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InterviewSolution
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.
| 5052. |
(a) What is meant by 'power of a lens' ? (b) State and define the SI unit of power of a lens. (c) A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are placed in close contact with each other. Calculate the lens power of this combination. |
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Answer» Solution :(a) and (b) - For power of lens and its SI UNIT, see Point Numbers 42 under the heading "Chapter At A GLANCE". (C) Focal length of convex lens `f_(1) = + 25 cm = + 0.25 cm` `therefore` Power of convex lens `P_(1) = (1)/(f_(1) "in m") = (1)/(0.25 m) = + 4.0 D` Again focal length of concave lens `f_(2) = - 10 cm = - 0.1 m` `therefore` Power of concave lens `P_(2) = (1)/(f_(2) "in m") = (1)/((-0.10)m) = -10.0 D` `therefore` Power of the lens combination `P = P_(1) + P_(2) = + 4.0 - 10.0 = - 6.0 D` The -ve sign signifies that the lens combination behaves as a concave (diverging) lens. |
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| 5053. |
Find which has greater resistance, 1 KW heater or a 100 W tungsten bulb, both marked for 230 V. |
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Answer» <P> SOLUTION :`P_(1)=1KW=1000W,P2=100W,V=230V``P_(1)=(V_(2))/(R_(1))rArrR_(1)=(V_(2))/(P_(1))=(230xx230)/(1000)=52.9Omega` `P_(2)=(V_(2))/(R_(2))rArrR_(2)=(V_(2))/(P_(2))=(230xx230)/(100)=529` `therefore` 100 W BULB has more resisstance. |
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| 5054. |
The frequencyof alternating current in India is 50 Hz. What does it mean? |
| Answer» Solution :In India, the alternating CURRENT changes DIRECTION after every `(1)/(100)` SECOND, so the frequency of alternating current is 50 HZ. | |
| 5055. |
A body is pivoted at a point. A force of 10N is applied at a distance of 30cm from the pivot. Calculate the moment of force about the pivot. |
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Answer» SOLUTION :GIVEN= F=10N, r=30cm=0.3 CM Moment of FORCE `=F times r=10 times 0.3=3N m` |
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| 5056. |
A point positive charge is brought near an isolated conducting sphere Fig. The electric field is best given by |
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Answer» FIG (i) |
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| 5057. |
Name the two components of central nervous system in humans. |
| Answer» Solution :These two COMPONENTS are (i) the Brain (II) SPINAL CORD | |
| 5058. |
The phenomenon of electromagnetic inductions is : |
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Answer» the process of charging a body |
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| 5060. |
If heat is exchanged between a hot and cold object, the temperature of the cold object goes on ............ due to gain of energy and the temperature of the hot object goes on ............ due to loss of energy. |
| Answer» SOLUTION :INCREASING, DECREASING | |
| 5062. |
Give Scientific reasons . For electric power transmission, copper or aluminium wire is used. |
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Answer» Solution :1.For electric POWER transmission, copper or aluminium wire is used as they are good conductors of electricity. 2. They have high melting and boiling points, so that they do not melt easily. 3. They ALSO have very low resistivity, so that the heat produced while the electricity PASSES through the conductor is less. 4. Therefore, for electric power transmission, copper or aluminium wire is used. |
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| 5063. |
A copper calorimeter of mass 100g and temperature30^(@)Ccontains water of mass 200 g and temperature30^(@)C. If a pieceof ice of mass 40g and temperature 0^(@)Cis added to it,what will be the maximum temperatureof the mixture ? [c( copper ) = 0.1 cal // g.^(@)C,c ( water ) =1 cal //g.^(@) C , L = 80 cal //g ] |
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| 5064. |
State Faraday's laws of electromagnetic induction. |
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Answer» Solution :`I^(st)`LAW : WHENEVER a magnetic field linked with a conductor changes, an induced e.m.f. of is generated in the conductor. `II^(st)` Law : The magnitude of induced e.m. of is directly proportional to the RATE of change of magnetic field. |
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| 5065. |
Phon is unit of |
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Answer» WAVELENGTH |
