.55Os = 225/10 = 22.5Ti = 45/10 = 4.5Zn = 7/1 = 7

21. Sound: Decibel:: ______: _______.a. Area:square c. Length:meterb. Capacity:hectare d. Volume:cube

LET September 2008

22. Why is a dam built wider at the bottom than at the top?a. To withstand the greater pressure at the bottom.b. It holds up the dam better than at the center.c. To balance the pressure at the top.d. It anchors the dam better.

LET 2007

• Pressure is the force over an area applied to an object in a direction perpendicular to the surface.

• It is an effect which occurs when a force is applied on a surface.

• Keep in mind that the deeper the water, the greater the water pressure. So, the bottom of your dam will need to support more pressure than the top of your dam. If you built your dam in a triangular shape, then the bottom will be wider and will be able to support more pressure.

23. When Daisy swims, she notices that if she takes a deep breath, she floats. If she exhales all the air in her lungs, she sinks. Which is the BEST explanation of Daisy’s discovery? Daisy displaces an amount of water that _______.a. has less volume than her body volumeb. weighs less than her bodyc. weighs more than her bodyd. is equal to her body weight

LET 2006

• Buoyancy is the upward force on an object produced by the surrounding liquid or gas in which it is fully or partially immersed, due to the pressure difference of the fluid between the top and bottom of the object. The net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body. This force enables the object to float or at least to seem lighter. Buoyancy is important for many vehicles such as boats, ships, balloons, and airships, and plays a role in diverse natural phenomena such as sedimentation.

24. In which of the following examples is the greatest pressure exerted?a. A barefooted person standing on the beach.b. A brick resting on the ground.c. A knife cutting a piece of meat.d. A book resting on a table.

LET 2006

25. A certain object has a mass of 250 kg. When it is brought to outer space what change is observed with its mass?a. Increased in sizeb. Decreased in amountc. Increased in weightd. Remained the same

LET 2004

26. An object weighs 30N on earth. A second object weighs 30 N on the moon. Which of the two objects has the greater mass?a. The one on the moonb. They have the same massc. cannot be determinedd. the one on earth

LET April 2008

• Weight = mg• Therefore m = w/gg on earth = 9.8m/s2 or 10 m/s2

g on the moon = 1.67m/s2 On earth = weight = 30 N/10 = 3 kg.On the moon = weight = 30/1.67 = 17.96 kg

27. Which has more mass, kilogram of feathers or a kilogram of iron?a. Both have the same massb. Ironc. featherd. cannot be determined

LET April 2008

28. What does speedometer of a moving car show?a. Average accelerationb. Instantaneous speedc. Average speedd. instant acceleration

LET 2004

29. Why is velocity classified as a vector quantity? Because velocity is _____.a. Speed expressed in kilometers per hour.b. Force and motion.c. Rate of motion.d. Speed and direction.

LET 2004

30. The force required to maintain an object at a constant speed in free space is equal to _____.a. force required to stop itb. mass of the objectc. zerod. weight of the object

LET 2007

31. Which law of force and motion explains this occurrence, when a rocket is propelled upward by the powerful downward discharge of exhaust gases?a. Universal Gravitationb. Action and Reactionc. Applied Forced. Inertia

LET 2005

32. Why does a pendulum in a grandfather clock one set in motion continue to swing, thereby regulating the clock’s movement? This due to the law ofa. Universal Gravitationb. Action and Reactionc. Applied Forced. Inertia

LET 2005

33. The propulsion of jets and rockets is based on Newton’sa. Law of Accelerationb. Law of Inertiac. Law of Interactiond. Gravitation theory

LET April 2008

34. Riders in a bus are pushed forward during a sudden stop. Which law of motion provides an explanation?a. Hooke’s Lawb. Law of Universal Gravitationc. Law of Interactiond. Law of Inertia

LET 2007

35. Which law of motion explains what happens every time we walk?a. Universal Gravitationb. Interactionc. Accelerationd. Inertia

LET 2007

36. Abroad, space shuttle astronauts strap themselves to a wall or bunk when they sleep. This is because during a change of shuttle velocity an unstrapped sleeping astronaut would likely slump into the shuttle wall and be injured. These astronauts have to be strapped down becausea. They are unable to sleep while floating free in spaceb. Gravity is weak to have them remain in bed.c. Their bodies have inertiad. Their body functions have to be constantly monitored.

