SCERT Maharashtra Question Bank Pdf Solution Q.4.RD Answer the Following Questions. There in Pdf total 94 Answer the Following Questions. We have given full Solve in this page.
Maharashtra Question Bank Class 10 Answer the Following Solution
1) Read the given passage carefully and answer the questions.
We know that the gravitational force of the earth is applied to all objects. This force was used even when you were holding a stone in your hand. But the force you were pushing in the opposite direction with your hand was balancing it so that the stone was stable. When you let go of the hand , only gravitational force is applied to the stone, so the stone falls under its influence. When an object is moving only under the influence of gravitational motion, that motion is called free fall, that is the stone falls. In free fall, the initial velocity is zero and it is increased due to gravitational acceleration over time. At the time of free fall on the earth , the friction of the air opposes the motion of the object. So in the true sense free fall cannot happen in the air. It can happen only in vacuum.
- A) Complete the following statement by choosing the right option.
The stone held in the hand is stable because on it ….
- a) two unbalanced forces are exerted.
- b) only the gravitational force of the earth is exerted.
- c) gravitational force of the earth is not exerted.
- d) two balanced forces are exerted.
Answer: d) Two balanced forces are exerted.
B)Why does free fall not happen on the earth?
Answer: In addition to gravitational force object also experiences friction force on the earth and hence free fall not happen on the earth.
C)Why does the velocity of the object increase during the free fall?
Answer: Due to the acceleration due to gravity over time the velocity of the object increases during the free fall.
D)Which type of force exerts on the object during free fall?
Answer: Gravitational force exerts on the object during free fall.
- E) Why does free fall happen only in vacuum?
Answer: Free fall happens only in vacuum because no for other than gravitational acts upon the object in the vacuum..
2) Note the relationship between the entries in all the three columns in the table and rewrite the table.
Column-1 (Location)
Column-2 Height from the earth’s surface (km)
Column-3 g (m/s 2 ) Earth’s surface(average) 8.8 0.225 Mount Everest 36.6 9.81 The highest height ever reached by man made balloon 400 9.8 Orbit of spacecraft 35700 9.77 Orbit of communication satellite 0 8.7
Answer:
Location | Height from the earth’s surface (km) | g (m/s) |
Earth’s surface | 0 | 9.81 |
Mount Everest | 8.8 | 9.8 |
The highest height ever reached by man made balloon | 36.69 | 9.77 |
Orbit of spacecraft | 400 | 8.7 |
Orbit of communication satellite | 35700 | 0.225 |
3) Observe the given cḥart and answer the questions given below.
Element | A | B | C | D |
Electronic
configuration |
2,1 | 2,8 | 2,8,1 | 2,8,8 |
- A) Which elements are in the same row ? 1 mark
Answer: Element A and B are in the same row similarly element C and D are in same row.
- B) Which elements have the same column? 1 mark
Answer: Element A and C have same column and Element B and D also have same column.
C)Which elements are in the 18th column? 1 mark
Answer: Elements in 18th column are B and D.
D)Which element is more reactive in A and C ? 1 mark
Answer: Element C is more reactive than A.
- E) Which of the following elements A and B is found in its compound? 1 mark
Answer: Element A forms more compounds.
4) XY Compound formed by X (Atomic number 11) and Y (Atomic number 17) then answer the questions given below.
A)Determine the position of the element X and Y in the modern periodic table. 1 mark
Answer: The position of X element is in Group 1 and period 3.
The position of Y element is in Group 17 and period 3.
B) Which type of elements X and Y are metals, nonmetals or metalloids? 1 mark
Answer: Element X is a metal and Element Y is a non-metal.
C)From which block the elements X and Y are? 1 mark
Answer: Element X are from s-block and Element Y are from p-block.
D) Determine the electronic configuration and valency of these elements. 2 marks
Answer: Electronic configuration of Element X is 2,8,1 and its valency is 1.
Electronic configuration of Element Y is 2,8,7 and its valency is 1.
5) Observe the periodic table given below and write the answers of the questions.
