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Class 12 - Unit 1
Quiz by Doan Phuong Nguyen Ha
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​1. PRONUNCIATION
steam
really
clean
weather
​His father used to be a ............... professor at the university. Many students admired him.
distinctive
distinct
distinguishing
distinguished
1. PRONUNCIATION
His father used to be a ............... professor at the university. Many students admired him.
3. CLOSEST in meaning
The speaker paused. He hesitated to answer the direct question raised by the audience.Â
4. OPPOSITE in meaning
I was relieved by the news that they had gone home safe and sound.
5. Choose the correct response.
Have you decided who to talk about?
6. OPPOSITE in meaning
She comes from an admirable and respectable family.
7. CLOSEST in meaning
The government's plans to cut taxes really stimulated the economy.
8. Michael Hart was the ............... of Project Gutenberg, one of the longest-lasting online library projects.
9. Einstein ............... a great impact on modern physics.
10. That disabled boy's victory in the race ............... a good example to all the students in the school.
11. STRESS
12. STRESS
13. PRONUNCIATION
14. He is ............... influenced by his father and grandfather. His behaviors and decisions are exactly the same.
15. The company has a well-deserved ............... for being reliable.
16. CLOSEST in meaning
Her courage not only inspired her followers but moved her rivals as well.
17. OPPOSITE in meaning
They are going to have to amputate his left leg which was badly injured in the accident.
18. Choose the correct response.
What do you think about Steve Jobs?
19. We have ................ the kittens carefully and considered them children.
20. She has a wonderful voice but unfortunately, she never gets the ................ to sing in public.
5 class 12 Unit part 15 class Unit 12 part 2EC - Unit 12 (Core Low Class)Apklausa 12 unit 4 classElectrostatics The section of CBSE Class 12 Physics electrostatic potential and capacitance notes mainly deals with the in-depth analysis of electromagnetic phenomena when they are not performing any movements. Additionally, it is divided into ten further sub-topics to study the companion processes of reaching the state. These are - 1. Electric charge In this section of Physics ch 2 Class 12 notes, you get to learn about the basic features of electric charge and its expression in Physics. Along with its basics, the sections help to understand the full potential of charge. Different aspects of Charge included in Class 12 Physics Chapter 2 notes are - Definition Type: Positive and Negative Charge Unit and dimensional formula Point Charge Properties of Charge Comparison of Charge and Mass Methods of Charging Electroscope 2. Coulomb's Law Force is created when charges of opposite signs attract each other, and they repulse if the signs are the same. Coulomb's law tries to define this phenomenon through a mathematical formula, explicitly mentioned in Physics Class 12 notes Chapter 2. Moreover, there is key information about the variation of the constant k and its effect on a medium. Coulomb's law's vector form and the principle of superimposition are also explained in ch 2 Physics Class 12 notes. (Image will be uploaded soon) 3. Electric Field As stated in Class 12 Physics Chapter 2 notes, every positively or negatively charged particle has their respective electric fields. It feels a force at the time of interaction which might be attraction or repulsion. As it arises from electric charge, it is crucial to know about its different parts like - Electric field intensity Relation between electric force and electric field Super imposition of electric field Point charge Continuous charge distributions Properties of Electric Field Lines Motion of Charged Particles in an Electric field Learning more about the electric field from electric potential and capacitance notes Class 12 helps a student to get a grasp of upcoming chapters. 4. Electric Potential Energy When energy helps a charge to move from an electric field, it is known as the Electric Potential Energy. This section of electrostatic chapter Class 12 notes requires a student to study the Electron volt (eV), and the potential energy that an n number of charges can hold. 5. Electric Potential This section of Class 12 Physics Chapter 2 notes focuses on in-depth learning of Electric Potential or Voltage. Basically, it defines the potential movement of energy. 6. Relation between Electric Field and Potential Apart from knowing more about the relationship between the two values, Physics Class 12 Chapter 2 notes also discuss equipotential surfaces. 