LET 2007

37. Why does a bullet when discharged into the air eventually fall to the ground? This is due to the Law of _____?a. Universal Gravitationb. Applied Forcec. Inertiad. Action and Reaction

LET 2005

38. In an experiment, a vacuum is created when all air is removed from a tube. A coin and bits of confetti are released in the vacuum at the same time. They fall at the same rate and reach the bottom at the same time. The experiments proves that

I. in a vacuum, the rate of acceleration is the same for all objects regardless of weight.

II. outside a vacuum, air resistance is what makes different objects fall at different rates.

III. gravity has no effect at all on objects that fall in a vacuum.

a. I and II c. I, II and IIIb. b. I and III d. II and III

LET 2005

39. Two items of similar shapes and weighs are dropped simultaneously from a ten-storey building. Which of the following statements is correct about the falling rate of the subjects?a. The weight of the object has no effect on the falling rate.b. The shape of the objects has a minor effect on the falling rate.c. The resistance of the air has no effect on the falling rate.d. The distance of the fall has an effect on the falling rate.

LET 1998

40. In order to be able to escape the earth’s gravitational pull, an object must be travelling at a speed of _________.a. 100, 000 km/hrb. 400, 000 km/hrc. 10, 000 km/hrd. 40, 000 km/hr

LET 2003

• Escape velocity – the speed an object needs to move away from a body and not be drawn back by its gravity. On earth escape velocity is equal to 11km/s.

41. A huge rock atop a hill is about to roll down. At this instance, what kind of energy does it possess?a. Mechanicalb. Potentialc. Instantaneousd. Kinetic

LET 2003

42. What does a stick of unlit dynamite demonstrate?a. Chemical energyb. Nuclear energyc. Kinetic energyd. Potential energy

LET 2005

43. A tightly coiled spring demonstrate _____.a. Steam energyb. Kinetic energyc. Potential energyd. Chemical energy

LET 2005

44. If an object has kinetic energy, then it must also have ______.a. Impulseb. Accelerationc. Momentumd. Force

LET 2007

45. Which is the first law of thermodynamics?a. Energy can be destroyed by other powerful forms.b. Energy is dynamic in nature.c. Energy is destroyed when different forms combine.d. Energy cannot be created nor destroyed.

LET 2003

46. Which of the following statements is TRUE of nuclear fission?a. The energy process is identical to that which occurs in the sun.b. Energy is obtained by getting nucleus of the atoms to break up or split.c. Scientists can combine lighter atoms to form heavier atoms.d. Matter from the lighter atoms is changed into energy.

LET 1998

47. What type of thermonuclear reaction occurs in the sun which generates a tremendous amount of heat energy?a. Fissionb. Radiationc. Convectiond. Fusion

LET 2004

48. The atomic bomb releases a tremendous amount of energy througha. Combination of light atomsb. Fissionc. thermonuclear chaind. fusion

LET April 2008

• Nuclear fusion is a nuclear reaction of low mass nuclei fusing together to form more stable and more massive nuclei with an accompanying release of energy. It is the energy source of the sun and other stars. It provides energy for the explosion of hydrogen bomb.

• Nuclear fission is a nuclear reaction of splitting a massive nucleus into a more stable, less-massive nuclei with an accompanying release of energy. It provides the energy for the explosion of atomic bombs.

• Fusion bombs are a thousand times more powerful than fission bombs, therefore hydrogen bomb is powerful than atomic bomb.