A)Write the name and valencies of the elements in 3rd row . 2 marks
Answer: The name and the valencies of the elements in 3rd rows are given below
Name of the elements in 3rd row |
Valency |
Sodium | 1 |
Magnesium | 2 |
Aluminium | 3 |
Silicon | 4 |
Phosphorus | 3 |
Sulphur | 2 |
Chlorine | 1 |
Argon | 0 |
B)Classify the elements in this row in metal, nonmetal and metalloids.1 mark
Answer:
Metals |
Non-metals | Metalloid |
Inert gases |
Sodium | Phosphorus | Silicon | Argon |
Magnesium | Sulphur | ||
Aluminium | Chlorine | ||
C)Which block does nonmetals belong to?
Answer: Non-metals belongs to p-block.
D)Write name of any two metalloid elements.
Answer: Silicon and Germanium are the two metalloid.
6) Make a chart which shows the name of the element, valency, atomic number, electronic configuration in the 2nd row of the modern periodic table and arrange these elements in ascending order of atomic mass.
Answer:
Elements of the second row are Lithium (Li), Beryllium (Be), Boron (B), Carbon (C), Nitrogen (N), Oxygen (O), Fluorine (F).
Ascending Order
7) What physical and chemical properties of elements did mendeleev consider in compiling the periodic table ?What challenges did mendeleev face in following periodic law?
Answer: Physical and Chemical properties of elements in mendeleev’s periodic table were:
- Molecular formula of oxides and hydrides of the elements.
- Melting points, Boiling points and densities of oxides and hydrides of elements.
Challenges Mendeleev faced:
8) Explain structure of modern periodic table in short.
a.) Modern periodic table consists of seven horizontally placed rows known as periods and eighteen vertically placed columns known as groups.
b.) Each element has its corresponding box in the modern periodic table.
c.) The upper part of each box indicates Atomic Number.
d.) Besides, seven periods and two periods are placed at the bottom of the modern periodic table. They are named as, lanthanide series and actinide series.
e.) Including lanthanide series and actinide series, a total of 118 elements are present in the modern periodic table.
f.) Complete periodic table is divided into 4 blocks, namely s-block, p-block, d-block and f-block.
g.) Group 1 and 2 belong to s-block, 13 to 18 belong to p-block, Group 3 to 12 are transition elements belonging to d-block, lanthanide series and actinide series belong to f-block elements.
h.) When a zigzag line is drawn on p-block elements. elements on left hand side are metals, elements on right hand side of zig-zag line are non-metals. elements on border of zigzag line are metalloids.
9) The electronic configuration of an element is 2,8,2 then write the answers of the questions given below.
9) The electronic configuration of an element is 2,8,2 then write the answers of the questions given below.
A.) What is the atomic number of this element?
Answer: The atomic number of the given element is 12.
B.) Which column does this element belong to?
Answer: The element has atomic number 12 and hence it belongs to column number 3.
C.) Which row does this element belong to?
Answer: The element has atomic number 12 and it belongs to group 2.
D.) The chemical properties of this element will be similar to which of the following elements? (Atomic numbers are given in the bracket) N (7), Be (4) , Ar (18), Cl (17)
Answer: Chemical properties of given element will be similar to Be.
10) Balance the given chemical reaction as per the instructions below.
NaOH + H2SO4 → Na2SO4 + H2O
A) Write names of reactants and products of chemical reaction.
Answer: Reactants are Sodium Hydroxide and Sulphuric Acid, Products are Sodium sulphate and water.
B) Make a list of the elements in the chemical equation.
Answer: number of elements in reaction are 4 elements namely, Na, O, H and S.
C) Write the number of atoms of reactants and products.
Answer:
sr.no | Elements | Number of atoms in reactants. |
Number of atoms in product. |
1. | Na | 1 | 2 |
2. | O | 5 | 5 |
3. | H | 3 | 2 |
4. | S | 1 | 1 |
D) Balance the equation with proper coefficient and rewrite the equation.
Answer: Balanced chemical equation becomes :
2NaOH + H2 SO4 → Na2SO4 + 2H2O .
E) Oxidation means losing electrons then what is reduction?
