1.
Which zeros are significant in the number 0.01030
Correct Answer
A. The zero between the 1 and 3, and the zero after the 3 is significant.
Explanation
In the number 0.01030, the zero between the 1 and 3 is significant because it is between two non-zero digits. The zero after the 3 is also significant because it appears after a decimal point and is followed by a non-zero digit. Therefore, both of these zeros are significant.
2.
Round the number 45 to one significant figure.
Correct Answer
C. 40
Explanation
When rounding a number to one significant figure, we look at the first digit in the number. If the digit is 1-4, we round down, and if it is 5-9, we round up. In this case, the first digit is 4, so we round down. Therefore, the number 45 rounded to one significant figure is 40.
3.
How many significant figures should the answer have if we multiply: 5.60 x 3.2
Correct Answer
A. 4
Explanation
When multiplying numbers, the number of significant figures in the answer should be equal to the smallest number of significant figures in the original numbers being multiplied. In this case, the number 5.60 has 3 significant figures and the number 3.2 has 2 significant figures. The smallest number of significant figures is 2, so the answer should also have 2 significant figures. However, the given answer is 4, which is incorrect.
4.
How many significant figures should the answer have if we divide: 100 / 0.001
Correct Answer
D. 1
Explanation
When we divide 100 by 0.001, we get 100,000. The answer is a whole number, so it has only one significant figure.
5.
How would you write the number 200 so that you had 2 significant figures?
Correct Answer
D. 2.0 x 10^2
Explanation
To write the number 200 with 2 significant figures, we need to express it in scientific notation. In scientific notation, the number is written as a decimal between 1 and 10 multiplied by a power of 10. In this case, 200 can be written as 2.0 x 10^2, where 2.0 is the decimal between 1 and 10, and 10^2 represents the power of 10. This notation ensures that there are only 2 significant figures, which are 2 and 0.
6.
Add 15.5m, 651.8cm, and 4291 mm
Correct Answer
B. 26.309
Explanation
To find the sum of the given measurements, we need to convert all the units to the same unit. First, we convert 15.5m to cm by multiplying it by 100, which gives us 1550cm. Then, we convert 651.8cm to mm by multiplying it by 10, which gives us 6518mm. Finally, we add 4291mm to get a total of 10809mm. To convert this back to cm, we divide by 10, resulting in 1080.9cm. Adding this to the original 1550cm, we get a final sum of 2630.9cm, which is equal to 26.309 when rounded to three decimal places.
7.
Formula mass of NaCl is
Correct Answer
B. 58.5 amu
Explanation
The correct answer is 58.5 amu because the formula mass of NaCl can be calculated by adding the atomic masses of sodium (Na) and chlorine (Cl). The atomic mass of Na is 23 amu and the atomic mass of Cl is 35.5 amu. Adding these two values gives a total of 58.5 amu for the formula mass of NaCl.
8.
Substance which has formula mass of 133.5 amu is
Correct Answer
D. AlCl_{3}
Explanation
AlCl3 is the correct answer because when we calculate the formula mass of AlCl3, we find that it is equal to 133.5 amu. The formula mass of Al is 26.98 amu and the formula mass of Cl is 35.45 amu. Multiplying the formula mass of Al by 1 and the formula mass of Cl by 3, we get a total of 133.5 amu. Therefore, AlCl3 is the substance with a formula mass of 133.5 amu.
9.
All are ionic compounds except
Correct Answer
C. NO_{2}
Explanation
NO2 is the only covalent compound among the given options. AgCl is an ionic compound because it consists of a metal (Ag) and a non-metal (Cl), forming a bond through the transfer of electrons. HNO3 is also an ionic compound because it contains a metal (H) and a polyatomic ion (NO3-), forming an ionic bond. (NH4)2CO3 is also an ionic compound as it contains a metal (NH4+) and a polyatomic ion (CO3^2-), forming an ionic bond. However, NO2 is a covalent compound because it consists of non-metals (N and O), forming a bond through the sharing of electrons.
10.
Calculate the volume of CO2 gas at STP by the combustion of 20grams of CH4.
Correct Answer
B. 28dm^3
Explanation
The volume of CO2 gas produced by the combustion of 20 grams of CH4 can be calculated using the ideal gas law equation PV = nRT. Since the question states that the calculation is done at STP (Standard Temperature and Pressure), we can assume that the temperature is 273 K and the pressure is 1 atm. The molar mass of CH4 is 16 g/mol, so there are 1.25 moles of CH4 (20 g / 16 g/mol). According to the balanced chemical equation for the combustion of CH4, 1 mole of CH4 produces 1 mole of CO2. Therefore, there will be 1.25 moles of CO2 gas produced. Using the ideal gas law equation, we can calculate the volume of CO2 gas at STP, which is approximately 28 dm^3.