49. What nuclear process occurs in the explosion of an atomic bomb?a. disintegration c. fissionb. integration d. fusion

LET 2003

50. The tremendous energy of the sun is produced through atomic _____.a. fissionb. radiationc. disintegrationd. fusion

LET 2007

51. Trace the conversion of energy that occurs when dry cells are used in a flashlight.a. Chemical energy to heat energy.b. Chemical energy to light energy.c. Kinetic energy to potential energy.d. Light energy to heat energy.

LET 2003

52. When lighted, the energy of alcohol in a lamp isa. Completely destroyedb. Transformed from chemical to mechanical energyc. lost while heating is doned. transformed from chemical to heat energy

LET 1998

53. Which of the following forms of energy travels in waves?a. Mechanical energy c. Sound energyB. Electrical energy d. Chemical energy

LET 1998

54. Which of the following materials can transmit sound best?a. gasb. metalc. waterd. air

LET 2003

55. Which of the following decibels would likely cause noise pollution?a. 30-40b. 90-100c. 60-70d. 10-15

LET 2004

56. Which property of sound enables us to distinguish between a particular pitch produced by a piano and that by a violin?a. Intensityb. Frequencyc. Qualityd. Wavelength

LET 2004

57. In which medium would sound travel faster?a. Copperb. Waterc. Oxygend. Air

LET 2004

58. The astronauts could not communicate with one another while on the moon’s surface. Why?a. Temperature shuts down sound.b. Air waves are irregular.c. There is no weather that occurs.d. There is no atmosphere.

LET 2004

59. What happens to the speed of sound waves as it travels from a less dense medium to a denser medium?a. The speed increasesb. The speed stays the samec. total internal reflection happensd. the speed decreases

LET September 2008

• In materials in the same phase of matter, the speed of sound is slower in the denser material. Because the denser medium has greater mass in a given volume, it has more inertia. Its particles do not move as quickly as those of the less dense material. The speed of sound in dense metals such as lead and gold is much less than the speed of sound in steel or aluminum. Lead and gold are also less elastic- another reason why the speed of sound is slower in these metals.

60. In which of the following medium would sound waves travel fastest?a. Vibrating objects c. gasesb. Liquids d. solids

LET September 2008

61. Why do we hear thunder some seconds after seeing lighting?a. Light appears brighter in the sky.b. Light travels faster than sound.c. Sound travels 1, 331 m/s.d. Sound is released later actually.

LET September 2008

62. After a transverse wave passes through a substance, no particle wave ends up far from its original position. Which of the following illustrates this principle?a. Sound waves travel through air.b. Light waves travel through outer space.c. When two waves overlap, they interfere with one another.d. A cork in water bobs up and down as waves pass.

LET 2006

63. Why are rainbows formed?a. Raindrops are composed of 7 colors.b. Sunlight is absorbed by raindrops.c. Raindrops act as prisms.d. Sunlight acts as prism.

LET 2003

64. The weather bureau gave this warning during thunderstorm. Which comes first?a. lightning flashes firstb. lightning and thunder are simultaneousc. thunder sounds spread fastd. thunder follows all lightning

LET 2001

65. Which of the following light has the longest wavelength?a. Red c. Yellowb. Blue d. Green

LET September 2008

66. What happens to the speed of a light ray as it passes from water to air?a. Increasesb. Remains the samec. decreasesd. increases then decreases

LET April 2008

67. What do rays of light demonstrate when they strike a polished piece of chrome appearing to bounce off its surface?a. Refractionb. Reflectionc. Polarizationd. Interference

LET 2006

68. Light that passes through convex lensa. Dispersesb. Convergesc. divergesd. is reflected

LET April 2008

69. What kind of mirror is used in cars to give the driver a wider area and smaller image of the traffic behind him/her?a. Double concaveb. Convexc. planed. concave

LET September 2008

70. Two pots of the same size are filled with boiling water. One pot is colored white and the other is black. In which pot will water cool faster?a. In the black potb. In the white potc. Both pots will cool at the same rated. In both pots

LET 2007

71. What do you predict will happen when you bring two bar magnet closer together?a. They will repel each other.b. They will create an alternating current

c. Nothing will happend. They will attract each other

LET 2005

72. This question refers to the drawing below: Bar Magnet Cut in Half

What do the drawings suggest?a. Cutting a bar magnet in half produces two weaker bar magnets.b. To produce two bar magnets, a large bar magnet must be cut exactly in half.c. Cutting a bar magnet in half produces two shorter bar magnets.d. A bar magnet has more than one North Pole and one South Pole.