Answer: Oxidation means losing electrons and reduction is gain of electrons.
11) Observe the following figure and write the answer of the question.
A) Which process is shown in the figure?
Answer: Figure shown is of Rusting of iron or corrosion of iron.
B) Explain the chemical reaction shown in the figure.
Answer: 2 Fe3+ (aq) + 4H2O (l) → Fe2O3.H2O + 6H+ (aq).
C) Write the reactions on anode and cathode.
Answer: At Anode, Fe oxidised to Fe2+.
Fe(s) → Fe+2 (aq) + 2e-.
At cathode, O2 is reduced water.
O2 + 4H+ (aq) + 4e- →2 H2O (l)
12) Draw a diagram of an electric motor and explain the structure and function of it.
Answer: Electric motor is made up of copper wired rectangular loop having resistive coating. The loop is placed in between the north pole and south pole of the magnet. The loop is placed in such a manner that the branches AB and CD are perpendicular to the direction of magnetic field. The ends of the loop are connected to the split ring. These two part of the split ring has conducting surfaces in connection with the two stable carbon brushes (E and F) respectively. Electric motor is an device which converts electrical energy into mechanical energy.
14) Explain the magnetic field created by a current around a conductor from the figure.
Answer:
Circuit is connected as shown in the figure. Copper wire is connected to cardboard as shown in the circuit. Magnetic needle is used to check the presence of magnetic fields in copper wire. When current is passed through this wire magnetic needle deflects in different directions on cardboard. These different directions indicate magnetic fields. Concentric rings are formed on cardboard. Deflection in the needle decreases as the needle moves away from the wire. The direction of the magnetic field depends on the direction of current. Direction of the magnetic field formed is according to the right hand thumb rule. In, right hand thumb rule if right hand thumb indicates direction of current then curled fingers indicate direction of magnetic field.
15) Observe the figure and write the answers to the questions asked.
A) The structure shown in the figure is of which device?
Answer: Given figure is of principle and working process of electric motor.
B) Explain the principle on which this device works .
Answer: electric motor works on the principle of electromagnetic induction. Electric current is produced in a conductor with the help of a moving magnet.
C)Write any three uses of this device.
Answer: fans, mixer, pumps work on electric motor.
16) Observe the figure and write the answers to the questions asked.
- A) The structure shown in the figure is of which device?
Answer: Given figure is of principle and working process of electric motor.
- B) Explain the principle on which this device works .
Answer: electric motor works on the principle of electromagnetic induction. Electric current is produced in a conductor with the help of a moving magnet.
C)Write any three uses of this device.
Answer: fans, refrigerators, computers work on electric motor.
17) Read the passage and answer the questions based on it. If heat is exchanged between a hot and cold object , the temperature of the cold object goes on increasing due to gain of energy and the temperature of the hot object goes on decreasing due to loss of energy.The change in temperature continues till the temperatures of both the objects attain the same value.In this process, the cold object gains heat energy and the hot object loses heat energy. If the system of both the objects is isolated from the environment by keeping it inside a heat resistant box then no energy can flow from inside the box or come into the box. In this situation we get the following principle . Heat energy lost by the hot object = Heat energy gained by the cold object. This is called the ‘Principle of heat exchange’.
A) Where does heat transfer take place?
Answer: Heat is transferred from an object with high temperature to an object with low temperature.
B) In such a situation which principle of heat do you perceive?
Answer: From the above mentioned paragraph we can learn the principle of heat transfer or heat exchange process.
C) How can this principle explain in short?
Answer: According to the principle of heat exchange, in an isolated system the amount of heat lost by hot objects is equal to the amount of heat gained by cold objects.
D) measuring the property of which substance this principle is used ?
Answer: Based on principle of heat exchange specific heat of and object is measured.
18) Explain the following temperature-time graph.
Answer:
Given temperature- time graph is the behaviour of water on heating continuous and uniformly. AB Segment from the graph indicates that for 4 minutes ice remains constant at 0 °C. This behaviour explains that the latent heat of fusion applied is used to change the state from solid to liquid where ice is converted into water. Segment BC shows continuous rise in temperature from 0℃ to 100℃. At point c water reaches its boiling point. Heat energy provided here is latent heat of vaporization it is used to change its state from liquid to gaseous state where water is converted into steam. The CD segment remains unchanged thus it indicates formation of steam from water at 100℃.