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| 5066. |
A …………… is a specializec pictorial representation used to trace the path of ray of light. |
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| 5067. |
A potential difference of 100 V is applied across an electric bulb marked 40 W. 200 V. The power consumed in the bulb is . …………….. . |
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Answer» <P>100W `:.`Resistance of the FILAMENT of the bulb, `R = V^2/P = ((200)^2)/(40) = 1000Omega` Now, POWER consumed in the bulb, `P = V^2/R = ((100)^2)/1000 = 10 W` |
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| 5068. |
If the time-displacement graph of a particle is parallel to the-axis, the velocity of the particle is |
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Answer» INFINITY |
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| 5069. |
Disasters certainly affect the economy of the country. This effect is always relative to both the disaster as well as the economy. Thus, if the intensity of the disaster isvery high, the effect on the economy will be more. Also if the preparadness of the government agencies to deal with the disaster is poor it affects the economy further. For example, if anyport is destroyed, there will be long lasting effects on economy because of the huge expenses on its reconstruction. Disasters also affect social leadership. If the local leadership is not strong enougth, citizens become confused affecting their participation in rescue and rehabilitation activities. Administrative problems also arise during the disaster, wherein if local governing bodies get affected by disaster, the related departments are not able to address the issues of disaster efficiently. This can further lead to collapsing of the entire system. Based on the given paragraph answer the following questions. i. Does a disaster affect the economy of a nation? Given example. ii. How is the effect fo the disaster on the economy relative? iii. How can a disaster lead to collapse of a system? |
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Answer» Solution :i. Yes, disasters do affect the economy of a NATION. For example, if a port is detroyed in disaster, there will be a HUGE impact onteh economy because huge expenses are involved on its reconstruction. ii. A. The higher theintensity of the disaster, greater is its EFFECT on the economy. b. Also, the greater the PREPARADNESS of the government agencies the less the effect of disaster on economy. Thus the effec of disaster on economy is relative. iii. a. When the local GOVERNING bodies asre affected by the disaster, administrative problems arise. b. Further, the related departments are also not able to address the issue properly. This finally leads to the collapsing of the entire system. |
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| 5070. |
Why fossil fuels are to be conserved? |
Answer» Solution :(i) .Scratch. is a software USED to create animations, cartoons and games EASILY. Scratch. on the other hand, is a visual programming LANGUAGE. (iii) Formation of fossil fuels is a very slow PROCESS and takes very long period of TIME for renewal. Hence to be conserved. |
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| 5071. |
State two factors on which the strength of an electric current in a given conductor depends? |
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Answer» Solution :From the ohm.s LAW, `"current I"= (V("Potential difference"))/(R("resistance"))` It is obvious from this RELATION that ... (1) ` I prop V `if = R = CONSTANT and (2)I prop `1/R"if " V` = constant From (1), if potential difference across the ends of a conductor is doubled, the current flowing through it ALSO gets doubled. If the potential difference is HALVED, the current also gets halved. From (2), if the resistance is doubled, the current gets halved. If the resistance is halved, the current gets doubled. Thus, the strength of an electric current in a given conductor depends on two factors: (1) Potential difference across the ends of the conductor and (2) Resistance of the conductor. |
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| 5072. |
What will be the effect on yourself and surrounding, if any accident-like disaster occurs during the sports on playground or in school? |