LET 2006

S N S N S N

73. Which has the higher specific heat capacity, water or sand?a. Neither sand nor waterb. Sandc. bothd. water

LET September 2008

74. Why is it not advisable to repeatedly open the door of a refrigerator?a. It will loosen hinges of the refrigerator’s door.b. It leads to wastage in electrical energy.c. Repeated opening introduces bacteria in to the refrigerator.d. The warm air outside lowers the temperature inside, thus making the refrigeration less efficient.

LET September 2008

75. Which is the simplest substance which cannot be decomposed further by ordinary chemical means?a. Moleculeb. Compoundc. Mixtured. Element

LET 2004

76. Which of these characterizes organic compounds?a. They are compounds of any elements.b. They cannot be broken down to simpler substances.c. They always require electrical means to separate.d. They are compounds containing carbon.

LET September 2008

77. In what state is most matter in the universe?a. Plasmab. Liquidc. Gasd. Solid

LET 1998

78. Of the state of matter, which has the weakest intermolecular force of attraction?a. Plasma c. solidb. Liquid d. gas

LET September 2008

79. Which term indicates the amount of space occupied by matter?a. Densityb. Weightc. Volumed. Mass

LET 2004

80. Why do we feel cool after perspiring?a. The perspiration was condensed.b. Air entered the pores of the skin.c. The perspiration has evaporated.d. The perspiration was absorbed.

LET 2003

81. Large quantities of calcium carbonate are dumped into polluted lakes to fight the effects of acid rain. It is inferred for this action that calcium carbonate is a/an_____________________.a. acidb. neutral substancec. based. powdered substance

LET 2006

82. Which of the following is heterogeneous?a. Rain water c. sea waterb. Clean air d. kerosene

LET September 2008

83. Which of these does not belong to the other three terms?Solution Colloid Suspension Elementa. Element c. Suspensionb. Colloid d. Solution

LET September 2008

84. When water evaporates, it changes into which of the following states?a. Liquidb. Matterc. Solidd. gaseous

LET 1998

85. When ice cubes form vapor without passing through the liquid state, what process takes place?a. transpirationb. sublimationc. condensationd. evaporation

LET 2003

86. The direct transformation of a solid into the gas phase without passing through the liquid phase is calleda. Sublimation c. evaporationb. Compression d. freeze drying

LET September 2008

87. Which process occurs when dry ice, CO2 (s) is changed into CO2 (g)?

a. Evaporationb. condensationc. decompositiond. sublimation

LET 1998

88. Which of the following physical changes involve adding heat to a substance?a. Boiling and condensingb. Condensing and freezingc. Evaporating and condensingd. Melting and boiling

LET 2006

89. Jane placed some mothballs inside her cabinet. After a week, they were all gone. What happened to the mothballs?a. They were dissolved by water in air.b. They melted.c. They sublimed.d. They condensed.

LET September 2008

90. Steam burns are more damaging than burns caused by boiling water because steam ____.a. is vapor of water molecules during boilingb. occupies more space that water during boilingc. has more energy per kilogram than boiling waterd. has a higher temperature than boiling water

LET 2007

• It takes quite a lot of energy for water to change phase. Steam actually contains much more energy than does boiling water, therefore it burns far worse when it comes in contact with human skin.

There is more heat in steam at 100 degrees than water at 100 degrees.

