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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.
| 6651. |
Renewable energy is energy produced from sourece that do not deplete or can be replenished within a human's life time. The most common examples include wind, solar, geothermal, biomass, and hydroelectric power. This is in contrast to non-renewable sources such as fossil fuels. Most renewable energy is derived direcetly or indirectly from the sun. Sunlight can be captured directly using solar technologies. The sun's heat drives winds, whose energy is captured with turbines. Plants also rely on the sun to grow and their stored energy can be utilized for boienergy. Not all renewable energy sources rely on the sun. For example, geothermal energy utilizes the Earth's internal heat, tidal energy relies on the gravitational pull of the moon, and hydroelctric power relies on the flow of water. Give the examples of renewable energy. |
| Answer» Solution :WIND, solar, GEOTHERMAL, biomass and HYDROELECTRIC power are some examples of renewable ENERGY. | |
| 6652. |
Renewable energy is energy produced from sourece that do not deplete or can be replenished within a human's life time. The most common examples include wind, solar, geothermal, biomass, and hydroelectric power. This is in contrast to non-renewable sources such as fossil fuels. Most renewable energy is derived direcetly or indirectly from the sun. Sunlight can be captured directly using solar technologies. The sun's heat drives winds, whose energy is captured with turbines. Plants also rely on the sun to grow and their stored energy can be utilized for boienergy. Not all renewable energy sources rely on the sun. For example, geothermal energy utilizes the Earth's internal heat, tidal energy relies on the gravitational pull of the moon, and hydroelctric power relies on the flow of water. What is renewable energy ? |
| Answer» Solution :RENEWABLE energy is energy that is produced from sources which will not GET exhuasted within a HUMAN's LIFE time. | |
| 6653. |
Assertion (A) : Thephenomenonof electromagneticinduction is the production of induced current in a coil placed in a region where the magnetic field changes with time. Reason (R) : Electric motor utilises the phenomenon of electromagnetic induction. |
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Answer» Both (A) and (R) are true and (R) is correct explanation of the assertion |
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| 6654. |
The magnetic field associated with a current-carrrying conductor is in anticlockwise direction. If the conductor was held along the east-west direction, what will be the direction of current through it ? Name and state the rule applied to determine the direction of current ? |
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Answer» |
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| 6655. |
Nameand state the rulewhich gives the direction ofinduced current . |
Answer» Solution :DIRECTIONOF inuced current in a conductor can be knowwith the help of Fleming.s right - hand rule . Stretch the THUMB ,forefingerand middlefinger of righthand sothat theyare perpendicularto each other. Ifforefingerindicates the directionof the magetic fieldand thumb SHOWS the direction of MOTIONOF conductor , thenthe middlefingerwill show the directionof induced current . |
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| 6656. |
If a resistive wire is uniformly stretched, what Will be a change in its resistance? |
| Answer» SOLUTION :Its RESISTANCE will INCREASE | |
| 6657. |
The number of pwople that have cell phones is rapidly growing and so is the number of people that are becoming addicted to their phones. These phones were invented with an intention of making life easier. However, today there are some people who do not know when to turn them off. There are many people around us who are cell phone addicts. There are people who leave their phone ON in the hospital even if it is against the rules because they are afraid they may miss a call. Some phone users send text massages throughout the day while at work when they should be doing their job. These same people will have an anxiety attack if they forget their phones at home and cannot enjoy what they are doing until the phones is back in their hand. As a greater number of children are using cell phones, its addiction is beoming more widespread. According to a study. Japanese children didn't make friends with peers who didn't have the phones. Another study showed that three quarters of Hungarian children owned cell phones. In Italy, a study showed that one quarter of the adolescents had multiple cell phones while 36% of college students surveyed in Great Britain admitted that they could not live without their cell phones. About 7% of the participants from the British study state that they had lost a job or a relationship due to their excessive cell phone use. Based on the given passage answer the follwoing questions. Give examples of different types of cell phone addicts. |
