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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.
| 8401. |
State and explain the Joule.s law ofheating. |
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Answer» Solution :The quantity of heat generated in a CONDUCTOR when a current flows through it is (1) DIRECTLY proportional to the square of current for a given resistance and the TIME-interval for which the current flows. (2) directly proportional to the resistance for a given current and time- interval. (3) directly proportional to the time for which the current flows through the resistor fora given resistance and current, Le., `H =i^2Rt` This mathematical expression (equation) is called the Joule LAW of heating. From the Joule.s law of heating it is clearthat the heat (H) produced in a conductor due to ELECTRIC current depends upon (1) the current (IJ (2) the resistance (R) of the conductor (3) the time (t) for which the current flows. |
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| 8402. |
Do you think some force is constantly acting on the moon ? |
| Answer» Solution :There is a FORCE CONSTANTLY acting on the MOON known as centripetal force | |
| 8403. |
What is meant by spectrum of white light?How can we recombine the component of white light a prism has separated them.? Draw a diagram to illustrate it. |
Answer» SOLUTION :The coloured patternVIBGYOR formed by a prism by splitting the incident WHITE light is called a SPECTRUM, By having two prism inverted to each other,.one can recombine the light to GET white light again 
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| 8404. |
Assertion (A) : Glass is optically denser than water. Reason (R) : An optically denser medium is that in which speed of light is comparatively less. |
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Answer» Both (A) and (R) are TRUE and (R) is correct explanation of the assertion. |
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| 8405. |
Name the device used to protect the electric circuits from overloading and short circuiting. |
| Answer» Solution :A fuses are used to PROTECT CIRCUITS from OVERLOADING and short CIRCUITING. | |
| 8406. |
For the same of incidence in media P,Q and R, the angle of refractive are45^(@), 35^(@) and 15^(@) respectively. In which medium will the velocity of light be minimum? Give reason for your answer. |
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Answer» SOLUTION :For the same angle of incidence in media P,Q and R the angles of REFRACTION is MINIMUM for the MEDIUM R. Hence velocity of light would be minimum in R a `c/v=(sin i)/(sin r)` |
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| 8407. |
Explain how sexual reproduction givesrise to more viable variation than asexual reproduction. How does this affect the evolution of those organism that reproduce sexually. |
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Answer» Solution :Sexual reproduction cause more viable variation DUE to the following reasons: Error in copying of DNA, which are not highly SIGNIFICANT . Random segregation of paternal and maternal chromosomes at the time of gamete formation. Exchange of genetic material between homologous chromosomes during formation of gamets. Accumulation of variations OCCURED due to sexual reproduction over generation after generation of selection by nature created wide diversity. In case of sexual reproduction, only the very small changes due to inaccuracies in DNA copying pass on to the progency. Thus offsprings of a sexual reproduction are more or less genetically similar to their parents so it can be concluded that evolution in sexually reproducing organisms PROCEEDS at a faster PACE than in sexually reproducing organisms. |
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| 8408. |
The principle of working of a motor is |
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Answer» there is a magnetic field around a current carrying conductor. |
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| 8409. |
The potential difference V is proportional to the current I, the graph between V and I is a. . . . .. . . . . . |
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Answer» STRAIGHT LINE |
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| 8410. |
You are given kerosene, turpentine and water. In which of these does the light travel fastest ? |
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Answer» SOLUTION :We FIND the values of refractive index of given substances as : For keronsene N = 1.44, turpentine n = 1.47 and water n = 1.33 As refractive index of water is least out of three substances, hence as per relation `upsilon = (C)/(upsilon)`, it is clear that speed of light is maximum in water. So, light TRAVELS fastest in water. |
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| 8411. |
What determines the rate at which energy is delivered by a current? |
| Answer» Solution :ELECTRIC power of a CIRCUIT determines the RATE at which energy is delivered by a current. | |
| 8412. |
Explain the structure and functioning of the human eye. How are we able to see nearby and distant objects ? |
