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This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 5851. |
State the units of heat . |
| Answer» Solution :UNITS of HEAT `:` JOULE ,erg, calorie, KILOCALORIE. | |
| 5852. |
A person cannot see distinctly object kept beyond 2 m. This defect can be corrected by using a lens of power |
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Answer» `+0.5` D Power,`P=(1)/(f)`(where, f is focal length in metre) `= (1)/(-2)=-0.5D` |
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| 5853. |
A concave lens has focal length 15 cm. At what distance should the object from the lens be placed , so as to form an image at 10 cm., from the lens . Also find the magnification of the lens. |
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Answer» Solution :Given : F = -15 (concave LENS ) v = -10 (virtual image ) Solution :`1/f = 1/v - 1/u` `1/-15 = 1/-10 - 1/u` `1/u = -1/10 + 1/15` `1/u =(-3 + 2)/30` `1/u = -1/30` u = -30 `THEREFORE` OBJECT distance = 30 cm (negative SIGN INDICATES virtual image) M = `v/u` `M=-10/-30` M = `1/3` |
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| 5854. |
Expand OTEC. On what principle is it based ? |
| Answer» Solution :OTEC means OCEAN THERMAL ENERGY CONVERSION. It is based on the temperature gradient between upper and LOWER layers of the ocean. | |
| 5855. |
What type of spectacles should be worn by a person having the defect of myopia as well as hypermetropia? (ii) The far point of a myopic person is 150 cm. What is the nature and the power of lens required to correct the defect? (iii) With the help of ray diagrams, show the formation of image by (i) a myopic eye (ii) correction of myopic eye by using an appropriate lens. |
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Answer» Solution :(i) Spectacle having BIFOCAL lens. (ii) `u=oo, v=-150cm`. Using lens FORMULA, `(1)/(F)=(1)/(v)-(1)/(u)` `rArr""(1)/(f)=(1)/(-150)-(1)/(@) therefore f=-150cm`. `"POWER of lens " P=(1)/(f)=(-100)/(150)` `=0.67D` NATURE of lens : Concave. (iii) 
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| 5856. |
If the net force acting upon the particle is zero, show that its linear momentum remains constant. |
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Answer» <P> Solution :As `F ALPHA (dP)/(dt)`when `F=0, (dP)/(dt)=0,` so P =CONSTANT |
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| 5857. |
Choose the correct option. A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each |
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Answer» TWO REVOLUTIONS |
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| 5858. |
Observe the diagram given and answer the question asked. d. State the corrective measure. Draw a diagram illustrating it . |
Answer» Solution :Convex lens of optimun FOCAL LENGTH should be USED to CORRECT this defect.
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| 5859. |
Hotliquids getcooledfaster____. |
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Answer» Insidehouse in WATER |
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| 5860. |
Whatare permanentmagnet and electromagnent ? Givetwo uses of each . |
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Answer» Solution :Magnets havinga constantmagnetic fieldaroundthem (e.g., a barmagnet ) arecalled permanentmagnets . Permanentmagnets are used in electric generators,SPEAKERS,refrigerator door etc. Materialsbehavingas magnetn only WHENA CURRENTIS passed through a COIL would around thematerial are called electromagnet . Electromagnets are usedin electricbell ,TRANSFORMER , electriccarnes etc. |
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| 5861. |
What is meant by near point and far point of an eye? State their values for the normal human eye. |
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Answer» Solution :The NEAREST point to the eye at which an object is visible distinctly is called the near point. (25 cm). The maximum DISTANCE up to which the NORMAL eye can see THINGS is called the far point (infinity). |
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| 5862. |
Does the PE. of a spring decreases or increases when it is compressed or stretched? |
| Answer» SOLUTION :Incrreases because W.D. on it when it is COMPRESSED or STRETCHED. | |
| 5863. |
An electric lamp, whose resistance is 20 Omega, and a conductor of 4 Omegaresistance are connected to a 6 V battery (see figure). Calculate (a) the total resistance of the circuit, (b) the current through the circuit, and (c ) the potential difference across the electric lamp and conductor. |