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Answer» Solution :(i) All the STUDENTS including me will be under mental stress and anxiety. , (ii) Teachers will be under stress. (iii) School functioning and education will be temporarily DISRUPTED. (iv) Anger of people against School MANAGEMENT, if the disaster is not handled properly. (v) Analysis by school management on the cause of the ACCIDENT in playground in school. (vi) It will affect children.s ABILITY to perform well in exams |
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| 5073. |
A convex lens forms a real image of pencil at a distance of 50 cm from the lens . The image formed is of the same size as the object . Find the focal length and power of the lens. At what distance is the pencil placed from the lens ? |
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Answer» SOLUTION :DATA : Convex lens ,v=50 cm `M=-1 ,F= ?"h"_(1)=?, U=?` `M=-1=v/u` `therefore u=-v=-50cm"" `(object distance) The pencil is PLACED at 50 cm from the convex lens . `1/f=1/v-1/u=1/(50cm)-1/(-50cm) =(2)/(50 cm)` `therefore f=(50cm)/(2)=25 cm` `P=1/f=1/(25cm)=1/(0.25 m)=4 D` The power of the lens =4 D. |
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| 5074. |
An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and the nature of the image formed. |
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Answer» Solution :The ray diagram is drawn below Here f = + 10 cm, u = -25 cm and H = 5 cm. From lens formula `(1)/(V) - (1)/(u) = (1)/(f) rArr (1)/(v) - ((1)/(-25)) = (1)/(10) rArr (1)/(v) = (1)/(10) - (1)/(25) = (3)/(50)` `therefore v = 50//3` cm = 16.7 cm. The image is real and is formed at a distance of 16.7 cm from the lens on opposite side. As magnification `m = (h.)/(h) = (v)/(u)` `therefore""(h.)/(5 cm) = (+50 //3)/(-25) = - (2)/(3)` `rArr""h. = (-2)/(3) xx 5 = -(10)/(3)` cm Hence, the image is inverted and diminished in size. 
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| 5075. |
If the linear momentum is increased by 50%, then kinetic energy will increase by |
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Answer» 0.5 `K^(1)=2.25` % increase `=(DELTAK)/Kxx100=125%` |
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| 5076. |
The angle of refraction is same for different colours. |
| Answer» Solution :Correct Statement : The ANGLE of refraction is DIFFRACTION is DIFFERENT for different COLOURS. | |
| 5078. |
Asserion: Temperature is the average kinetic energy of the molecules of a substance. Reason: Temperature determines the flow of heat. |
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Answer» both the assertion and the REASON are trueand the reason is the CORRECT EXPLANATION of the assertion. |
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| 5079. |
Energy from various sources is considered to have been derived from the sun. Do you agree? Justify your answer. |
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Answer» Solution :Yes. Wind energ Warm air rises up and cold air settles down. Similarly, due to uneven heating of the earth.s surface by the SUN RAYS at Dwo different adjoining Places, a pressure difference is created and wind is produced. Wave energy: Strong winds are generated due to the sun and the waves are generated by strong winds blowing across the sea. Ocean thermal energy The difference in TEMPERATURE berween the water at the surface and water at depth in SEAS and oceans is due to the sun. Energy from fossil fuels: Fosil fuels [coal, petroleum, ete.] are tormed when large plants and ancient creatures are buried DEEP inside the earth.s crust under the effect of a lot of pressure and heat. Solar energy: The phenomenon of photoelectric effect generation of electricity by light) is possible only in the presence of sun. Blomass: Plants convert the solar energy into chemical energy with the help of inorganic substances [i.e., air, water, etc.] These plants are consumed by plants and animals to produce wastes from which energy is obtained. Energy from flowing water: Water from sea and rivers evaporates and falls at different places of the earth as snow and rainfal. This water collected in a dam, when allowed to flow, rotates the turblne of a generator and electricity is produced. |
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| 5081. |
what is irreversible reactions? |
Answer» SOLUTION :
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| 5082. |
If the speed of rotation of the armature of a generator is doubled, how does it affect [i] the maximum emf produced and [ii] the frequency of the emf ? |
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Answer» Solution :i] The MAXIMUM emf gets boubled. II] The FREQUENCY of the emf gets DOUBLED. |
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| 5083. |