Answer» Solution :The human eye is the most preious and complex organ of the human body. It is a natural camera and a combination of several optical instruments which helps us to see the beautiful world around us.  The parts of the human eye are : * Cornea - The transparent thin membrane at the front of the eye through which light enters. Its outer part is CONVEX in shape and bulges outwards. * Iris - Dark MUSCULAR ring-shaped diaphragm behind the cornea which controls the size of the pupil. * Pupil -A hole in the middl of the iris which controls the amount of light entering the eye. In bright light, iris CONTRACTS the pupil and in dim light, iris expands the pupil so that suitable around of light can enter the eye to view the objects clearly. * Crystalline lens - Soft and flexible jelly-like material made up of protein which can change shape to finely focus lighton the retina. It acts as a convex lens. * Ciliary muscles - They help eye lens to change its shape and hence its focal length according to distance of th object to be viewed. * Suspensory ligaments - Extend from eye lens to ciliary muscles and hold the eye lens in proper position. * Retina - A delicate membrane behind the eye which acts as screen on which the images are formed. it has a number of light-sensitive cells .rods. [which sense intensity of light] and .cones. [which sense colours]. * Aqueous humour - Watery liquid which fills the space between eye lens and the cornea. * Vitreous humour - Transparent jelly-like substance which fills the space between eye lens and the retina. * Blind spot - Small region at the junction of retina and the optical nerve. There are no light-sensitive cells in this region and hence vision is not possible. Working of the human eye : Light rays from the objects enter through the cornea and pupil into the eye lens. The pupil regulates the amount of light entering into the eye. The outer surface of the cornea and eye lens together converge the light rays on the retina to form a real inverted image of the object. The light-sensitive cells of the retina get activated and generate ELECTRICAL signals which are sent to the BRAIN through the optical nerve. The brain interprets and processes these signals so that we are able to .view. the erect object. While viewing a distant object, theciliary muscles relax and the eye lens becomes thin, thereby increasing its focal length. While viewing a nearby object, the ciliary muscles contract, making the eye lens thicker and decreasing its focal length. Thus, we are able to see the nearby and distant objects clearly. |
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| 8413. |
If two lenses of focal lengths f_(1) and f_(2) are kept in contact with each other, state the formula for the focal length of the combination . If P_(1) and P_(2) are the powers of these lenses, state the formula for the power of the combination. |
| Answer» SOLUTION :If POWERS of TWO lenses are `P_(1) and P_(2)` then the power of their combination is GIVEN by the formula `P = P_(1) + P_(2)`. | |
| 8414. |
Cybercrimes : |
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Answer» Solution :(1) No personal information should be shared on the phone, especially the details of bank account, Aadhaar card, PAN card, credit card or debit card number, etc. Cheating persons by using this information is a greatest cybercrime. (2) If PIN of any debit or credit card is known to a stranger, he or she can make fraudulent transactions. (3) The PIN number and CVV number should be kept total secret. Otherwise, the bank transactions are done using PIN without the knowledge of consumers. (4) In on-line purchases, many a TIMES consumers are cheated. In this, the consumers are shown superior items on websites but actually the inferior ones are SOLD to them. (5) 'Hacking of information' is done by some programmers in which the confidentialinformation about government, INSTITUTES and companies is obtained from internet with the HELP of computer programs. (6) Fake Facebood accounts are opened and false informationis displayed there. This is for harassing girls or financially exploiting others. (7) In internetpiracy, written LITERATURE, software, photos, videos, music, etc. of other persons are misused or illegally used. (8) Misuse of electronic media sending derogatory messages, spreading vulgar pictures and provocative statements is also a cybercrime. Very rapid exchange of information through media like email, Facebook and Whatsaap takes place these days. But we have to take care about leaking of our own important information. However, when our personal information and phone numbers are automatically spread and reached to fraudulent people, then they commit malpractices which can hinder the function or shut of the cell phones or computers. All these are cybercrimes which are also indicative of mental health. |
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| 8415. |
Vacuum cleaner, Flashlight, Toaster, Television |
| Answer» SOLUTION :FLASHLIGHT. It is powered by BATTERIES, while the others are powered by household ELECTRICITY. | |
| 8416. |
A nuclear power plant is working normally. What would you do if the reactor core suddenly got too hot ? |
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Answer» |
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| 8417. |
(a) Define Hydrated salt. (b) Define the term: solution. |