Imagine you have 1 kg of water at 99.9 degrees and you heat it just to 100 degrees, it will not turn to steam. In order to heat it to steam, to saturate it with enough heat to turn to steam, you must add another 2260 kJ of heat. So steam at the boiling point may be substantially hotter than water, though it may not have a different temperature

91. A change in the shape or size of an object can be classified asa. Chemical change c. nuclear changeb. Mechanical change d. physical change

LET 1998

92. Choose an example of a physical change in matter.a. paper torn to piecesb. acid rain formedc. milk turned sourd. milk became cheese

LET 2003

93. A change in the composition of a substance resulting in the formation of a new substance is calleda. Mechanical changeb. Chemical changec. Physical changed. Nuclear change

LET 1998

94. In which process does a chemical change take place?a. Freezing water into ice cubes.b. Boiling water into steam.c. Condensing clouds into rain.d. Manufacturing starch in leaves.

LET 2003

95. Which has a greater density, a lake full of water or a cup full of water?a. not enough informationb. the cup full of waterc. they have the same densityd. the lake full of water

LET 2007

• Density is an intensive property of matter that is defined as the ratio of an object's mass to its volume.

• At 4°C pure water has a density (weight or mass) of about 1 g/cu.cm, 1 g/ml,1 kg/litre, 1000 kg/cu.m, 1 tonne/cu.m or 62.4 lb/cu.ft

• The density of pure water is a constant at a particular temperature, and does not depend on the size of the sample. That is, it is an intensive property. The density of water varies with temperature and impurities.

• Physical properties of matter are categorized as either Intensive or Extensive:

– Intensive - Properties that do not depend on the amount of the matter present.

• Color• Odor• Luster - How shiny a substance is.• Malleability - The ability of a substance to be beaten into thin sheets.• Ductility - The ability of a substance to be drawn into thin wires.• Conductivity - The ability of a substance to allow the flow of energy

or electricity.• Hardness - How easily a substance can be scratched.• Melting/Freezing Point - The temperature at which the solid and

liquid phases of a substance are in equilibrium at atmospheric pressure.

• Boiling Point - The temperature at which the vapor pressure of a liquid is equal to the pressure on the liquid (generally atmospheric pressure).

• Density - The mass of a substance divided by its volume

– Extensive - Properties that do depend on the amount of matter present.

• Mass - A measurement of the amount of matter in a object (grams).• Weight - A measurement of the gravitational force of attraction of

the earth acting on an object.• Volume - A measurement of the amount of space a substance

occupies.• Length

96. If the water was heated and the ink was not, which of the following would likely be the effect?a. The movement of the ink molecules would be speeded up and the water would change color more quickly.b. The movement of the water molecules would be slowed, and it would take longer for the color to change.c. The movement of the water molecules would be speeded up, causing the ink molecules to be dispersed more quickly.d. Heating would have no effect on the rate of change

LET 2006

97. Blocks of asphalt roads are left with a narrow gap in-between them in order toa. Hold extra dust and small particle of sandb. Give allowance for expansion during hot daysc. Serve as passage of water during rainy daysd. Make roads with equal blocks and gaps

LET April 2008

98. Two glass tumblers that are stuck one inside the other may be loosened bya. Pouring hot water on the outside tumbler after filling the inside tumbler with cold waterb. Pouring hot water on the outside tumbler after filling the inside tumbler with equally hot waterc. Pouring cold water on the outside tumbler after filling the inside tumbler with equally cold waterd. Pouring cold water on the outside tumbler after filling the inside tumbler with hot water

LET 1998

99. In an experiment, a drop of blue ink is placed on the surface of a glass of water. In a few minutes, the drop of ink is dispersed throughout the water, turning it light blue. The result of experiment proves thata. molecules of ink and molecules of water are in constant motionb. heat causes the ink dispersec. a new compound is formed by the combination of ink and waterd. ink molecules have less density than water molecule

LET 2005

100. Which of the following statement(s) is (are) TRUE?1. Water in a cup and water in a pot at 100 degrees C have molecules of the same degree of activity.2. It takes more burning of fuel to produce a potful of boiling water than to produce a cupful.3. The unit used in measuring the quantity of heat is the calorie.4. Potful of water has greater number of active molecules than does a cupful of water.a. 3 and 4 only c. All of these statementsb. 1 and 2 only d. None of these statements