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Answer» Solution :( a) The resistance of electric lamp, `R_1 = 20 Omega` The resistance of the conductor connectedin series,`R_2 = 4Omega` Then the TOTAL resistance in the circuit `R = R_1 + R_2` `R_s = 20 Omega + 4Omega =24 Omega` ( b )The total POTENTIAL difference across the two terminals of the battery `V = 6V` Now by the Ohm.s law, the current through the circuit is given by `I = V/R_a` ` = 6 V/24 Omega` `=0.25 A` ( C )APPLYING the Ohm.s law to the electric lamp and conductor separately, we get potential difference across the electric lamp, `V_1 = 20 Omega xx 0.25 A` `= 5V` and, that across the conductor, `V_2 = 4Omega xx 0.25 A = 1V` Note: Suppose, we like to replace the series combination of electric lamp and conductor by a single and equivalent resistor. Its resistance must be such that a potential difference of 6 V acrosS the battery terminals will cause a current of 0.25 A in the circuit. The resistance R of this equivalent resistor would be `R =V/I` ` = 6V //0.25 A` `=24 Omega` This is the total resistance of the series circuit, it is equal to the sum of the two resistances. |
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| 5864. |
For refraction of light through a glass slab the angle of emergence is equal to the angle of incidence. |
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| 5865. |
What is the critical angle of glass? |
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| 5866. |
Distinguish between Conventional and Non-conventional of energy: |
Answer» SOLUTION :
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| 5867. |
Name and state the rule which gives the direction of force experienced by a current carrying conductor placed in a magnetic field. |
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Answer» SOLUTION :Fleming.s Left Hand Rule According to this rule - "Stretch the thumb, forefinger and MIDDLE finger of your left hand such that they are mutually perpendicular to each other. If the FIRST finger points in the direction of magnetic field and the middle finger in the direction of CURRENT, then the thumb will point in the direction of motion or the FORCE acting on the conductor." |
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| 5869. |
The important components of main box are . . . . . . . . .and . . . . . . . . . . |
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| 5870. |
Traffic signals on cross roads are of red colour. Give reason for choosing only this colour. |
| Answer» Solution :Red light suffers least SCATTERING and can be seen even from a larger distance. Due to this special property TRAFFIC signals on cross ROADS are usually of red COLOUR. | |
| 5871. |
Make a diagrant to show how hypcnnctropia is corrected. The near point of a hypermetropia eye is l m. What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is 25cm |
Answer» Solution :A person suflering frorn hypennetropia can see distant OBJECT clearly but faces difficulty in seeing nearby OBJECTS clearly. It happens because the eye lens focuses the incoming divergent rays beyond the retnia This defect of vision is corrected by using a CONVEX lens. A convex lens of suitable power converges the in co1n ing light in such a way that the image is formed on the RETINA, as shown in the following figure The convex lens actually creates a virtual image of a near by object (Nin the figure) at the near point of vision (N) of the person suflering from hypennetropia. The given person will be able to clearly see the object kept at 25cm (near point of the nonnal eye) if the inmge of the object is formed at his near point which is given as 1m. Object distance, u =25m Image distance, v=1m=-100m Focal length , f Using the lens FORMULA `(1)/(v)-(1)/(u)=(1)/(f)` `-(1)/(100)-(1)/(-25)-(1)/(100)` `(1)/(f)=-(1)/(25)-(1)/(100)` `(1)/(f)=(4-1)/(100)` `f=(100)/(3)=33.3=0.33m` W.K.T Power,` P=(1)/(f("inmetere"))` `p=(1)/(0.33)=+3.0D` a convex lens of power + 3.OD is requited to correct the defect |
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| 5872. |
Draw the diagram of the apparatus used in the electrolysis of water. Label the following parts. i) Graphite rod ii) Cathode |
Answer» SOLUTION :
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| 5873. |
Density of mercury = ……………… |
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Answer» `13.6g//"CC"` |
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| 5874. |
Light rays when travelling from air to water bends …………………… . |
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Answer» Solution :LIGHT RAYS when travelling from air to water bend `ul("towards NORMAL")`. When light rays TRAVEL from RARER medium to denser mediumto denser medium obliquely, it bend towards normal as the velocity of light decreasesafter entering into denser medium, i.e. water. |
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| 5875. |
The currentpassing through two separate circuitsof ourhouses is ______A and ______ A. |
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Answer» 5,10 |
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| 5876. |
A lamp is marked 60 W, 220 V. If it operates at 200 V, the rate of consumption of energy will |