In figure two positive charges q_(2) and q_(3) fixed along the y-axis, exert a net electric force in the +x-direction on a charge q_(1) fixed along the x-axis. If a positive charge Q is added at (x,0), the force on q_(1). |
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Answer» shall increase along the POSITIVE x-axis |
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| 5084. |
In Porifera the water is taken in through……… andgiven out through ………… . |
| Answer» Solution :In Porifera the WATER is taken in through OSTIA and GIVEN out through OSCULA. | |
| 5085. |
The linearmomentum of a system of particlesis alwaysconserved . |
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Answer» |
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| 5086. |
Which of the following pairs of physical quantities does not have same dimensional formula? |
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Answer» Work and torque |
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| 5087. |
(a) Compare the speed of light of wavelength 4000 Å (i.e., violet light) and 8000 Å (i.e. red light) in vacuum. (b) How is the refractive index of a medium related to the speed of light in it and in vacuum or air ? |
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| 5088. |
A person needs a lens of power - 5.5 dioptres for correcting his distant vision. For correcting his near vision he needs a lens of power + 1.5 dioptre. What is the focal length of the lens required for correcting (i) distant vision, and (ii) near vision? |
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Answer» <P> Solution :(i) For distant VISION`P=-5.5D` `f=(1)/(P)=(1)/(-5.5)=-0.182m` `f=-18.2cm` (II) For distant vision `P=1.5D` `f=(1)/(P)=(1)/(1.5)=0.667m` `f=66.7cm` |
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| 5089. |
Explain the process of nutrition in Amoeba. |
Answer» Solution :Amoeba is an important protozoa found in fresh water. If feeds on microscopic plants and animals present in water. The mode of nutrition in amoeba is holozoic and the process of obtaining food by amoeba is called phagocytosis. The different processes involved in the nutrition of amoeba are :  i) Ingestion : Ingestion is the process of taking food in the BODY. Amoeba is a unicellular animal, so it doesn.t have a mouth for ingestion of food. Amoeba ingests the food by encircling it by forming pseudopodia, when the food is COMPLETELY encircled the food is engulfed in the FORM of a bag called food vacuole. ii) Digestion : Digestion is the process of breaking the large and insoluble molecules in to small and water soluble molecules. In amoeba several digestive enzymes react on the food present in the food vacuoles and break it down into simple and soluble molecular. iii) Absorption : The food digested by digestive enzyme is then obsorbed in the cytoplasm by the process of diffusion. While the undigested food remains in the food vacuole. If a large AMOUNT of food is obsorbed by amoeba, the exess is stored in the cytoplasm in the form of glycogen and lipids. iv) Assimilation : During this step the food obsorbed by the cytoplasm is used to obtain energy, growth and repair. This process of utilizing obsorbed food for obtaining energy, repair and growth is called assimilation. v) Egestion : When, a sufficient amount of undigested food gets collected in the food vacuole it is THROWN out of the body by rupturing cell membranes. The process of removal of undigested food from the body is called egestion. |
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| 5090. |
Mention twowaysto increases the strength of the magnetic field of a current- carryingsolenoid . |
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Answer» Solution :Two ways to increases the strenght of the magneticfieldof a current- carryingsolenoid : (1) Increasingthe NUMBEROF turnsof the solenoid . (II) Increasing the CURRENTTHROUGH the solenoid . |
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| 5091. |
Give the examples of each. hobbies to reduce stress. |
| Answer» Solution :Gardening, BIRD watching, REARING domestic animal, going for a WALK with PET, etc. | |
| 5092. |
State and explain Fleming's right hand rule. |
Answer» Solution :Stretch the thumb, the index finger and the middle finger of the RIGHT hand in such a way that they are PERPENDICULAR to each other, n this POSITION, the thumb indicates the direction of the MOTION of the conductor, the index finger the direction of the magnetic field, and the middle finger shows the direction of the INDUCED current. 