19) Explain with a ray diagram the position, size,and the nature of the various images formed by convex lenses.
A) An object is at infinity.
DIAGRAM :
Position of Object: at infinity
Position of Image: at focus F2
Image size: point image
Nature of image: real and inverted.
B) An object beyond 2F1.
Position of Object: beyond 2F1
Position of Image: Between F2 and 2F2
Image size: Smaller
Nature of image: Real and Inverted.
C) An object at 2F1.
Position of Object: At 2F1
Position of Image: At 2F2
Image size: Same size
Nature of image: Real and Inverted.
D) An object is in between F1 and 2 F2
DIAGRAM :
Position of Object: Between F1 and 2F1
Position of Image: Beyond 2F2
Image size: Larger
Nature of image: Real and Inverted.
E) An object is at focus F1
DIAGRAM :
Position of Object: At focus F1
Position of Image: At infinity
Image size: Very large
Nature of image: Real and Inverted.
F) An object is in between F1 and O
Position of Object: Between F1 and O
Position of Image: On the same side of the lens as the object
Image size: Very large
Nature of image: Virtual and erect
20) Explain in brief types of extraction of highly reactive, moderately reactive and less reactive metals according to their reactivity.
Answer: Based on reactivity metals can be highly reactive metals, moderately reactive and less reactive metals.
1.) Extraction of highly reactive metals:
Heavy metals like sodium (Na), Magnesium (Mg), and Calcium (Ca) are extracted by the process of electrolytic reduction. Heavy metals are deposited on cathode and chlorine gas is liberated at anode.
2.) Extraction of moderately reactive metals:
Moderately reactive metals like Iron, Zinc, Lead are mixed with sulphide and carbonate salts. Metals combined with sulphide salts are heated strongly in presence of excessive air and are converted into oxide. This process is called roasting. Metals combined with carbonate salts are heated in presence of less air and are converted into oxides. This process is called calcination. Further these oxides are reduced using carbon to obtain metals. These metals are further purified using electrolysis.
3.) Extraction of less reactive metals:
Less reactive metals like copper and mercury are extracted by heating solely.
21) Explain Bayer’s process of concentration of bauxite with chemical equations.
Answer: In Bayer’s process aluminum ore is heated in the presence of caustic soda product obtained is a water soluble sodium aluminate.
Aluminium ore is called Bauxite. Bauxite has several impurities like Silica SiO2, Ferric Oxide Fe2O3, Titanium Oxide TiO2. These impurities present in bauxite are removed using Bayer’s process.
Bayer’s Process: Solution of sodium aluminate is aluminate in mixed with water and is diluted it is further heated upto 140-150℃ under high pressure for several hours it reacts with aqueous sodium hydroxide.Final product concentrated alumina is obtained by calcination.
Chemical equation for bayer’s process is as mentioned below:
Al2O3.2H2O(s) + 2NaOH (aq) → 2NaAlO2 (aq) + 3H2O (l).
22) Explain in brief electrolytic reduction of alumina with a neat labelled diagram.
Answer: Aluminium ore is called Bauxite. Bauxite has several impurities like Silica SiO2, Ferric Oxide Fe2O3, Titanium Oxide TiO2. These impurities present in bauxite are removed using Bayer’s process or Hall’s process. Alumina has a very high melting point, more than 2000℃. Thus reduction of alumina is carried out in the mixture of cryolite and fluorspar which decreases the melting point by almost 1000℃. Reaction is carried out in a steel tank which acts as an electrolyte cell. Graphite is used as anode whereas, Graphite lining is used as cathode. When electric current is passed through this cell electrolysis of alumina occur.
At Anode: Oxidation of O2 takes place and four electrons are released.
2O2-→ O2 + 4e-.
At Cathode: Reduction of Aluminium ions takes place.
Al+3 + 3e- → Al (l).