| Answer» Solution :The number of water molecules found in the CRYSTALLINE substance or SALTS is CALLED water of crystallization. Such salts are called HYDRATED salts. | |
| 8418. |
Why do the values of least distance of distinct vision and angle of vision change with person and age ? |
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Answer» Solution :1) The ciliary muscle which attached with eye lens HELPS the eye to change its focal length by changing RADII of CURVATURE of eye lens. 2) When the eye is focussed on a distant object, the ciliary muscles are relaxed so that the focal length of eye lens has its maximum value which is equal to its distance form the RETINA. 3) the working of ciliary muscles in eye changes fromperson to person. 4) So, the values of least distance of distinct vision and ANGLE of vision changes with person and age. |
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| 8419. |
The strength of the magnetic field around an infinite current carrying conductor is : |
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Answer» More at the ENDS than at the centre |
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| 8420. |
In a domesticelectric ciruit -wiring, withwhichwiredo we connect a fuse ? |
| Answer» SOLUTION :THELIVE WIRE. | |
| 8421. |
What are the products obtained when zinc metal is allowed to react with dilute solution of sodium hydroxide? |
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Answer» SOLUTION :When zinc metal is allowed to react with DILUTE solution of sodium HYDROXIDE, sodium zincate is formed and hydrogen GAS is evolved. `Zn+2NaOH to Na_(2)ZnO_(2)+H_(2)` |
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| 8422. |
If 80 g steam of temperature 97^@C is released on an ice slab of temperature 0^@C, how much ice will melt? How much energy will be transferred to the ice? When the steam will be transformed to water? |
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Answer» Solution :GIVEN : Latent HEAT of MELTING the ice = `L_"melt"`=80 cal/g Latent heat of vapourization of water =`L_"VAP"`=540 cal/g Solution:mass of steam =`m_"steam"`=80 g Temperature of steam=`97^@C` Temperature of ice = `T_"ice"=0^@C` Heatreleased during conversion of steam of temperature `97^@C` into water of temperature `97^@C= m_"steam" xx L_"vap"` =80 x 540 ...(i) Heat released during conversion of water of `97^@C` into water at `0^@C = m_"steam" xx DeltaT xx c` =80 x (97-0) x 1 = 80 x 97 ...(ii) Total heat gained by the ice = 80 x 540 + 80 x 97 ... from equation (i) and (ii) = 80 (540 + 97 ) = 80 x 637 = 50960 cal Some mass of the ice `(m_"ice")` , will melt due to this heat gained by the ice, then, `m_"ice"xxL_"melt"`=50960 cal `m_"ice" xx 80`=50960 `m_"ice"`=637 g Thus, 637 g ice will melt and 50960 cal will be given to the ice . |
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| 8423. |
Atmospheric pressue can be measured by using |
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Answer» lactometer |
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| 8425. |
What are Newton's law of motion ? Which one is called universal law? |
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Answer» Solution :(1) Newton's first LAW of motion : An OBJECT continues to remain at rest or in a state of uniform motion along a straight LINE unless an external UNBALANCED force acts on on it. (2) Newton's second law of motion : The rate of change of momentum is proportional to the applied force and the change of momentum occurs in the direction of the force. (3) Newton's third law of motion : Every action force has an equal and opposite reaction force which acts simultaneously. |
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| 8426. |
When the angle between two vectorsof equal magnitude is 2pi//3, prove that tha magnitude of the resultant is equal to either. |
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Answer» <P> Solution :`R=(P^(2)+Q^(2)+2PQ cos THETA)^(1//2)``=(P^(2)+P^(2)+2P.P "cos"(2pi)/(3))^(1//2)` `=[2P^(2)+2P^(2)((-1)/(2))]^(1//2)=P` |
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| 8427. |
Why are the video-clips of parents threatening or hitting the children not stayding as per their wish or domestic helpers beating the children, very common on social media nowadays ? |
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Answer» Solution :a. Several parents tend to physically punish their children in ourder to make them focus mor on STUDIES and get higher grades and marks. b. They have extremely high expectations from their children and are READY to spend more money to educate them by sending them to private tutions and classes. C. In many houses, children are left along with the servents, who might not be to affectionate towards them. it generally happens in houses where both mother and father are ways from home DUE to work. d. These servants cannot take case of the psychologicval needs of the children, get irritated listening to their daily demands and tend to BEAT them. |
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| 8428. |
Judge the equivalent resistance when the following are connected in parallel: 1 Omega and 10^(6)Omega |