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Answer» Solution :There are SEVERAL cell phone user who do not turn off their phones and are constantly operting them. Some examples of them are as follows: a. People who leave their phones ON even while in hospital which is against the RULES, becomes they might miss an IMPORTANT cell. b. People who send text MASSAGES throught the day while in office when they should concentrate on their work. c. People who get anxiety attack if they forget their phones at home and are not at peace till they get their phones BACK. |
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| 6658. |
The number of pwople that have cell phones is rapidly growing and so is the number of people that are becoming addicted to their phones. These phones were invented with an intention of making life easier. However, today there are some people who do not know when to turn them off. There are many people around us who are cell phone addicts. There are people who leave their phone ON in the hospital even if it is against the rules because they are afraid they may miss a call. Some phone users send text massages throughout the day while at work when they should be doing their job. These same people will have an anxiety attack if they forget their phones at home and cannot enjoy what they are doing until the phones is back in their hand. As a greater number of children are using cell phones, its addiction is beoming more widespread. According to a study. Japanese children didn't make friends with peers who didn't have the phones. Another study showed that three quarters of Hungarian children owned cell phones. In Italy, a study showed that one quarter of the adolescents had multiple cell phones while 36% of college students surveyed in Great Britain admitted that they could not live without their cell phones. About 7% of the participants from the British study state that they had lost a job or a relationship due to their excessive cell phone use. Based on the given passage answer the follwoing questions. What was the initial intention behind inventing cell phones ? |
| Answer» Solution :The INITIAL interntion behind inventing CELL phones was to MAKE LIFE easire. | |
| 6659. |
The number of pwople that have cell phones is rapidly growing and so is the number of people that are becoming addicted to their phones. These phones were invented with an intention of making life easier. However, today there are some people who do not know when to turn them off. There are many people around us who are cell phone addicts. There are people who leave their phone ON in the hospital even if it is against the rules because they are afraid they may miss a call. Some phone users send text massages throughout the day while at work when they should be doing their job. These same people will have an anxiety attack if they forget their phones at home and cannot enjoy what they are doing until the phones is back in their hand. As a greater number of children are using cell phones, its addiction is beoming more widespread. According to a study. Japanese children didn't make friends with peers who didn't have the phones. Another study showed that three quarters of Hungarian children owned cell phones. In Italy, a study showed that one quarter of the adolescents had multiple cell phones while 36% of college students surveyed in Great Britain admitted that they could not live without their cell phones. About 7% of the participants from the British study state that they had lost a job or a relationship due to their excessive cell phone use. Based on the given passage answer the follwoing questions. Give some examples for around the world showing the cell phone addiction of children. |
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Answer» Solution :The examples from around the world showing the cell phone addiction of children are given below: a. Japanese children didn't make friends with peers who didn't have the phones. B. About three quarters of hungarian children owned cell phones. c. ONE quarter of the adolescents in Italy had multiple cell phones. d. `36%` of college STUDENTS in Great Britain admitted that they could not live WITHOUT their cell phones. e. About `7%` of the participants of a British study has lost a job or a RELATIONSHIP due to excessive usage of cell phones. |
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| 6660. |
Explain what is short circuiting and overloading in an electric supply. |
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Answer» Solution :Short circuiting: Whenever live and neutral wires come in contact with each other, the INCIDENT is called short circuiting. In this case, resistance of a circuit decreases to a very small value. The decreasing of resistance increases the current. Due to this increased current, the wires get heated. This extreme heat may cause fire in the building. Overloading: Every supply has a capacity to beara maximum load, i.e., the power that can besupplied has a limit. Sometimes, the number of appliances which are switched on at the same time have power more than the capacity of the LINE. This is called overloading. In this situation, wires of the supply get heated due to extremely LARGE current flowing through them and the circuit may CATCH fire. To avoid this fire, we use an electric fuse in the circuit. |
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| 6661. |
When light ray travels from denser medium to rarer, then it ………………… . |
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Answer» BENDS towards NORMAL |