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Answer» decrease |
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| 5877. |
Write the reaction for photosynthesis. |
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Answer» Solution :(a) Photosynthesis is a process by which autotrophic organism like GREEN plants algae and chlorophyll containing bacteria utilize the energy from sunlight to SYNTHESIZE their own food. Photosynthesis occur in green parts of the plant such as leaves, stems and floral buds. (b) `6CO_(2)+12H_(2)O underset("Chlorophyll")overset("Light")(rarr)C_(6)H_(12)O_(6)+6H_(2)O+6O_(2)UARR` Carbon DIOXIDE + Water `rarr` Glucose + Water + Oxygen |
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| 5878. |
Two wires of equal length, one of copper and the other of manganin [an alloy] have the same thickness. Which one can be used for i] electrical transmission lines ii] electrical heating devices? Why? |
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Answer» Solution :i] Copper should be used in the transmission LINES because copper is a REALLY GOOD conductor and does not heat the surface like manganin. ii] Whereas manganin is used in ELECTRICAL heating devices because the heat is trapped and results in the heating effect of ELECTRICITY. |
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| 5879. |
Explain the nature and scope of the disaster of flood with the help of six points given belowgt i. Pre-disaster phase ii. Warning phase iii. Emergency phase iv. Rehabiliatation phase v. Recovery phase vi. Reconstruction phase. |
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Answer» Solution :The nature and scope of the disaster of flood is as follows: i. Pre-disaster phase: a. Generally, floods occur in areas around rivers and dams. This GIVES an opportunity to plan for an upcoming flood. b. In the pre-disaster phase, the areas whch repeatedly get flooded every year are kept READY for evacuation in case of emergency. c. The people in adjacent areas as well as the local authorities are trained and prepared for rescue operations in case of such disaster. ii. Warning phase a. In this phase, a check is kept on the level of river WATER. If the river water is observed to be rising rapidly during rains, it is BORUGHT to the notice of the concerned authorities. b. At the saem time, the people RESIDING in nearby villages adn other human settlements are evacuated and shifted to places of higher altitudes away from flood prone areas. Iii. Emergency phase a. This phase occurs when the river water starts overflowing and nearby areas are in danger. b. Quick action by the rescue operations team during this phase can save maximum lives. c. Providing medical assistacne, first aid as well as restoring communication services are also important steps to be taken in this phase. iv. Rehibilitation phase: v. Recovery phase: vi. Reconstruction phase: |
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| 5880. |
What are the methods used by plants to get rid of excretory products? |
| Answer» Solution :PLANTS have completely different strategies for excretion than those of ANIMALS They can get rid of excess water by transpiration. For other wastes, plants use the fact that many of their tissues consists of DEAD CELLS and that they can even lose some parts such as leaves. In many plants waste products may be stored in leaves that all the waste products are stored as resins and GUMS. especially in old xylem. Plants also excrete some waste substances into the soil around them. | |
| 5881. |
What are the limitations of the energy that can be obtained from the oceans ? |
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Answer» Solution :(i) The difference between the water levels of HIGH tide and low tide should be very large which is not possible at EVERY COASTAL area. (ii) Due to salty water, the components of power plant NEED high MAINTENANCE. |
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| 5882. |
Defineresistance. |
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Answer» Solution :(i) The resistance of a conductor can defined as the ratio between the potential difference across the ends of the conductor and the current FLOWING through it. (ii) It is defined as the reciprocal of its resistance (R ). Hence, the conductance .G. of a conductor is given by `G=1/R` Its UNIT is `"OHN"^(-1)`. It is also represented as .mho. |
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| 5883. |
Draw the symbols of the following. Voltmeter |
Answer» SOLUTION :
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| 5884. |
One kilogram force equals to ____________ |
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Answer» 9.8 DYNE |
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| 5886. |
A person cannot see the objects beyond 1 m. The power of a lens required to correct this vision will be |
| Answer» Answer :A | |
