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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.
| 6951. |
If an electric conductor is moving in a magnetic field or the magnetic field around a stationary conductor is changing, what will happen? |
| Answer» Solution :In both the cases, DUE to change in the INTENSITY of magnetic FIELD NEAR the conductor, current will be induced in the conductor. | |
| 6952. |
When would virtual image be produced by convex lens? Why can virtual image be not obtained on a screen? |
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Answer» SOLUTION :i. When an object is placed between optical centre and focus of the convex LENS, virtual image is produced by the lens. ii. Virtual image in case of lenses is FORMED on the OPPOSITE side of the SCREEN. Hence, it cannot be drawn on the screen. |
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| 6953. |
List any two causes for the failure of sustained availability of ground water. |
| Answer» Solution :i) LOSS of vegatation COVER ii) Pollution from INDUSTRIAL effluents. | |
| 6954. |
Explain in the details of measuring velocity of sound by Echo method. |
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Answer» Solution :Apparatus required: A SOURCE of sound PULSES, a measuring tape, a sound receiver, and a stop watch. PROCEDURE: (i)Measure the distance between the source of sound pulse and the reflecting surface using the measuring tape. (ii) The receiver is also placed adjacent to the source. A sound pulse is emitted by the source. (iii) The STOPWATCH is used to note the time interval between the instant at which the sound pulse is sent and the instant at which the echo is received by the receiver. Note the time interval as .?. (iv)Repeat the experiment for three or four times. The average time taken for the given number of pulses is calculated. Calculation of speed of sound: (i) The sound pulse emitted by the source travels a total distance of 2d while TRAVELLING rom the source to the wall and then back to the receiver. (ii) The time taken for this has been observed to be . Hence, the speed of sound wave is given by: Speed of sound `("Distance travelled")/("Time taken")=(2d)/(t)` |
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| 6955. |
(i) Explain the structure of an atom bomb. |
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Answer» Solution :Principle : `**` Uncontrolled chain reaction `**` RELEASE large amount of energy in short time Structure : `**` Fissile material whose mass is sub-critial `**` Cylindrical fissile material is FIT into void. `**` Cylinder is injected into the void, using conventional explosive `**` Two pieces together to form super - CRITICAL mass, leads to explosion. `**` Tremendous amount of energy is released in the form of heat, light and radiation. `**gamma` radiation, affects the living CREATURES. `**` This type of atom bombs were exploded at Hiroshima and Nagasaki in Japan during Second World War. (ii) `[H^+] = 1.0 XX 10^(-4) m, pH = ?` `pH = -log_(10)[H^+]` `= -log_(10) 1 xx 10^(-4)` `[M^+] = -log_(10)^(1) - log_(10)^(10^(-4))` `= 0 - (-4) log_(10)^(10) "" :. log_(10)^(10) = 1` `pH4`. |
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| 6957. |
How do you connect a volt meter to the circuit ? |
| Answer» Solution :I CONNECTED a VOLT METER to the CIRCUIT in parallel. | |
| 6958. |
Why do stars twinkle ? |
| Answer» Solution :Stars twinkle due to atmospheric refraction of STARLIGHT. As the stars are very far away, they behave as almost point sources of light. On ACCOUNT of atmospheric refraction, the PATH of rays of light coming from the STAR goes on varying slightly, the APPARENT position of the star fluctuates and the amount of starlight entering the eye flickers. As a result of it, sometimes, the star appears brighter and at some other time, fainter. Thus, the stars twinkle. | |
| 6959. |
What are [i] the highest and [ii] the lowest total resistances which can be secured by combinations of four coils of resistances 4Omega,8Omega,12Omegaand24Omega? |
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Answer» SOLUTION :i] For highest RESISTANCE, resistors are CONNECTED in series. `R_(s)=R_(1)+R_(2)+R_(3)+R_(4)=4+8+12+24=48Omega` II] For lowest resistance, resistors are connected in parallel. `1/R_(p)=1/4+1/8+1/12+1/24=(6+3+2+1)/24=12/24=1/2`. THEREFORE, `R_(p)=2Omega`. |
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| 6960. |
State whether thestatements are true or false. A wire with a green insulation is usually the live wire of an electric supply. |
| Answer» Solution :FALSE, because a LIVE WIRE has always red or BROWN INSULATION. | |
| 6961. |
Define optical centre of a spherical lens. |
| Answer» Solution :OPTICAL centre of a spherical lens is a point on its principal axis, a ray of light PASSING through which goes undeviated ALONG its PATH after REFRACTION. | |
| 6962. |
From which ore is aluminium extracted ? What are thestages in itsextraction (give onlynames ) ? |
| Answer» Solution : Aluminium is EXTRACTED from bauxite ` (Al_(2)O_(3))`Stages in the extraction: (i) CONCENTRATION of ORE, i.e,conversion of bauxite into alumina . (ii) Electrolyticreduction of alumina. | |
| 6963. |