Molten alumina is heavier than electrolyte and thus, settles down where it is removed gradually through the outlet.
23) Observe the figure and answer the following.
A) Write the name of the method.
Answer: Given figure shows electrolyte reduction of alumina.
B) What is used as anode and cathode in this method?
Answer: Anode is made up of graphite and cathode is made up of graphite lining.
C) Write molecular formula and use of cryolite.
Answer: Molecular formula of cryolite is Na3AlF6. Function of cryolite is to decrease the melting point of alumina by 1000℃.
D) Write anode reaction.
Answer: At Anode: Oxidation of O2 takes place and four electrons are released. 2O2-→ O2 + 4e-.
E) Write cathode reaction.
Answer: At Cathode: Reduction of Aluminium ions takes place.
Al+3 + 3e- → Al (l).
24) Observe the figure and name and explain in brief the following methods
A) Froth Flotation Method.
Answer:- The Froth Flotation Method works on the principle of hydrophilic and hydrophobic properties. Metal sulphide particles are hydrophobic and gauge particles are hydrophilic in nature. Metal ore is finely chopped and added to the tank containing water. Vegetable oil is also added to form froth. Compressed air is passed through the froth. Blown air creates air bubbles. Rotator at the center of the tank rotates the mixture. Rotation of mixture causes foam formation. Foam carries metal sulphides with them. foam floats on water hence this type of method is known as froth flotation method.
B) Magnetic separation.
The Magnetic Separation method works on the principle of magnetic properties of ore. Magnetic separation method requires an electromagnetic machine. Machine is made up of iron rollers and a conveyor belt made up of brass or leather. powdered ore is dropped on a moving belt. Magnetic rollers attract magnetic ore contents. nonmagnetic ore particles fall apart from it. and thus separation is carried out.
25) Answer the questions on the following passage.
The minerals from which the metal can be separated economically are called ores.Ores contain many types of impurities such as soil, sand and rocky substances along with the metal compounds. These impurities are called gangue. Metals can be extracted from their ores by means of various methods of separation. The process of extraction of metal in pure state from the ores is also a part of metallurgy. Ores are taken out from the mines and the gangue is usually separated from the ore at the site itself by various methods.Then the ores are carried out to the place where metals are produced. Here metals are extracted in pure form. Then metals are further purified by different methods of purification.this entire process is called metallurgy. Most metals being reactive do not occur in nature in free state but are found in combined state as their salts such as oxides,carbonates, sulphides and nitrates.however, the most unreactive metals that are not affected by air,water and other natural factors like silver,gold,platinum,generally occur in free state. The compounds of metals that occur in nature along with the impurities are called minerals.
A) What are metals?
Answer: Metals are the minerals mixed with impurities called ores.
B) Which processes are involved in the branch of metallurgy? What is metallurgy?
Answer: Extraction of metals from impurities of minerals and further purification of metals is metallurgy.
C) Which metals are found in free state?
Answer: Gold, Silver, and Platinum are metals found in free state.
D) In what form are metals found in composite?
Answer: Metals occur in a combined state as their salts such as oxides,carbonates, sulphides and nitrates.
A) What is soil impurity?
Answer: Metals that occur in nature along with the impurities are called minerals and are mixed in soil in the form of minerals.
26) Explain the difference between a bayer’s process and a hall’s process by explaining the bayer’s process?
Answer: In Bayer’s process aluminum ore is heated in the presence of caustic soda. In Hall’s process aluminum ore is heated in presence of aqueous sodium carbonate product obtained is a water soluble sodium aluminate.
Aluminium ore is called Bauxite. Bauxite has several impurities like Silica SiO2, Ferric Oxide Fe2O3, Titanium Oxide TiO2. These impurities present in bauxite are removed using Bayer’s process or Hall’s process.
Bayer’s Process: Solution of sodium aluminate is aluminate in mixed with water and is diluted final product is concentrated alumina obtained by calcination.
Al2O3.2H2O(s) + 2NaOH (aq) → 2NaAlO2 (aq) + 3H2O (l)
27) What is corrosion? Give solutions by giving examples of corrosion?