11.
Nitric acid can be neutralized by any base to form a salt and water, as in the following equation:
Mg(OH)_{2} + 2 HNO_{3} → Mg(NO_{3})_{2} + 2 H_{2}O
How much magnesium nitrate salt will be formed by the reaction of 250. g magnesium hydroxide with 250. g nitric acid?
Correct Answer
C. 294 g
Explanation
The equation given represents a neutralization reaction between magnesium hydroxide (Mg(OH)2) and nitric acid (HNO3). According to the balanced equation, 1 mole of Mg(OH)2 reacts with 2 moles of HNO3 to form 1 mole of Mg(NO3)2 and 2 moles of H2O. To determine the amount of magnesium nitrate formed, we need to calculate the moles of Mg(OH)2 and HNO3 present in the given masses. The molar mass of Mg(OH)2 is 58.33 g/mol, so 250 g of Mg(OH)2 is equal to 4.29 moles. The molar mass of HNO3 is 63.01 g/mol, so 250 g of HNO3 is equal to 3.97 moles. Since the reaction ratio is 1:1 between Mg(OH)2 and Mg(NO3)2, the moles of Mg(NO3)2 formed will also be 4.29 moles. The molar mass of Mg(NO3)2 is 148.32 g/mol, so the mass of Mg(NO3)2 formed will be 4.29 moles multiplied by 148.32 g/mol, which is equal to 637.2 g. Therefore, the correct answer is 294 g.
12.
Unit which is not derived is
Correct Answer
B. Kilogramme
Explanation
The kilogramme is the only unit mentioned that is not derived from any other unit. It is the base unit of mass in the International System of Units (SI) and is defined as the mass of the International Prototype of the Kilogram, a platinum-iridium cylinder kept at the International Bureau of Weights and Measures in France. The newton is derived from the kilogramme, as it is the unit of force equal to the force required to accelerate a one-kilogramme mass by one meter per second squared. The watt is derived from the newton, as it is the unit of power equal to one joule per second. The pascal is derived from the newton and the square meter, as it is the unit of pressure equal to one newton per square meter.
13.
Amount of a substance in terms of numbers is measured in
Correct Answer
C. Mole
Explanation
The amount of a substance in terms of numbers is measured in moles. A mole is a unit used in chemistry to represent a specific number of particles, which is approximately 6.022 x 10^23 particles. It allows scientists to easily compare and calculate the quantities of different substances in chemical reactions. Gram and kilogram are units of mass, not specifically used for measuring the amount of a substance. Therefore, the correct answer is mole.
14.
A single system on which all scientists all over world agree for units of measurement is called
Correct Answer
C. Both above
Explanation
The correct answer is "Both above" because SI units (International System of Units) are the globally accepted standard for measurement in scientific fields. These units provide a consistent and uniform system that allows scientists from all over the world to communicate and compare their results accurately. By agreeing on the use of SI units, scientists can ensure that their measurements are standardized and universally understood, promoting collaboration and the advancement of scientific knowledge.
15.
One nanometer is equal to
Correct Answer
C. 10^{-9 }m
Explanation
One nanometer is equal to 10-9 m. This is because the prefix "nano-" denotes a factor of 10-9 in the International System of Units (SI). Therefore, when we have a value in meters and want to convert it to nanometers, we multiply by 10-9.
16.
One kilometer is equal to how many miles?
Correct Answer
A. 1.6
Explanation
One kilometer is equal to 1.6 miles. This conversion factor is commonly used when converting distances between the metric system (kilometers) and the imperial system (miles).
17.
How many Dynes are there in 1 gram weight?
Correct Answer
A. 981
Explanation
One dyne is defined as the force required to accelerate a mass of one gram by one centimeter per second squared. Therefore, the number of dynes in 1 gram weight would be equal to the weight of the object in grams multiplied by the acceleration due to gravity. The acceleration due to gravity is approximately 981 centimeters per second squared. Hence, the correct answer is 981.
18.
1 g is equal to
Correct Answer
B. 10^{-3}kg
Explanation
1 gram is equal to 10-3 kilograms. This is because the prefix "milli" represents a factor of 10-3, meaning that there are 1000 milligrams in 1 gram. Therefore, the correct answer is 10-3kg.
19.
The solid angle lies in the category of
Correct Answer
C. Supplementary units
Explanation
The solid angle is not classified as a basic unit or a derived unit in the International System of Units (SI). Instead, it falls under the category of supplementary units. Supplementary units are additional units that are used in specific fields or applications, and they are not considered fundamental to the SI system. The solid angle is a unit used to measure the amount of space an object subtends at a point, and it is commonly used in geometry and physics.