The heat produced in a wire of resistance 'X' when a current 'Y' flows through it in time 'Z' is given by |
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Answer» `X^(2)xxYxxZ` |
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| 6964. |
what are real and virtual images? How will you find out whether and image is real or virtual? Can a virtual image be obtained on a screen? |
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Answer» SOLUTION :1. A real image occurs when light rays converge, whereas a virtual image occurs when light rays only APPEAR to converge. 2. When the image is OBTAINED on a virtual image. 3. Real image are always inverted, while a virtual image is a always ERECT. 4. A virtual image cannot be obtained on a screen. |
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| 6965. |
A student draws the following circuit diagrams for the experiment on studying the dependence of current on potential difference (V) across a resistor. Name the puts labelled as A, B, C and D in the dugram. |
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Answer» Solution :M or A = Ammeter, L or B = Resistance, K or C = Voltmeter D = POTENTIAL difference N = Key |
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| 6966. |
You have three equal resistances r. The maximum possible number of different resistance values that you can offer is |
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Answer» 4 |
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| 6967. |
1 atmosphere = ………………N//m^(2). |
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Answer» `1.01xx10^(5)` |
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| 6968. |
A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well,while his father does it in 2 minutes ,(a)compare: (i)the work ,and (ii)power developed by them. (b)How much work rach deos?Take density of water =10^(3) kg m^(-3) and g=9.8 N kg^(-1) |
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Answer» Solution :(a) (i)WORK 1:1 , (II)POWER 2:3 , (b)Work done by each =3.92 kJ |
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| 6969. |
One word is incorrect in the statement . Change it to make the statement correct : Planet Earth has highest number of animals from phylum Echinodermata. |
| Answer» SOLUTION :PLANET Earth has highest NUMBER of ANIMALS from phylum Arthropoda. | |
| 6970. |
High-class varieties of crops have been developed through the technique of transplantation. |
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Answer» |
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| 6971. |
In 1731, Amrita Devi Bishnoi led a group of 363 persons who sacrificed their lives for the protection of : |
| Answer» Solution :Khejri trees | |
| 6972. |
Draw a schematic diagram of a circuit consisting of a battery of three cells of 2V each, a 5Omega resistor, an 8Omega resistor and a 12Omega resistor, and a plug key, all connected in series. |
Answer» SOLUTION :
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| 6973. |
When sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound remain the same. Do you hear an echo sound on a hotter day? Justify your answer. |
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Answer» Solution :n echo can only be heard if it reaches the ear after 0.1 secs. TIME TAKEN `=("Total DISTANCE")/("Velocity")` As on a hotter day, the velocity of sound is more. So if the time taken by the echo is less than 0.1 sec than it WONT be heard. |
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| 6974. |
How much time a satellite in an orbit of height 35780 km above earth's surface would take, if the mass of the earth would have been four times its original mass? |
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Answer» Solution :Given : Height of the SATELLITE above the earth's SURFACE = 35780 km Velocity of the satellite = 3.08 km/sec. To find: TIME (T) Solution:`G=6.67xx10^(-11) Nm^2 // kg^2 , M=4xx6xx10^24` kg (for earth) R=6400 km (for earth) `=6.4xx10^6` m, h=height of the satellite above the earth's surface = 35780 km R+h =6400 + 35780=42180 km = 42180x `10^3` m `THEREFORE v=sqrt((G4M)/(R+h))=sqrt(((6.67xx10^(-11))xx(4xx6xx10^24))/(42180xx10^3 m))= sqrt((4xx40.02xx10^13)/(42180xx10^3 m))` `therefore ` v=6160.489 m/s = 6.16 km/s `T=(2pir)/v =(2pi(R+h))/v=(2xx3.14(6400+35780))/6.16`=43001.68 sec =11.94 hrs. = 12 hrs. (approx .) The satellite will take 12 hrs. to revolve in the orbit. |
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| 6976. |
A concave mirror is used for image formation for different positions of an object. What inferences can be drawn about the following when an object is placed at a distance of 10 cm from the pole of a concave mirror of focal length 15cm ? (a) position of the image (b) size of the image (c) nature of the image Draw a labelled ray diagram to justify your inferences. |
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Answer» Solution :Here u - 10 cm and f = -15 cm. (a) `(1)/(v) = (1)/(f) - (1)/(u) = (1)/((-15)) = (1)/((-10)) = (1)/(30) rArr v = + 30 cm` So, the image is formed behind the MIRROR at a distance of 30 cm from its pole. (B) MAGNIFICATION `m = -(v)/(u) = - (30)/(-10) = +3` Tt means size of the image is 3 times that of the object. (c) The image is virtual and ERECT. Ray diagram is drawn here. 