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| 6662. |
At what temperature the rms speed of oxygen atom equal to rms speed of helium gas atom at -10^(@)C ? Atomic mass of helium =4 Atomic mass of oxygen =32 |
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Answer» SOLUTION :`v_(rms)=[(3PV)/(M)]^(1//2)=[(3RT)/(M)]^(1//2)` Let r.m.s. speed of oxygen is `(v_(rms))_(1)` and of helium is `(v_(rms))_(2)` is equal at TEMPERATURE `T_(1)` and `T_(2)` respectively. `((v_(rms))_(1))/((v_(rms))_(2))=SQRT((M_(2)T_(1))/(M_(1)T_(2)))` `[(4T)/(32xx263)]^(1//2)=1` `T_(1)=(32xx263)/(4)=2104k`. |
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| 6663. |
A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging? |
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Answer» SOLUTION :`P=+1.5D` `F=?` `f=1/P=1/1.5=10/5=0.667m` `f=66.67cm` SINCE f is positive, LENS is convex (converging lens). |
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| 6664. |
Electric Iron, Electric Heater, Geyser, Electric Bell, Electric Oven. |
| Answer» SOLUTION :ELECTRIC bell. It PRODUCES sound, whereas OTHERS are heating devices. | |
| 6665. |
Renewable energy is energy produced from sourece that do not deplete or can be replenished within a human's life time. The most common examples include wind, solar, geothermal, biomass, and hydroelectric power. This is in contrast to non-renewable sources such as fossil fuels. Most renewable energy is derived direcetly or indirectly from the sun. Sunlight can be captured directly using solar technologies. The sun's heat drives winds, whose energy is captured with turbines. Plants also rely on the sun to grow and their stored energy can be utilized for boienergy. Not all renewable energy sources rely on the sun. For example, geothermal energy utilizes the Earth's internal heat, tidal energy relies on the gravitational pull of the moon, and hydroelctric power relies on the flow of water. Which type of energy do we mostly use in India? |
| Answer» Solution :The most USED ENERGY resource is coal, i.e, FOSSIL fuel BASED ENREGY followed by hydroelectric energy. | |
| 6666. |
Renewable energy is energy produced from sourece that do not deplete or can be replenished within a human's life time. The most common examples include wind, solar, geothermal, biomass, and hydroelectric power. This is in contrast to non-renewable sources such as fossil fuels. Most renewable energy is derived direcetly or indirectly from the sun. Sunlight can be captured directly using solar technologies. The sun's heat drives winds, whose energy is captured with turbines. Plants also rely on the sun to grow and their stored energy can be utilized for boienergy. Not all renewable energy sources rely on the sun. For example, geothermal energy utilizes the Earth's internal heat, tidal energy relies on the gravitational pull of the moon, and hydroelctric power relies on the flow of water. Name the renewable sources of energy which are not dependent on sun. What are they dependdent upon? |
| Answer» SOLUTION :Geothermal energy, tidal energy and hydroelectirc power are non-renewable energy resources which are not dependent on sum. Geothermal energy utilizes the Earth's internal heat, tidal energy RELIES on the gravitational PULL of moon, and HYDROPOWER relies on the flow of water. | |
| 6667. |
Renewable energy is energy produced from sourece that do not deplete or can be replenished within a human's life time. The most common examples include wind, solar, geothermal, biomass, and hydroelectric power. This is in contrast to non-renewable sources such as fossil fuels. Most renewable energy is derived direcetly or indirectly from the sun. Sunlight can be captured directly using solar technologies. The sun's heat drives winds, whose energy is captured with turbines. Plants also rely on the sun to grow and their stored energy can be utilized for boienergy. Not all renewable energy sources rely on the sun. For example, geothermal energy utilizes the Earth's internal heat, tidal energy relies on the gravitational pull of the moon, and hydroelctric power relies on the flow of water. Why will energy from fossil fuel be over soon? |
| Answer» SOLUTION :Fossil fuels are exhaustible in their amount. We have been using these EXTENSIVELY in the past 100 years and hence it MAY get over soon. It is a non-renewable resource. | |
| 6668. |
Suppose you have three concave mirrors A, B and C of focal lengths of 10 cm, 15 cm and 20 cm. For each concave mirror you perform the experiment of image formation for three values of object distance of 10 cm, 20cm and 30 cm. Giving reason answer the following. (i) For the three obuject distances, identify the mirror mirrors which wil form form an image of magnification -1. (ii) Out of the three mirrors identify the mirror which would be preferred to be used for shaving puposes/ makeup. (iii) For the mirror B draw ray diagram for image formation for object distances 10 cm and 20 cm. |
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Answer» Solution :`f_(a)=10cm f_(b)=10cm, f_(c)=20cm` `u_(1)=10cm, u_(2)=20cm, u_(3)=30cm` (i) `m=-1` MEANS `u=2f, ` for `Atou_(2)`, for `Btou_(3)` (ii) Mirror B or C- distance should be less than FOCAL erect and magnified image, face is generally kept at a distance more than 10 cm. 