LET 1998

101. A wedding motif is pale pink. The available orchids are all white dendrobium. What property of water will allow the change from water colored red?a. Polarityb. Surface tensionc. High/low specific heatd. Capillarity

LET 1999

102. Which of the following statements best explains why copper is the metal most widely used in electrical wiring?a. It is better conductor than aluminum and cheaper than silver.b. It is the best conductor of electricity.c. It is cheaper than aluminum.d. It has high resistance to electricity.

LET 1998

103. Why is plastic commonly used as handle of kitchen utensils?a. It is lighter than metal.b. It is a good conductor of heat.c. It is a poor conductor of heat.d. It is denser than metal.

LET 2004

104. Why is a silver spoon colder to touch than a wooden spoon when both are placed at room temperature? Because silver is___________.a. a better conductor of heatb. more shinyc. a better insulator of heatd. a better radiator of heat

LET 2006

105. Glass breaks easily. Which property of matter is exhibited?a. Tenacityb. Malleabilityc. Ductilityd. Brittleness

LET 2004

106. Atoms which tend to give up electrons during the process of chemical combination possessa. Positive valenceb. Negative valencec. neutral valenced. unchanged valence

LET April 2008

107. An atom or a group of atoms which has an excessive deficiency of electrons is calleda. Ionb. protonc. moleculesd. electron

LET 1998

108. A group of covalently bonded atoms that acts like a single atom when combining with other atoms is referred to asa. Ionic bondsb. Covalent bondsc. polyatomic iond. ionic bonded atoms

LET April 2008

109. How many protons, neutrons and electrons have 238

92Uranium?

a. 146 electrons, 92 protons, 146 neutrons.b. 146 protons, 92 electrons, 92 neutrons.c. 92 protons, 92 neutrons, 146 electrons.d. 92 protons, 146 neutrons, 92 electrons.

LET 2003

110. The history of Earth has been divided by scientists into eras. Which of the following shows the arrangement of these eras into the proper sequence from the oldest to the most recent?a. Precambrian, Paleozoic, Mesozoic, Cenozoicb. Cenozoic, Mesozoic, Paleozoic, Precambrianc. Precambrian, Mesozoic, Cenozoic, Paleozoicd. Paleozoic, Cenozoic, Precambrian, Mesozoic

LET 1998

111. Which of the following statements is NOT TRUE about comets?a. Comets generally have elongated, elliptical orbits.b. Comets are mostly frozen gases and cosmic dust.c. Comets may go around the Sun in any direction.d. Comets glow by their own light.

LET 1998

112. Which of the following causes the season?a. The distance of the Earth from the Sun.b. The rotation of the Sun around the Earth.c. The rotation of the Earth around the Sun.d. The tilting of the Earth on its axis.

LET 1998

113. Why do we see the sun rise in the east?a. The earth rotates clockwiseb. The earth rotates counterclockwisec. The sun is located in the eastd. The earth revolves towards the east

LET 2004

114. As the earth revolves due to the tilting of its axis, what natural phenomena occur?a. Global warmingb. Day and nightc. weatherd. seasons

LET 2007

115. Why do we see the sun rise in the east?a. The sun is stationary in the east.b. The earth revolves clockwise.c. The earth rotates from east to west.d. The earth rotates from west to east.