| 5887. |
The parallel rays form the top of a distant tree are incident on a concave mirror forming its image on a screen. The diagram which shows the image of the tree on the screen correctly is : |
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Answer» A |
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| 5888. |
What are the environmental consequences of using fossil fuels ? Suggest steps to minimise the pollution caused by various sources of energy including non - conventional sources of energy. |
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Answer» Solution :Fossil fuels have the following environmental effects: (i) Air pollution : Burning of fossil fuels release OXIDES and sulphides in the air and many other harmful gases like carbon monoxide , sulphur dioxide , etc. These cause various health problems and also lead to acid rain which further AFFECTS water and soil RESOURCES. (ii) Greenhouse effect : On burning fossil , a large amount of carbon dioxide is released into the atmosphere. This is a greenhouse gas and does not allow the sun reflected from the EARTH surface to escape into the atmospehre. Thus, increasing the temperature of the atmosphere. This is called greenhouse effect and results in global warming. Following steps can be taken to minimise pollution : (i) Use smokeless appliances. (ii) Use of refined technologyto increase the efficiency of COMBUSTION process and to reduce escape of harmful gases into the atmosphere. (iii) Judicious use of energy. |
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| 5889. |
The first nuclear reactor was built at |
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Answer» KALPAKKAM, India |
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| 5890. |
Whatis the importanceof valuesin theheart ? |
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Answer» Solution :(i) The pea PLANT is self pollinating and so it is very easy to raise pure breeding inviduals (ii) It has a SHORT LIFE span. (iii) It is easy to cross pollinate . (iv) It has deeply defined contrasting characters. (v) The flowers are BISEXUAL. (b) The valves are the muscular flaps, that regulate the flow of blood in a SINGLE direction and prevent backward flow of blood. |
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| 5892. |
Define the conservative and non -conservative forces. Give examples of each. |
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Answer» SOLUTION :Conservation force: e.g., GRAVITATIONAL force, ELECTROSTATIC force. Non-Conservativeforce : e.g, FORCES of friction, viscosity. |
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| 5893. |
Choose the renewable sourcesof energy from the following list : Coal , biogas , sun natural gas |
| Answer» SOLUTION :Renewable SOURCES of ENERGY from the above LIST are Sun and biogas. | |
| 5894. |
Define the following terms :(i) Power of a lens (ii) Principal focus of a concave mirror(b) Write the relationship among the object distance (u), image distance (v) and the focal length (f) of a(i) Spherical lens(ii) Spherical mirror(c) An object is placed at a distance of 10 cm from optical centre of a convex lens of focal length 15 cm. Draw a labelled ray diagram to show the formation of image in this case. |
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Answer» SOLUTION : (i) Power of a lens is a measure of the degree of convergence or divergence of light rays achieved by it. Mathematically, power (P) of a lens is defined asreciprocal of its focal length i.e., P=`1/f` (ii) Principal focus of a concave mirror is a point situated on its principal axis, where light rays COMING parallel to the principal axis of mirror, after reflection, actuallynconverge. (b) (i) `1/v-1/u=1/f` (ii) `1/v+1/u=1/f` (c) A labelled ray diagram is drawn below :  A virtual, ERECT and ENLARGED image is being formed on same SIDE of lens at a distance of 30 cm from optical centre of lens. |
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| 5895. |
A spherical mirror in which reflecting surface is towards the centre of the sphere of which the mirror is a part, is called concave mirror, i.e., reflection of light for this mirror occurs at concave surface or bent-in surface. The rays of light incident on concave mirror in a direction parallel to the principal axis, actually meet at a single point F on the principal axis of the mirror. This point is called principal focus of the mirror. Read the above passage and answer the following questions : (i) Is principal focus of a concave mirror, a real point or a virtual point? (ii) What happens in case of a convex mirror ? (iii) Our teachers and parents advise us to stay focussed. What does it imply? |