20.
The dimension of modulus of elasticity is:
Correct Answer
A. Different from that of coefficient of viscosity
Explanation
The modulus of elasticity is a measure of a material's stiffness or ability to resist deformation under stress. It is measured in units of pressure, such as pascals (Pa). On the other hand, the coefficient of viscosity is a measure of a fluid's resistance to flow. It is measured in units of force per unit area per unit velocity, such as pascal-seconds (Pa·s). Therefore, the dimension of modulus of elasticity is different from that of coefficient of viscosity.
21.
Number can be expressed in scientific notation which employ power of:
Correct Answer
B. 10
Explanation
The answer is 10 because scientific notation is a way of expressing numbers that are very large or very small. In scientific notation, a number is written as a product of a decimal number between 1 and 10, and a power of 10. The power of 10 represents the number of places the decimal point has been moved to the left or right. Therefore, the power of 10 is used to express the magnitude of the number in scientific notation.
22.
Which quantity had different dimensions:
Correct Answer
B. Pressure
Explanation
Work, Energy, and Torque all have the same dimensions, which are force multiplied by distance. Pressure, on the other hand, has different dimensions, which are force divided by area. Therefore, Pressure is the quantity that has different dimensions compared to the others listed.
23.
The dimensions MLT^{-2 }refer to the physical quantity.
Correct Answer
B. Force
Explanation
The dimensions MLT-2 refer to force. This is because M represents mass, L represents length, and T represents time. The exponent of -2 indicates that time is squared, which is a characteristic of force according to Newton's second law of motion (F = ma). Torque is not the correct answer because its dimensions are ML2T-2, with an exponent of 2 for length and -2 for time. Mass and acceleration also do not match the given dimensions.
24.
Pencillin was discovered by
Correct Answer
A. Fleming
Explanation
Fleming is the correct answer because he is the one who discovered penicillin. Alexander Fleming, a Scottish scientist, made this groundbreaking discovery in 1928 when he noticed that a mold called Penicillium notatum inhibited the growth of bacteria. This accidental finding led to the development of the first antibiotic, penicillin, which revolutionized medicine by effectively treating bacterial infections.
25.
Hydroponics is the science of growing terrestrial plants in
Correct Answer
D. Aerated solution
Explanation
Hydroponics is the science of growing terrestrial plants in an aerated solution. This method involves growing plants without soil, using a nutrient-rich water solution instead. The solution is typically oxygenated or aerated to provide the necessary oxygen for plant roots. This allows plants to absorb nutrients directly from the solution, resulting in faster growth and higher yields compared to traditional soil-based farming. By using an aerated solution, hydroponics provides an efficient and controlled environment for plant growth, making it a popular choice for indoor farming and areas with limited access to fertile soil.
26.
Industrialization and over population has increased
Correct Answer
A. Pollution
Explanation
Industrialization and overpopulation have led to an increase in pollution. The rapid growth of industries and the rise in population have resulted in the release of harmful pollutants into the environment, such as air and water pollution. This pollution has detrimental effects on both human health and the ecosystem. It can cause various diseases and health issues, impacting the well-being of individuals. Additionally, pollution can also harm productivity by damaging crops, contaminating water sources, and reducing the overall quality of the environment. Hence, pollution is a significant consequence of industrialization and overpopulation.
27.
In biology a _________________ is the collection of inter-breeding organisms of same species.
Correct Answer
C. Population
Explanation
A population in biology refers to a group of inter-breeding organisms of the same species. It is a specific subset of a larger community and biosphere, focusing on a particular species and their interactions within a given area.
28.
All acellular, Eukaryotic organisms which are no longer classified as animals, plants or fungi are placed in Kingdom
Correct Answer
B. Protista
Explanation
Protista is the correct answer because it is the kingdom that includes all acellular, Eukaryotic organisms that are no longer classified as animals, plants, or fungi. This kingdom is characterized by organisms that are unicellular or multicellular but lack specialized tissues and organs. Protists can be found in various environments, such as freshwater, marine, and soil, and they exhibit a wide range of characteristics and lifestyles. Some examples of protists include amoebas, algae, and slime molds.
29.
What is true for Natural Cloning?
Correct Answer
D. All, A, B and C
Explanation
Natural cloning refers to the process of asexual reproduction in plants and animals, where offspring are produced from a single parent without the involvement of gametes or fertilization. This can occur through various mechanisms such as budding, fragmentation, or parthenogenesis. Additionally, regeneration and wound healing are also forms of natural cloning, as they involve the growth and development of new tissues or organs from existing ones. Lastly, the growth of tumor cells or cancers can also be considered a form of natural cloning, as these cells divide and multiply uncontrollably, giving rise to a population of genetically identical cells. Therefore, all options A, B, and C are true for natural cloning.