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| 6669. |
How are concave and convex mirrors constructed? |
Answer» Solution : (i) Generally, concave and convex MIRROR are spherical mirrors. (II) Spherical mirrors are parts of a hollow glass sphere like the part B in the figure. (iii) The INNER or outer surface of this part is coated with a shiny substance to PRODUCE spherical mirror. |
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| 6670. |
The element whose atomic number is less than 83 undergoes............... |
| Answer» SOLUTION :INDUCED RADIOACTIVITY | |
| 6671. |
a] Define electric resistance of a conductor. b] List the factors on which resistance of a conductor depends. c] Resistance of a metal wire of length 1 m is 104Omega" at "20^(@)C. If the diameter of the wire is 0.15 mm, find the resistivity of the metal at this temperature. |
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Answer» Solution :a] Resistance is defined as the property of a conductor to resist the flow of charges through it. The resistance of conductor is numerically given as the ratio of potential difference across its length to the current flowing through it. b] There are four factors that influence the resistance in a conductor. Thickness [CROSS sectional area of the wire], length, temperature and RESISTIVITY of the material that is used. Some metals [COPPER, silver] have lower resistivity than others [iron, ALUMINUM]. c] Resistance, `R=104Omega` Length of wire, L = 1 m Diameter of wire, d = 0.15 mm = `0.15xx10^(-3)m` Cross-sectional area of wire, `A=pir^(2)=(pid^(2))/4" ""[becaused=2r]` = `3.14xx((0.15xx10^(-3))^(2))/4=7.06xx10^(-8)m^(2)` `R=(rhoL)/ArArrrho=(RA)/L=(26xx7.06xx10^(-8))/1` `rho=1.8356xx10^(-6)Omegam` Hence, resistivity is `1.8356xx10^(-6)Omegam" at "20^(@)C` |
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| 6672. |
What is water harvesting? List two main advantages associated with waterharesting at the community level. Write two causes for the failure of sustained availability of groundwater. |
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Answer» Solution :Water harvesting is the concept of capture, collection and storage of EVERY drop of water that has fallen on the land in small PITS, lakes, watershed systems, small earthern dams, constructed dykes, sand and limestone reservoirs, ROOFTOP water COLLECTING systems, etc. Advantages associated with water harvesting: (i) It increases the production and income of the watershed community. (ii) It also mitigates droughts and floods and increases the LIFE of downstream dams and reservoirs. Causes for failure of sustained availability of groundwater are: (i) Loss of vegetation cover. (ii) Diversion for high demanding water crops. (iii) Pollution from industrial effluents and urban wastes. |
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| 6674. |
Define one roentgen. |
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Answer» Solution :(a)(i)One roentgen is defined as the QUANTITY of radioactive substance which produces a charge of `2.58xx10^(-4)`coulomb in 1 kg of air under standard conditions of pressure, TEMPERATURE and humidity. (ii)A Nuclear reactor is a device in which the nuclear fission reaction takes place in a self-sustained and controlled manner to produce electricity.  Components of a Nuclear Reactor The essential components of a nuclear reactor are (i) fuel (ii) moderator (iii) control rod (iv) coolant and (v) PROTECTION wall. (i) Fuel: A fissile material is used as the fuel. The commonly used fuel material is uranium (ii) Moderator: A moderator is used to slow down the high ENERGY neutrons to provide slow neutrons. Graphite and heavy water are the commonly used moderators. (iii)Control rod: Control rods are used to control the number of neutrons in order to have sustained chain reaction. Mostly boron or cadmium rods are used as control rods. They absorb the neutrons. (iv)Coolant: A coolant is used to remove the heat produced in the reactor core, to produce steam. This steam is used to run a turbine in order to produce electricity. Water, air and helium are some of the coolants. (v)Protection wall: A thick concrete lead wall is built AROUND the nuclear reactor in order to prevent the harmful radiations from escaping into the environment. |
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| 6675. |
What are the uses of convex mirror ? |
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Answer» Solution :● REAR VIEW mirror ● Reflector of street ight ● Shopping malls and buildings having LONG have convex mirrors ARROUND the CORNER. |