7. Electric Dipole Essentially, 'Dipoles' are two opposite points of charge represented with q and –q, with their distance between each other being 2a. Electric Dipoles are crucial in your study of Physics Class 12 Chapter 2 notes to learn more about electric fields and their potential. Additionally, Class 12 Physics Chapter 2 notes focus on the influence of electric dipoles on a uniform electric field mainly through Force and Torque, Work, and Potential Energy. In the last part of Electrostatics, further focus is on using the formulas to their fullest potential. It includes subsections of Electric Field, Electric Potential Energy, Electric Potential, and Electric Dipole. In the notes for electrostatic potential and capacitance, you will find proper solutions accompanied by clear and crisp diagrams for better understanding. 8. Gauss's Law Apart from just discussing the Gauss's Law, in Physics Class 12 ch 2 notes there is a thorough explanation of its properties and applications. The Gauss' Law states that net electric flux passing through a hypothetical closed surface is equal to the net electric charge present within the same closed surface. Being a broad part of the whole chapter, you may need to spend a little more time on it. Moving forward, it starts discussing the properties of conductors in relation to Gauss's Law. The Class 12 Physics notes Chapter 2 perfectly defines the journey to Gauss' Law from Coulomb's Law. Here is the Gauss's Law present in the Class 12 Physics ch 2 notes, (image will be uploaded soon) 9. Capacitors There is a dedicated section about Capacitors in the Class 12 Physics Chapter 2 notes elucidating its functions and importance as storage of potential electric energy. After explaining the structure of a capacitor, it points out the different types, parallel plate, spherical and cylindrical. The section of Chapter 2 notes of Physics Class 12 is further divided into subheads like: Properties of an ideal battery Grouping of capacitors Simple circuits (Series and Parallel) Dielectric Van de Graaff generator Combination of drops Charge distribution method Wheatstone Bridge-based circuit Extended Wheatstone Bridge Infinite network of capacitors Redistribution of charge between two capacitors Vedantu prepares the Class 12 Physics Chapter 2 notes with help from subject matter experts. In the PDF, you get a comprehensive idea of the topic along with potential answers to the most asked questions. Furthermore, the detailed explanation on each section and subsections are written in a simple language allows a student to ace their exams with wholesome knowledge. These Physics Chapter 2 Class 12 notes are going to be one of the best supplementary study materials besides a student’s textbooks. Visit the Vedantu website or download the app to get your hands on all important notes! Important Questions A charge of 4 × 10–8C is uniformly distributed on the surface of a spherical conductor, having a radius of 15 cm. Determine the electric field just outside this sphere at a point that is 15 cm from the centre of this sphere. Determine the capacitance given that the distance between the two plates has been reduced by half and the parallel plate capacitor holds a capacitance of 20 pF (where 1pF = 10-12 F) having air between the two plates. What will be the total capacitance of a combination where three capacitors, each having a capacitance of 20 pF, are connected in series. A square having a side of 10 cm has a 500 µC charge at its centre. Determine the work done to move a charge of 10 µC between two points that are diagonally opposite each other on the square. At an equatorial point, what will be the electrostatic potential because of an electric dipole? Calculate the work done to move a test charge, q, through a length of 1 cm along the equatorial axis of an electric dipole? Polarisation A capacitor has its plates enclosed in a medium that can be filled by insulating substances. A net dipole moment is then induced by an electric field in the dielectric. This event causes the field in an opposite direction. Equipotential Surface An equipotential surface is a type of surface where the potential always has a constant value. If considered as a point charge, the concentric spheres that are centred at a particular area of this charge are basically equipotential surfaces. Advantages of Vedantu's Revision Notes: A Comprehensive Resource for Effective Learning There are several reasons why one may refer to Vedantu's revision notes for studying a subject like Electrostatic Potential and Capacitance. Here are some key points: Comprehensive Coverage: Vedantu's revision notes provide a comprehensive coverage of the entire topic, ensuring that all important concepts and subtopics are included. Concise and Organized: The notes