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Answer» Solution :(i) The principal FOCUS F of a concave mirror is a real point. This is because the rays of light,on reflection from the mirror meet actually at F. (II) In CASE of a convex mirror, reflection of light occurs at convex surface or the bulged out surface. Principal focus F, in this case is a virtual point, as reflected rays only appear to come from F. (iii) Our parents and TEACHERS advise us to stay focussed. It implies that we CONCENTRATE all our energies at a single `"point"//"problem"` so that we can resolve the same easily. Staying focussed means we do not divert our energies and attention to several things at a time. This would lead us nowhere. Hence, the secret of success is to stay focussed. |
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| 5896. |
What are the advantages and disadvantages of using a solar cooker ? Are there places where solar cookers would have limited utility ? |
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Answer» Solution :Solar cookers have limited utility places which remain cloudy or have longer winters, e.g., hilly areas. Advantages of using a solar cooker. (i) It cooks food without CAUSING any kind of POLLUTION . (ii) It is economical to use solar cooker because nothing is to be paid for using solar energy . (iii) It is EASY to handle solar cooker and there is no chance of any kind of accident. (iv) The nutrients in the food do not get DESTROYED. Disadvantages of using a solar cooker : (i) Solar cooker cannot be used at night and during cloudy weather. (ii) It takes more time to cook food. (iii) The direction of solar cooker is to be changed continuously towards the direction of the Sun. (iv) Solar energy is not available uniformly all the time and at all the places. (v) It cannot be used for making chapattis and for frying PURPOSES. |
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| 5897. |
Can any source of energy be pollution free. Why or why not ? |
| Answer» SOLUTION :No source of energy can be pollution FREE. It is CONSIDERED that SOLAR cells are pollution free However, even their making causes environmental damage indirectly. Also in the case of nuclear energy, there is no ash produced after the fission REACTION. However, it is not totally pollution free. To start the fission reactions approximately `10^7k`temperature is required which is provided by fission reactions, The wastes realeased from fission reactions, are hazardous. Hence no source ofenergy is plollution - free. | |
| 5898. |
A graph is drawn with a force along y-axis and time along x-axis. The area under the graph represent– |
| Answer» Answer :D | |
| 5899. |
(Cultural, agriculture, fire, brain, Cro-Magnon, Homo sapiens, Neanderthal) Evolution of upright man continued in the direction of developing its ………………… for the period of about 1 lakh years and meanwhile he discovered the ………………………. Brain of man, 50 thousand years ago had been sufficiently evolved to the extent that it could be considered as member of the species ........................ . ................... man can be considered as the first example of wise-man. The ............................. man evolved about 50 thousands years ago and afterwards, this evolution had been faster than the earlier. About 10 thousand years ago, wise-man started to practice the ......................... It started to rear the cattle-herds and established the cities. ................... development took place later. |
| Answer» Solution :Evolution of upright man continued in the direction of developing its brain for the period of about 1 lakh years and meanwhile he discovered the fire. Brain of man 50 thousand years ago had been sufficiently evolved to the extent that it could be considered as member of the SPECIES Homo sapiens. Neanderthal man can be considered as the first example of wise-man. The Cro-Magnon man evolved about 50 thousand years ago and AFTERWARDS, this evolution had been faster than the earlier. About 10 thousands years ago, wise-man STARTED to practice the agriculture. It started to rear the cattle-herds and ESTABLISHED the cities. Cultural development took place later. | |
| 5900. |
Whether the places of disasters are known to you? |
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Answer» Solution :a. The PICTURE on the top LEFT represents flood in Mahad of Raigaddistrict of Maharashrtra wherein the bridge bad COLLAPSED and submerged in water. b. The picture on the top right represents a flood situation in Mumbai due to which railway tracks were submerged and rail services were ADVERSELY affected. c. The picture on the bottom left shows a train accident in Harda district of Madhya Pradesh in which two trains passing each other derailed while crossing a railway bridge. This occurred due to flash floods which dislodged the bridge causing track misalignment. d. The picture on teh bottom right represents the destruction caused due to an earthquake in Kautha village of Nanded district of MAHARASHTRA in whichan elevated water tank has collpased. |
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