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| 6676. |
Tell me who am I ? What is my class/phylum ? I am male as well as female . I am endoparasite having a coelomate and bilaterally symmetrical body . |
| Answer» SOLUTION :Liver FLUKE or TAPE WORM , phylum : PLATYHELMINTHES . | |
| 6677. |
One mole of a monatomic gas is mixed with 3 moles of a diatomic gas. What is the molar specific heat of the mixture at constant volume? |
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Answer» Solution :For monoatomic gas , `C_(v)=(3)/(2)R`, `N=1` mole For diatomic gas, `C_(v)'=(5)/(2)R`, `n'=3` mole From conservation of energy , the molecular SPECIFIC heat of the mixture is `C_(v)'=(n(C_(v))+n'(C_(v)'))/((n+n'))` `=(1XX(3)/(2)R+3xx(5)/(2)R)/((1+3))=(9)/(4)R` or `C'v=(9)/(4)xx8.31=18.7 J mol^(-1)K^(-1)` |
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| 6678. |
Explain the appplications of convex lenses used in the following instruments. Telescopes |
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Answer» Solution :Conves LENSES are used in the FOLLOWING instruments. Telescopes: A combination of two convex lenses are used in telescopes. An ASTRONOMICAL bodies like planets, stars, etc. Terrestrial telescope is used to STUDY terrestrial objects. |
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| 6679. |
(a) Give two circumstances your answer by drawing labelled ray diagrams for both. (b) Which one of these circumstances enables a concave mirror to be used as a shaving mirror ? |
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| 6680. |
What is meant by trophic level in a food chain ? Construct a terrestrial food chain with four trophic levels. The energy flow in a food chain is always unidirectional. Why |
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Answer» Solution :Each step of level of the food CHAIN forms a trophic level. Organisms at the first trophic level are called AUTOTROPHS. In fact, these are the producers. They fix up the solar energy and make it available for consumers. Grass `rarr` Grasshopper `rarr` Frog `rarr`SNAKE The energy CAPTURED by autotrophs does not revert back to solar system. It passes to the herbivores and from there to the carnivores. The energy lost goes to the ATMOSPHERE. Thus, energy flow from the sun through the producer to the consumer is in one dimension only. This flow cannot be reversed. |
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| 6681. |
A student wants of project the image of a candle flame on a screen 80 cm in front of a mirror by keeping the candle flame at a distance of 20 cm from its pole. (i) Which type of mirror should the student use? (ii) Find the magnification of the image produced. (iii) Find the distance between the object and its image. (iv) Draw a ray diagram to show the image formation in this case and mark the distance between the object and its image. |
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Answer» Solution :(i) CONCAVE MIRROR (ii) `u=-20CM,v=-80CM,m=?` `m=(-v)/u=(-(-80cm))/((-20cm))=-4` (iii) `v-u=60cm` 
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| 6682. |
A child stands at the centre of turntable with his two arms out stretched. The turntable is set rotating with an angular speed of 40 rpm. How much is the angular speed of the child if he folds his back and thereby reduces his moment of inertia to (2)/(3) times the initial value ? Assume that the turntable rotates without friction |
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Answer» Solution :Here `omega_(1) = 40 rpm, I_(2) = 2/5 I_(1)` By the principle of conservation of angular momentum, `I_(1)omega_(1) = I_(2)omega_(2)` or `I_(1) xx 40 = 2/5 I_(1)omega_(2)` or `omega_(2) = 100` rpm. (ii) Initial KINETIC energy of rotation. `2/5 I_(1)omega_(1)^(2) = 2/5 I_(1) (40)^(2) = 800 I_(1)` Net kinetic energy of rotation `2/5 I_(2)omega_(2)^(2) = 1/2 xx 2/3 I_(1) (100)^(2) = 2000 I_(1)` `("NEW K.E.")/("Initial K.E.") = (2000 I_(1))/(800 I_(1)) = 2.5` Thus the child's new kinetic energy of rotation is 2.5 times its initial kinetic energy of rotation. This increase in kinetic energy is DUE to the INTERNAL energy of the child which he USES in folding his hands back frrom the out stretched position. |
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| 6683. |