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Answer» Solution :(a) Less than 1`Omega` (but approximately `1 Omega`) (b) less than `1 Omega` (but approximately `1 Omega`) EXPLANATION: When RESISTORS are CONNECTED in parallel. the equivalent resistance is less than the least resistance (here in both the cases it is 1 `Omega`) connected in the combination. Here , `R_1 = 1Omega and R_2 = 10^6 Omega` The equivalent resistance `R_p` of the parallel combination is given by. `1/R_P = 1/R_1 + 1/R_2` `:. R_p = (R_1 xx R_2)/(R_1 + R_2)` `= (1 xx 10^6)/(1 + 10^6)` `= (1000000)/(1000001) ~~ 1 Omega` |
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| 8429. |
One gram of ice at 0^@C is added to 5 gram of water at 10^@ С. Final temperature of the mixture is |
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Answer» `-5 ^@C ` `1 XX (-80) + 5 xx 1 xx 10 ` ` = (1 +5 ) xx 1 xx DELTA theta ` ` or- 3 0 = 6Deltatheta ` ` or DELTATHETA- 5 ^@C ` |
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| 8430. |
State whether the following statement is true or faclse : convex mirror can be used as a shop security mirror ? |
| Answer» SOLUTION :1 | |
| 8431. |
In which of the following cases of motion, the distance moved and the magnitude of displacement are equal ? |
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Answer» if the car is moving on straight road |
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| 8432. |
A person wants to read a book placed at 20 cm whereas the near poit of his eyes is 50 cm. Calculate the power of the lens required. |
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Answer» SOLUTION :Given y = -20 cm, v = -50 cm, P = ? Using lens FORMULA, `f = (u v)/(v-u) = ((-20) xx (-50))/(-50 + 20) = -33.33 cm` `:. P = (100)/(f) = (100)/(-33.33) = -3D` |
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| 8434. |
Give examples of inexhaustible resources at global level. |
| Answer» Solution :Solar energy, wind POWER, TIDAL power, RAINFALL and EVEN atomic energy. | |
| 8435. |
Draw a diagram to show that formation of image of a distant object of myopic eye. How this defect can be remedied ? |
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Answer» Solution :The person is suffering from myopia or short sightedness. Myopia or short-sightedness. In normal eye, the far point is at infinity. The rays coming from distant object (at infinity) gets focussed on retina. In TURN, the retina conveys the massage to brain VIA optical nerve. Causesof Defect in Defective Eye. The defect arise due to either : (i) the length of eye ball is elongated (becomes longer than normal) (ii) the focal lengthof eye lens has decreased. Due to either or both the causes, the eye is not ABLE to focus the rays from distant object are retinal . Focussing is thereat a point O in front of retina . Image formed on retina is , blurred. The defective eye is however able to focus the object UPTO its far point . Correction of Defect We have observed that the defective eye has not been able to focus less inclined rays but has been able to focus more inclined rays. To correct this defect, a concave or a divergent lens of appropriate focal length is placed in front of the eye so that parallel rays coming from infinity appear, afterrefraction through the lens , to come from the far point when eye isunaccommodated. Theseparallel rays from a distant object shall be brought to focus upon the retina. Obviously, the focal length of such a lens is equal to the distance of the far point from the eye . 
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| 8436. |
How is the critical angle related to the refractive index of a medium ? |
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Answer» |
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| 8437. |
State the characteristics of theparallel combination of resistors. |
| Answer» SOLUTION :Characteristics of a PARALLEL combination . of resistors are as FOLLOWS: | |
| 8438. |
Maximum 1 A current can pass through a bulb haVing resistance 100 Omega. What will be the power of this bulb? |
| Answer» SOLUTION :`P = I^2R = (1)^2 (100) =100W` | |
| 8439. |
A body of mass 1 kg falls from a height of 5 m How mcuh energy does it posses at any instant ?(Take g=9.8 m s^(-2)) |
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Answer» Solution :GIVEN ,m=1 kg.h=5m,g =9.8 m `s^(-2)` The ENERGY possessedby the BODY at any INSTANT =Intitial POTENTIAL energy of the body |
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| 8440. |
It was a bright, sunny day in the morning when the classes started in the school. Suddenly dark clouds appeared in the sky. Due to this the classroom became quite dark. The teacher asked a student to switch on all the lights in the classroom. (a) Why did the teacher ask for all the lights to be switched on ? (b) What was the size of the pupil of the eyes of the students : (i) before the clouds appeared ? (ii) when classroom became quite dark ? (iii) when the lights were switched on ? (c) In which of the above mentioned three situations, the students will feel glare in their eyes and why ? (d) What values are exhibited by the teacher in this case ? |