are designed to be concise, focusing on the key points and core ideas. They are organized in a structured manner, making it easy for students to navigate and revise the content. Simplified Explanation: The revision notes offer simplified explanations of complex concepts, making them more accessible and easier to understand. This helps students grasp the material more effectively. Key Formulas and Equations: The notes highlight the key formulas and equations relevant to the topic, ensuring that students have a clear understanding of the mathematical aspects of Electrostatic Potential and Capacitance. Examples and Illustrations: Vedantu's revision notes often include examples and illustrations that help clarify concepts and provide practical applications, enabling students to better relate theory to real-world scenarios. Quick Recap: The revision notes serve as a quick recap of the important points, allowing students to review the material efficiently before exams or assessments. Exam-Oriented Approach: Vedantu's revision notes are designed with an exam-oriented approach, focusing on the topics and concepts that are frequently asked in examinations. This helps students prepare effectively and increase their chances of scoring well. Accessible Anytime: Vedantu's revision notes are easily accessible online, allowing students to study at their convenience and revise the material anytime, anywhere.Test unit 1+2 senior c classIons Ions are charged substances that have formed through the gain or loss of electrons. Cations form from the loss of electrons and have a positive charge while anions form through the gain of electrons and have a negative charge. Cation Formation Cations are the positive ions formed by the loss of one or more electrons. The most commonly formed cations of the representative elements are those that involve the loss of all of the valence electrons. Consider the alkali metal sodium (Na) . It has one valence electron in the n=3 energy level. Upon losing that electron, the sodiu ion now has an octet of electrons from the second energy level and a charge of 1+ . The electron arrangement of the sodium ion is now the same as that of the noble gas neon. Consider a similar process with magnesium and aluminum. In this case, the magnesium atom loses its two valence electrons in order to achieve the same arrangement as the noble gas neon and a charge of 2+ . The aluminum atom loses its three valence electrons to have the same electron arrangement as neon and a charge of 3+ . For representative elements under typical conditions, three electrons is usually the maximum number that will be los. Representative elements will not lose electrons beyond their valence because they would have to "break" the octet of the previous energy level which provides stability to the ion. Anions Anions are the negative ions formed from the gain of one or more electrons. When nonmetal atoms gain elections, they often do so until their outermost principal energy level achieves an octet. For fluorine, which has an electron arrangement of (2, 7), it only needs to gain one electron to have the same electron arrangement as neon. Forming an octet (eight electrons in the outer shell) provides stability to the atom. Fluorine will gain one electron and have a charge of 1− . The electron arrangement of the fluoride ion (2, 8) will also change to reflect the gain of an electron. Oxygen has an electron arrangement of (2, 6) and needs to gain two electrons to fill the n=2 energy level and achieve an octet of electrons in the outermost shell. The oxide ion will have a charge of 2− as a result of gaining two electrons. Under typical conditions, three electrons is the maximum that will be gained in the formation of anions. Subatomic Particles in an Ion Since ions form from the gain or loss of electrons, we can also look at the number of subatomic particles (protons, neutrons, and electrons) found in an ion. Remember that the number of protons determines the identity of the element and will not change in a chemical process. Example 2.5.1 How many protons, neutrons, and electrons in a single oxide (O2−) ion? Solution Oxygen has the atomic number 8 so both the atom and the ion will have 8 protons. The average atomic mass of oxygen is 16. Therefore, there will be 8 neutrons (atomic mass−atomic number=neutrons) . A neutral oxygen atom would have 8 electrons. However, the anion has gained two electrons so O2− has 10 electrons. We can also use information about the subatomic particles to determine the identity of an ion. Example 2.5.2 An ion with a 2+ charge has 18 electrons. Determine the identity of the ion. Solution If an ion has a 2+ charge then it must have lost electrons to form the cation. If the ion has 