30.
If bacteriophages specifically target and destroy cells of Escherichia coli in petri dishes, then they will do the same in laboratory mice that have been infected by that strain. This statement is referred to as
Correct Answer
B. Hypothesis
Explanation
The given statement is a hypothesis because it proposes a possible explanation or prediction based on the observation that bacteriophages destroy Escherichia coli cells in petri dishes. The statement suggests that if this is true in petri dishes, then it will also be true in laboratory mice infected with the same strain. A hypothesis is a testable explanation or prediction that can be further investigated or tested through experiments or observations.
31.
Living together of two organisms belonging to different species is termed as
Correct Answer
C. Symbiosis
Explanation
Symbiosis refers to the living together of two organisms belonging to different species. It is a close and long-term relationship where both organisms benefit from each other. This could include mutualism, where both organisms benefit, or parasitism, where one organism benefits at the expense of the other. Commensalism, on the other hand, is a type of symbiosis where one organism benefits while the other is neither harmed nor helped. Therefore, the correct answer is Symbiosis.
32.
Dolly sheep was cloned in
Correct Answer
C. 1996
Explanation
Dolly the sheep was cloned in 1996.
33.
The practice of growing several different crops on the same land in successive years or seasons to avoid pests and diseases is termed as
Correct Answer
B. Crop rotation
Explanation
Crop rotation is the practice of growing different crops on the same land in successive years or seasons to avoid pests and diseases. This helps to break the life cycle of pests and pathogens that may be specific to certain crops, as well as replenish soil nutrients and reduce soil erosion. By rotating crops, farmers can maintain the health and productivity of their fields while reducing the need for chemical pesticides and fertilizers.
34.
The period of geologic time beginning after the end of the Mesozoic Era 70million years ago and encompassing the present. Commonly referred to as the age of mammals
Correct Answer
C. Cenozoic era
Explanation
The Cenozoic era is the correct answer because it is the period of geologic time that began after the Mesozoic Era, around 70 million years ago, and continues to the present. It is commonly referred to as the age of mammals because it is during this era that mammals diversified and became the dominant group of animals on Earth. The other options, Proterozoic era, Paleozoic era, and Mesozoic era, are incorrect as they do not fit the given time frame or description.
35.
It can be defined as the use of natural enemies to reduce the damage caused by a pest population.
Correct Answer
B. Biological control
Explanation
Biological control refers to the practice of utilizing natural enemies, such as predators, parasites, or pathogens, to minimize the harm caused by a pest population. This method involves introducing these natural enemies into the affected area to control the pest population without the use of chemicals or pesticides. By harnessing the power of nature, biological control offers a sustainable and environmentally friendly approach to pest management.
36.
Antigens in the form of modified or inactivated or killed pathogens that raise immunity against actual pathogens
Correct Answer
C. Vaccines
Explanation
Vaccines are substances that contain modified or inactivated pathogens, which are then introduced into the body to stimulate an immune response. This immune response helps the body recognize and fight off actual pathogens when encountered in the future. Antibiotics, on the other hand, are medications used to treat bacterial infections, not to raise immunity. Antibodies are proteins produced by the immune system in response to an infection or vaccination. Therefore, the correct answer is vaccines.
37.
Synonym of ALERT is _____________?
Correct Answer
C. Watchful
Explanation
The synonym of "alert" is "watchful" because both words convey the idea of being attentive and vigilant. When someone is alert, they are fully aware of their surroundings and ready to respond to any potential danger or opportunity. Similarly, being watchful means being attentive and cautious, keeping a close eye on things and being prepared to react if necessary. Therefore, "watchful" is a suitable synonym for "alert".
38.
Synonym of EMBEZZLE is _____________?
Correct Answer
D. Misappropriate
Explanation
The word "embezzle" means to dishonestly take or use money that is entrusted to you, typically from an organization or employer. The word "misappropriate" is a synonym for "embezzle" because it also refers to the act of dishonestly taking or using funds that are entrusted to someone. Therefore, "misappropriate" is the correct answer as it has the closest meaning to "embezzle".
39.
He writes ___ ink.
Correct Answer
B. In
Explanation
The correct answer is "In" because when we write, we use ink as a medium to put words on paper. Therefore, the preposition "in" is used to indicate the medium or substance in which an action is performed.
40.
Antonym of “Paucity” is____________?
Correct Answer
B. Surplus
Explanation
The antonym of "paucity" is "surplus." Paucity refers to a scarcity or lack of something, while surplus means an excess or abundance of something. Therefore, these words are opposite in meaning.