LET 2007

116. What phenomenon occurs when the length of day and night varies depending on the inclination of the earth’s axis?a. Coriolis effectb. Springc. Solsticed. Equinox

LET 2004

117. The point in the earth’s orbit when the earth is farthest from the sun is called ___.a. parallaxb. aphelionc. perigeed. perihelion

LET 2007

118. If you lose your direction while traveling at night, which star should you look for and in what constellation?

I. PolarisII. RigelIII. Ursa minorIV. Ursa major

a. I and IV c. II and IIIb. II and IV d. I and III

LET 2007

119. A weather disturbance accompanied by a 50-km/hr wind is classified as a _______.a. tropical depressionb. stormc. typhoond. tornado

LET 2003

120. When the Earth, Moon and Sun are arranged in straight line, what phenomenon is likely to occur?a. Earthquakeb. Solar Eclipsec. Lunar Eclipsed. Neap Tide

LET 1998

121. Why do mountain climbers use oxygen equipment at very high altitudes?a. There is less oxygen in upper atmosphere.b. There is no air in high altitudes.c. Oxygen fails to join the atmosphere.d. Oxygen unites with nitrogen in the atmosphere.

LET 2003

122. Where do we trace El Niño phenomenon?a. Rising Ocean levelsb. Very severe earthquakesc. Annual changes in seasond. Depletion of the ozone layer

LET 2003

123. The El Niño phenomenon which grabbed control of the world’s weather machine is identified by climatologists asa. Landslide, flashfloods, warm air currentsb. Heavy downpours, tropical storms in some part of the Earthc. Lack of rains, droughts, crop failured. All of these

LET 1998

124. Which is an abiotic component of an ecosystem?a. Sulfurb. Carbonc. Temperatured. Organisms

LET 2004

125. Which part of the cell determines the physical characteristics that could be inherited by an offspring?a. mitochondriab. genec. chromosomed. centrosome

LET 2004

126. Physical traits are transmitted from parents to offspring through ______.a. genesb. chromosomesc. gametesd. alleles

LET 2007

127. You inherited tallness from your father. Physical traits are transmitted from parents to offsprings througha. Alleles c. gametesb. Genes d. chromosomes

LET September 2008

128. Choose the 6-carbon simple sugar.a. Sucroseb. Maltosec. Lactosed. Glucose

LET 2003

129. Protein is a polymer while the monomer of this substance isa. Fatty acid c. glucosea. Amino acid d. pyruvic acid

LET April 2008

130. What form is used for one who depends entirely on others for subsistence?a. subordinateb. parasitec. mediumd. host

LET 2003

131. The Red Cross humanitarian job is to gather and give needed blood to the needy. Name the universal blood type.a. Type Ob. Type Bc. Type ABd. Type Bt

LET 2000

132. Which type(s) of blood can be given to a person with blood type A?a. Only types O and Bb. Only types O and Ac. Only types A and ABd. Only type O

LET 2006

133. Which of the following blood types can be regarded as a universal donor?a. O b. A c. AB d. B

LET 2006

134. What is the cell wall of plants made of?a. plastidsb. cytoplasmc. cellulosed. lipids

LET 2003

135. In plant cells, chloroplasts are active in the chemical processes required to make food. Animal cells have no chloroplasts. Based on this, we can conclude that________________________.a. plant cells are more complex than animal cellsb. animals must obtain food from outside sourcesc. animal cells are more complex than plant cellsd. animal cells prey upon plant cells as a food source

LET 2006

136. Without the process of meiosis, we can infer that offspring from sexual reproduction woulda. have a high degree of genetic variety.b. have twice the assigned number of chromosomes.c. be identical.d. have a number of mutations

LET 2005

137. The Jones family has had four children, all girls. The fifth child born is a boy. This change is the result ofa. conception classes taken by the parents.b. the timing of the fertility cycles.c. the father’s contribution of a “Y” chromosome.d. the “law of averages” finally catching up.

LET 2005

138. When molecules of ink turn a glassful of water into blue, what process has occurred?a. Absorption c. diffusionb. Osmosis d. solution

LET April 2008

139. What is the function of DIFFUSION in the human body?a. Regulates blood flow.b. Plays an insignificant role in the body’s functioning.c. Allows an even distribution of substances throughout all cells of the body.d. Comes into play in times of extreme illness.

LET 2005

140. We always hear doctors warning us to limit salt intake. What is the effect of salt on cells?a. Salt dehydrates the cellb. Salt makes cells swellc. salt clogs the celld. salt punctures the cell

LET September 2008