18 electrons and the atom lost 2 to form the ion, then the neutral atom contained 20 electrons. Since it was neutral, it must also have had 20 protons. Therefore the element is calcium. Polyatomic Ions A polyatomic ion is an ion composed of two or more atoms that have a charge as a group (poly = many). The ammonium ion (see figure below) consists of one nitrogen atom and four hydrogen atoms. Together, they comprise a single ion with a 1+ charge and a formula of NH+4 . The hydroxide ion (see figure below) contains one hydrogen atom and one oxygen atom with an overall charge of 1− . The carbonate ion (see figure below) consists of one carbon atom and three oxygen atoms and carries an overall charge of 2− . The formula of the carbonate ion is CO2−3 . The atoms of a polyatomic ion are tightly bonded together and so the entire ion behaves as a single unit. The figures below show several examples. Soult Screenshot 2-2-1.png Figure 2.5.1 : The ammonium ion (NH+4) is a nitrogen atom (blue) bonded to four hydrogen atoms (white). Soult Screenshot 2-2-2.png Figure 2.5.2 : The hydroxide ion (OH−) is an oxygen atom (red) bonded to a hydrogen atom. Soult Screenshot 2-2-3.png Figure 2.5.3 : The carbonate ion (CO2−3) is a carbon atom (black) bonded to three oxygen atoms. The table below lists a number of polyatomic ions by name and by structure. The heading for each column indicates the charge on the polyatomic ions in that group. Note that the vast majority of the ions listed are anions - there are very few polyatomic cations. 1− 2− 3− 1+ Table 2.5.1 : Common Polyatomic Ions acetate, CH3COO− carbonate, CO2−3 arsenate, AsO3−3 ammonium, NH+4 bromate, BrO−3 chromate, CrO2−4 phosphite, PO3−3 chlorate, ClO−3 dichromate, Cr2O2−7 phosphate, PO3−4 chlorite, ClO−2 hydrogen phosphate, HPO2−4 cyanide, CN− oxalate, C2O2−4 dihydrogen phosphate, H2PO−4 peroxide, O2−2 hydrogen carbonate, HCO−3 silicate, SiO2−3 hydrogen sulfate, HSO−4 sulfate, SO2−4 hydrogen sulfide, HS− sulfite, SO2−3 hydroxide, OH− hypochlorite, ClO− nitrate, NO−3 nitrite, NO−2 perchlorate, ClO−4 permanganate, MnO−4 The vast majority of polyatomic ions are anions, many of which end in -ate or -ite. Notice that in some cases such as nitrate (NO−3) and nitrite (NO−2) , there are multiple anions that consist of the same two elements. In these cases, the difference between the ions is the number of oxygen atoms present, while the overall charge is the same. As a class, these are called oxyanions. When there are two oxyanions for a particular element, the one with the greater number of oxygen atoms gets the -ate suffix, while the one with the fewer number of oxygen atoms gets the -ite suffix. The four oxyanions of chlorine are shown below, which also includes the use of the prefixes hypo- and per-. ClO− , hypochlorite ClO−2 , chlorite ClO−3 , chlorate ClO−4 , perchlorate Not your usual ion Soult Screenshot 2-2-4.png "Drink you milk. It's good for your bones." We're told this from early childhood, and with good reason. Milk contains a good supply of calcium, part of the structure of bone. However, there are two other ionic components of hydroxyapatite, the mineral component. Phosphate ion and hydroxide ion make up the remainder of the inorganic material in bone. News You Can Use Bone is a very complex structure. It is composed of protein (mainly collagen), hydroxyapatite (a calcium-phosphate-hydroxide mixture), some other minerals, and contains 10 - 20% water. The calcium/phosphate ratios are not stoichiometric, but vary somewhat from one portion of bone to the next. Bones are very strong but will break under enough stress. Regular exercise and proper nutrition help to increase bone strength. Watch a video about bone structure at http://www.youtube.com/watch?v=d9owEvYdouk Nitrate is an anion with a complex bonding structure. Major sources for this ion in drinking water are runoff from fertilizer, septic tank leakage, sewage, and natural deposits. High concentrations of nitrates represent a significant health hazard, especially to infants. The nitrate in the body is converted to nitrite, which then binds to hemoglobin. This binding decreases the ability of hemoglobin to transport oxygen, thus depriving the cells of the O2 needed for proper functioning. Cyanide production is widespread throughout nature. Forest fires will produce significant amounts of cyanide. Many plants contain cyanide, and it is produced by a number of bacteria, algae, and fungi. Cyanide is used industrially in metal finishing, iron and steel mills, and in organic synthesis processes. This material is also an important component for the refining of precious metals. Formation of a complex between cyanide and gold allows extraction of this metal from a mixture.Class 12