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Answer» Solution :(a) The TEACHER asked all the lights in the classroom to be switched on because seeing the blackboard writing in dim light put a lot of strain on the eyes of the students. (b) (i) Before the clouds appeared, there was sufficient light in the classroom due to which the size of PUPIL of eyes was SMALL. (ii) When classroom became quite dark, the light was dim, due to which the size of pupil of eyes was very large. (iii) When the lights were switched on, the light was bright and hence the size of pupil of eyes became small again. (C) The students will feel glare in their eyes when the lights are switched on in the dark classroom. This is because the size of pupil of eye is large in the dark room. So, when lights are switched on, then suddenly too much light enters the eyes (due to large size of pupil) causing the glare in the eyes. (d) The values exhibited by the teacher are (i) General awareness or Knowledge (that it is NECESSARY to study in sufficient light to keep the eyes healthy, and (ii) Concern for the students (that studying in dim light can harm the eyes of students). |
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| 8441. |
In an experiment to study the refraction of light through a rectangular glass slab, a student measured the angle of incidence, angle of refraction and the angle of emergence, The student lost the reading of angle of incidence but noted the readings of angle of refraction to be 35^(@) and angle of emergence to be 65^(@). The angle of incidence is likely to be : |
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Answer» `45^(@)` |
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| 8442. |
During transformation of liquid phase to solid phase, the latent heat is .. .. ........... . |
| Answer» SOLUTION :GIVEN out | |
| 8443. |
What is atmospheric refraction? Use this phenomenon to explain the following natural events. (i) Twinkling of stars. (ii) Advanced sun-rise and delayed sun-set. Draw diagrams to illustrate your answers. |
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Answer» Solution :Atmospheric refraction : Refraction of light caused by the earth.s ATMOSPHERE due to change in the REFRACTIVE indices of different layers. (i) Twinkling of stars : Stars are distant point sized source of light. The path of the rays of light coming from the star goes on varying due to atmospheric refraction slightly. Thus apparent position of the stars fluctuates and the amount of star light entering the eye flickers giving the twinkling effect.  (ii) Advanced sun-rise : When the sun is slightly below the HORIZON, light rays coming from the sun travel from the rarer to denser layers of AIR. Because of atmospheric refraction of light, light appears to come from a HIGHER position above the horizon. Thus sun appears earlier than actual sunrise. Delayed sunset : Same reason as similar refraction occurs at the sunset. |
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| 8444. |
A bodyof mass 5 kg is taken a height 5 m to 10 m .Find the increase in its potential energy (g=10 m s^(-2)) |
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Answer» Solution :Given ,m =5 kg , `h_(1)`=5M,`h_(2)`=10 mg,g=10 m `s^(-2)` Increase in POTENTIAL ENERGY =mg `(h_(2)-h_(1))` =`5xx1-xx(10-5)-250 J` |
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| 8445. |
Albert Einstein used corpuscular theory to explain |
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Answer» `E=mc^(2)` |
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| 8446. |
A piece of wire of resistance 10 ohm is drawn out so that its length is increased to three times its original length. Calculate the new resistance. |
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Answer» Solution :`""`Specific resistance `(rho)=(RA)/l` `""R=(rhol)/A` When the length is increased by three and then the AREA of CROSS SECTION is reduced by three `"Resistance of wire R"=10Omega` `"New resistance" R^(.)=(rho(3l))/((A//3))` `""=rho(3l) times 3/A` `""R^(.)=(9rhol)/A` `""R^(.)= 9 times R=9 times 10` `""R^(.)=90 Omega` |
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| 8447. |
A current of 2A flows through a 12 V bulb then find resistance. |
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Answer» SOLUTION :Given: V=12V, 1=2A V=1R `R=(V)/(1)=(12)/(2)` `R=6Omega` |
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| 8448. |
The mass numbers of four elements A, B, C and D are 2, 20, 135 and 235, respectively. Which one of them will be most suitable to make : (i) an atom bomb, and (ii) a hydrogen bomb ? |
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| 8449. |
List two forms of energy where solar energy manifests itself in ocens. |
| Answer» SOLUTION :TIDAL ENERGY / sea-wave energy / OCEAN THERMAL energy. | |
| 8450. |
Why all apples fall vertically downward and not at an angle to the vertical. Why do they not fly off in a horizontal direction ? |
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Answer» SOLUTION :(i) The force with which earth attracts any object is directed towards the centre of the earth. (ii)At any GIVEN position of a falling object, the direction from the falling object to the centre fo the earth is vertically downward. Hence, any object on earth will fall vertically downward and not at an angle to the VERTICAL , nor will the object FLY off in a horizontal direction . |
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