(a) To construct a ray diagram we use two light rays which are so chosen that it is easy to know their directions after reflection. Use these two rays to locate the image of an object placed between infinity and the centre of curvature of a concave mirror. (b) Draw a ray diagram to show the formation of image of an object placed between the pole and principal focus of a concavemirror. Howwill the nature and size of the image formed change, if the mirror is replaced by a converging lens of same focal length? |
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Answer» Solution :(a) Therays for obtaining image from the MIRROR after reflection are so chosen that it is easy to know their directions after reflection from the mirror. (i) A ray PARALLEL to theprincipal axis, after reflection passes through the focus in concave mirror or appears to PASS through the focus in CONVEX mirror. (ii) A ray passing through the principal focus of a concave mirror or directed towards the principal focus in convex mirror after reflection will emerge parallel to the principalaxis. (iii) A ray passing through the centre of curvature of the concave mirror or directed in the direction of the centre of curvature of the convex mirror is reflected back along the same path after reflection.  `*` When the object is PLACED between infinity and the centre of curvature of a concave mirror. (b)`*` When the object is placed betweenthe pole and principal focus of a concave mirror. `*` If the object is placed between the 'O' and principal focus of a converging lens (convex lens). |
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| 6684. |
(a) Draw magnetic field lines of a bar magnet. "Two magneticfield lines never intersect each other." Why ? (b) An electric oven of 1.5 kW is operated in a dometic circuit (220V) that has a current rating of 5A. What result do you expect in this case ? Explain . or Which is meant by resistance of a conductor ? Name and define its SI units. List the factors on which the resistance of a conductor depends. How is the resistanceof a wire affected if - (i) its length is doubled , (ii) its radius is doubled ? |
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Answer» Solution :(a) Two magnetic field lines do not INTERSECT one another. The direction of magnetic field lines is always from north pole to south pole. If the two magnetic field lines do intersect, it means at the point of intersection the compass needle is showing two different directions which is not possible. (b) Power, `P = 1.5 kW = 1.5 xx 1,000 = 1,500 W` Voltage, `V = 220 V``I = ?` `P = V xxI``implies I = (P)/(V) = (1,500)/(220) = 6.8 A` Now the current drawn by the oven is 6.8 A which is very high but thefuse in this ciruit is only 5A capacity. When a very high current of 6.8A flows through 5A fuse, the fuse wire will get heated too much, melt and break the circui , cutting off the power supply.  The property of a conductor due to which tends to stop the FLOW of current through the conductor is called resistance, SI unit is ohm. When a potential differnece of IV ACROSS a wire gives rise to IA current through the wire, then the resistance is said to be 1 ohm ( 1 `Omega` ) . The resistance of conductor depends on length, thickness, nature of material and temperature of conductor. (i) If length is doubled, then R is doubled because the resistance of a conductor is directly PROPORTIONAL to length. (ii) Resistance of a conductor is inversely proportional to the square of its diameter or AREA of cross-section. This show `R prop (1)/(A) ,A = pi r^(2)` If `r' =2r`, then , `A' = pi r^(2) = pi (2r)^(2)= 4pi r^(2) = 4A` R `= ` Resistance , L `=` Length A = Area, `rho=` resistivity. `R = rho(L)/(A)` If `A'=4A`, then `R'=rho(L)/(A)=rho(L)/(4A)=(1)/(4)R` Therefore, if radius is doubled, the resistance becomes `(1)/(4)` |
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| 6685. |
A Force F acts on a body and displaces it by a distance S in direction at an angle theta with the direction of force ,(a) Write the expression for the work done by the force,(b)What should be the angle between the force and displacement so that the work done is (i)zero ,(ii)Maximum ? |
| Answer» SOLUTION :(a) F S cos `theta` ,(B) (i)`90^(@)` (II)`0^(@)` | |
| 6686. |
The acceleration is produced along the radius is called as ………………………….. |
| Answer» SOLUTION :CENTRIPETAL ACCELERATION | |
| 6687. |
Electricians wear rubber shoes or rubber hand gloves while working . Why ? |
| Answer» Solution :Rubber is a good electrical INSULATOR. It does not ALLOW the current to pass through the electrician.s body and saves FORM electric shocks. | |
| 6688. |
The focal length of a concave mirror is 16 cm. Its radius of curvature is ___________. |
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Answer» |