Answer: Components of atmosphere like moisture, oxygen carry out oxidation of metals and damage the metal surface is called corrosion. Iron reacts with the air moisture and turns into a reddish surface layer. Copper metal reacts with carbon dioxide in air and forms a green layer.
28) Observe the figure and write the answers to the following questions.
A) Write the name of the reaction shown in the following figure.
Answer: esterification
B) Write the above chemical reaction in the form of a balanced equation.
Answer: C2H5OH + CH3COOH CONC H2SO4 —–> CH3COOC2H5 + H2O
C) Write the name of the product produced in the above reaction, write a use.
Answer: Ethyl Ethanoate
D) Write the name of the catalyst used in the above reaction.
Answer: Concentrated Sulphuric Acid
29) Write the answers to the questions by observing the following figure.
A) Write the chemical reaction shown in the figure above in the form of a balanced equation.
The given diagram shows the decomposition reaction of Calcium carbonate.
B) Write the name of the gas coming out of the large test tube in the above chemical reaction.
C) Why do small bubbles of lime appear in the small test tube?
D) What is the change in color of lime net?
Answer:
a) Balanced Equation of reaction is as follows:
2CH3COOH(aq) + Na2CO3(s) —> 2 CH3COONa(aq) + H2O(l) + CO2
b) The gas coming out of the large test tube in the above chemical reaction is carbon dioxide (CO2)
c) The carbon dioxide gas passes from bent tube to the small test tube of lime water. Therefore, bubbles are seen in the small test tube.
d) Lime water turns milky.
30) Write the names of India’s satellite series and launchers?
Answer: INSAT and GSAT are India’s satellite series and PSLV and GSLV are India’s satellite launchers.
31) What is a satellite launcher? Explain the external layout of a satellite launcher made by ISRO (I.S.R.O.) with diagrams.
Answer: Satellites are placed in specific orbit at a certain height above the earth’s surface. With the help of a satellite launcher satellite taken to that height. PSLV i.e Polar satellite launch vehicle is the satellite launcher made by ISRO. It is made up of four stages. At the top position the satellite is placed. First to fourth stages have alternate solid and liquid fluid containers. Fuel from each stage is burned and lifts up. At a certain specific height each stage gets detached. Initial thrust to the satellite launcher is provided by a set of six rockets. This engine set uses solid fuel.
. To put the satellite in its proper orbit at specific height above the earth’s surface, the satellite is taken to that height using a satellite launcher.
32) Read the following paragraphs and write the answers.
Mars is the second closest celestial object to Earth after the Moon. It was sent to Mars by many nations. But since the campaign was difficult, almost half of the campaigns were not successful. But we have done something that we should be proud of. Launched by ISRO in November 2013 at a very low cost, the Mars rover was launched into Mars orbit in September 2014 and gained important information about the surface and atmosphere of Mars.
A) After the moon, which is the closest celestial object to the earth?
Answer: Mars is the closest celestial object to the earth after the moon.
B) When did ISRO launch Mars spacecraft?
Answer: ISRO launched the Mars spacecraft in September 2014.
C) What important information did ISRO’s Mars rover get?
Answer: Mars rover collected information on Mars surface and surface of mars.
D) Explain that specific velocity does not depend on the mass of the satellite?
Answer: Specific velocity can be also called critical velocity , it is the minimum velocity provided to the satellite to place it in a specific orbit.
Yes, critical velocity is independent of the mass of the satellite.
critical velocity mathematically expressed as, √{GM/(R+h)}
where, G= Gravitational Force, M= Mass of the Earth, R=Radius of earth and h=satellite height from the earth surface. Thus, critical velocity is independent of satellite mass, it depends on mass of earth.
33) Explain the need and importance of space missions.
Answer: Person living far away in another country can contact each other within seconds. One can easily search the information on the internet we need. Advance warnings about natural calamities are issued by the meteorological department because of the satellites. Satellites are used to carry out air surveillance by the military of any nation. Fossil reserve and mineral contents of the earth can be explored. Above mentioned are advantages of space missions. Space technology and space mission is most needed technology for developed as well as developing nations.