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| 5093. |
Define electric resistance of a conductor? (b) List two factors on which resistance of a conductor depends. (c ) Resistance of a metal wire of length 1m is 104 Omega at 20^@C. IF the diameter of the wire is 0.15mm, find the resistivity of the metal at that temperature. |
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Answer» Solution :(C )Here length of wire L=1m, resistance R=`104 Omega` and DIAMETER of wire D=0.15mm =`0.15 TIMES 10^-3 m` As per relation `R=(rho L)/A=(4 rho L)/(PI D^2)`, we have Resistivity `rho = (pi D^2 R)/(4 L)=(22 times (0.15 times 10^-3)^2 times 104)/(7 times 4 times 1)=1.84 times 10^-6 Omega. m` |
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| 5094. |
A washing machine rated 300 W operates one hour/day. If the cost of a unit is Rs. 3.00 , find the cost of the energy of operate the washing machine for the month of March. |
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Answer» Solution :Data : P=300 W, Rs. 3.00 Per unit, t=`1("hour")/("day")xx31` days =31 hours , 1 unit=1 kW`*H` `=1000 W*h`, cost of the ENERGY = ? `=(Pt)/(1 K W *h//"unit")=(300W xx 31 "hours")/(1000 W *h//"unit")` =9.3 units Cost =9.3 units `xx` Rs. 3.00 per unit =Rs. 27.9. The cost of the energy of operate the WASHING machine for the month of March =Rs. 27.9 |
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| 5095. |
How can you determine the value of I when r =90^(@) |
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Answer» Solution :We can determine the value of the critical angle as follows : `""_(1)n_(2)=(SIN i)/(sin r)` For total internal reflection , i= critical angle r=`90^(@)` (SINCE, sin `90^(@)`=1) Extra question `""_(1)n_(2)=(sin i)/(sin 90^(@))=sin i(therefore SIN90^(@)=1)` |
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| 5096. |
Mitali.s mother was cooking in the kitchen for guests. Mitali saw her mother had plugged in microwave, hot plate and food processor on the same plug point. She immediately switched off the plug and removed all the plugs and re-plugged them in separate individual plugs. What happens when we use too many electrical devices plugged in one power point? |
| Answer» Solution : PLUGGING too many DEVICES in ONE power point CAUSES overloading which can lead to electrical FIRE. | |
| 5097. |
A child is sitting at one end of a long trolley moving with a uniform speed v on a smooth horizontal track. If the child starts running towards the other end of the trolley with a speed u (w.r.t. trolley), the speed of the centre of mass of the system will. |
| Answer» SOLUTION :No CHANGE in speed of system as no external FORCE is working. | |
| 5098. |
Mitali.s mother was cooking in the kitchen for guests. Mitali saw her mother had plugged in microwave, hot plate and food processor on the same plug point. She immediately switched off the plug and removed all the plugs and re-plugged them in separate individual plugs. What is the power of a device? |
| Answer» Solution :The power of an electrical device is the amount of ELECTRIC ENERGY USED by it per unit TIME. | |
| 5099. |
(a) Name the major parts of the human brain. (b) Name the part of brain responsible for maintaining the posture and balance of the body. (c) Which tropic movement is responsible for the growth of pollen tubes towards ovules ? |
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Answer» SOLUTION :(a) Major parts of Brain are: (i) FORE Brain, (ii) Mid Brain, (III) Hind Brain, which has further 3 sub parts which are cerebellum, pons and medulla. (B) Cerebellum part of Hind Brain. (c) Chemotropism. |
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| 5100. |
Mitali.s mother was cooking in the kitchen for guests. Mitali saw her mother had plugged in microwave, hot plate and food processor on the same plug point. She immediately switched off the plug and removed all the plugs and re-plugged them in separate individual plugs. What value did Mitali display in the above act? |
| Answer» Solution : MITALI SHOWED the VALUES of awareness and RESPONSIBILITY. | |