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| 6689. |
Distance travelled in nth second has the units of |
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Answer» displacement |
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| 6690. |
The device used for producing electric currentis called |
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Answer» generator |
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| 6691. |
A body has an acceleration of -4ms^(-2). What is its retardation? |
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Answer» `-4MS^(2)` |
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| 6692. |
We saw in this chapter that there are four main stakeholders when it comes to forests andwildlife. Whichamong these should have the authority todecide the management of forestproduce ? Why do you think so ? |
| Answer» Solution :The local people who live in or around FORESTS should have the AUTHORITY to decide the managementof forest produce . These people know the practices to use the resources in sustainable MANNER. These peple have been using the forest and WILDLIFE resources since the ancient times without harming or causing any environment damage . However , they should be constantly checked and GUIDED by environmentailsts and ecologists. | |
| 6693. |
Spheres A and B of uniform density have masses 1 kg and 100 kg respectively. Their centres are separated by 100m.(ii) Find the gravitational force on An due to the earth. [M_("(earth)")=6xx10^(24)kg, R_("(earth)")=6400km] |
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Answer» Solution :Data : `m_(1)=1kg, m_(2)kg, r = 100m`, `M=6xx10^(24)kg, R = 6400km=6400xx10^(3)m,` `t=1s, s=1cm=1xx10^(-2)m,` `G=6.67xx10^(-11)N.m^(2)//kg^(2)` `F_(1)=?, F_(2)=?, v_(1)=? , t_(1)=?, v_(2)=? , t_(2)=?` (III) Ignoring VARIATION of acceleration with distance, `v_(1)=u_(1)+at=0+(F_(1))/(m_(1))t=(6.67xx10^(-13)N)/(1kg)xx1s` `=6.67xx10^(-13)m//s` This velocity is directed from A to B. As the separation between A and B decreases, the acceleration of A and hence the velocity of A will increase. Ignoring variation of acceleration with distance, `s_(1)=ut+(1)/(2)at^(2)=0+(1)/(2)(F_(1))/(m_(1))t_(1)^(2)` `therefore t_(1)^(2)=(2m_(1)s_(1))/(F_(1))` `therefore t_(1)^(2)=(2xx1kgxx10^(-2)m)/(6.67xx10^(-18)N)=3xx10^(10)s^(2)` `therefore t_(1)=1.732xx10^(5)s` |
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| 6694. |
Force of buoyancy is equal to the …………… of the object. |
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Answer» APPARENT LOSS of volume |
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| 6695. |
An element 'X' has atomic number 6. Another element 'Y' has 17 electrons in its neutral atom. (a) To which group of modern periodic table to 'X' and 'Y' belong ? (b) What type of bond will be found in the compound. When 'X' and 'Y' combine ? (c) Write the formula of this compound. State reason for your answer in each case. |
| Answer» Solution :X=2,4, Y=2,8,7 (a)Xbelongs to `14^(th)` group, Y belongs to `17^(th)` group , (B) COVALENT bond, (x) `XY_(4)` | |
| 6696. |
The escape vleocity v of a body depends upo (i) the acceleration due to gravity of the planet and (ii) the radius of the planet R. Establish dimesionally the releaitonship betweeeen v, g and R. |
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Answer» Solution :`valphag^(a)R^(B)impliesv=kg^(a)R^(b),Krarr`DIMENSIONLESS proportionality constant `[v]=[g]^(a)[R]^(b)` `[M^(0)L^(1)T^(-1)]=[M^(0)L^(1)T^(-2)]^(a)[M^(0)L^(1)T^(0)]^(b)` EQUATING powers `1 = a + b` `-1=-2aimpliesa=(1)/(2)` `b=1-a=1-(1)/(2)=(1)/(2)` `therefore v=ksqrt(gR)` |
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| 6697. |
IF potential difference across a given conductor is doubled then its electrical resistance is also doubled. |
| Answer» SOLUTION :False- IF potential difference across a GIVEN CONDUCTOR is doubled then in accordance with Ohm law CURRENT flowing through the conductor is doubled but its resistance remains UNCHANGED. | |
| 6698. |
Do lights rays actually pass through a virtualimage ? |
| Answer» SOLUTION :No, they only APPEAR to PASS through a VIRTUAL IMAGE? | |
| 6699. |
Do all solids expand on heating? If not give an example. |
| Answer» SOLUTION :All SOLID bodies do not expand on heating. semiconductor and camphor CONTRACTS on heating. | |
| 6700. |
In question 93, if Suresh were standing unsymmetrically between parallel cliffs, the distance between two cliffs is |
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Answer» 340 m |
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