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| 6977. |
A student performs an experiment on finding the focal length of a convex lens by keeping a lighted candle on one end of laboratory table, a screen on its other end and the lens between them as shown in the figure. The positions of the three are adjusted to get a sharp image of the candle flame on the screen. If now the candle flame were to be replaced by a distant lamp on a far away electric pole, the student would be able to get a sharp image of this distant lamp on the screen by moving : |
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Answer» the SCREEN in the DIRECTION of the LENS or the lens in the direction of the screen |
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| 6978. |
What type of dynamo (a machine for changing otherpower into electric power or a machine to produce electric current ) is used in (i) a bicycle (ii) industry ? |
| Answer» Solution :In a BICYLE DC DYNAMO is used while in industry AC dynamo is used. | |
| 6979. |
To correct defect of nearsightedness and farsightedness,…………… lenses are required. |
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Answer» |
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| 6980. |
Assertion (A) : Electricmotor is amachine which is usedto produced electrical energy . Reson (R) : The law of conservation of energyis obyedin 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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| 6981. |
State the physical quantity which is equal to the ratio of potential difference and curre.,t. Define its SI unit. |
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Answer» Solution :Electrical RESISTANCE, R `=(V)/(I)` The resistance of a CONDUCTOR is said to be one ohm if the potential di.fference applied across its ends is I volt and a CURRENT of 1 A flows through it. Its SI UNIT is ohm `(Omega)` `1 ohm=(1 "volt")/(1 "ampere")` |
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| 6982. |
A ray of light strikes the glass slab at an angle of 90^(@) from its surface. What is the angle of incidence and the angle of refraction ? |
| Answer» SOLUTION :Angle of INCIDENCE .i. and angle of refraction .R. both are equal to zero DEGREE. | |
| 6983. |
Which one of the following is not true? |
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Answer» VERMIFORM appendix |
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| 6984. |
Which alloy is used to prepare the heating element of an electric iron? |
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Answer» Constanton |
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| 6985. |
State the rule to determine thedirection of a (i) magneticfield produced around a straight cocnductor - carrying current, (ii) forceexperienced by a current - carryingstraight conductor placed in a magnetic fieldwhich is perpendicularto it , and (iii) currentinducedin a coil due toits rotation in a magnetic field . |
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Answer» SOLUTION :(i) Right- HAND thumb rule : SEE answer to Q.11 .of Questions andAnswer section. (ii) Fleming.s left - hand rule: See answer to Q.25.of Questions and Answer section . (iii) Fleming.s right-hand rule : See answer to Q.43.of Questions and Answer section . |
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| 6987. |
To form an erect image twice the size of an object by using a convex lens of focal length 20 cm, the object should be placed at a distance 'd' from the optical centre of lens. Here 'd' is |
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Answer» `d lt 20` cm |
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| 6988. |
Find the vector sum of N coplanar forces, each of the magnitude F,when each force makes an angle of 2pi//N with that preceding it. |
| Answer» SOLUTION :RESULTANT FORCE is ZERO. | |
| 6989. |
List any two disadvantages of using fossil fuels. |
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Answer» Solution :(i) BURNING of coal or petroleum products lead to air pollution. (ii) The oxides of C, N and S are RELEASED on burning fossil fuels as acidic oxides. It leads to acid RAIN and affect WATER and soil. |
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| 6990. |
Assertion: Neutrons are the best bombarding particles. Reason: Neutrons are neutral particles. |
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Answer» If both the assertion and the reason are TRUE and the reason is the correct explanation of the assertion. |
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| 6991. |
Which colour deviates minimum during the dispersion of light through a prism? |
| Answer» Solution :Red LIGHT deviates the LEAST during the DISPERSION of light through a PRISM. | |
| 6992. |
Three resistances of 4 Omega,5 Omega and 20 Omegaare connected in parallel. Their combined resistance is : |
| Answer» SOLUTION :`2 Omega` | |
| 6993. |
How does the image formed on retina help us to precieve the object without change in its shape, size and colour ? |
| Answer» Solution :The eye lens forms a real and inverted image of an object on the retina. This retina is a delicate membrane,Which CONTAINS large number of receptors (125 millions) called 'rods' and 'cones'. They receive the light SIGNALS and identify the colour , and the intensity of light. These signals are transmitted to the brain through optic-nerve fibre. The brain interpretsthese signals and finally PROCESSES the information so that we poercieve the object in terms of its shape,size and colour. | |
| 6994. |
Neon shows zero electron affinity due to __________ |
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Answer» stable ARRANGEMENT of neutrons |
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| 6995. |
In which of the following circuits the voltmeter and ammeter are connected properly to veritY the Ohm.s law? |
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Answer»
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| 6996. |
Draw the symbols of the following. Resistace |
Answer» SOLUTION :
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| 6997. |
Critical velocity of satellite depends on ......... . |
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Answer» ORBIT of SATELLITE |
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| 6998. |
The greater is the value of refractive index, the lesser is the bending of refracted ray towards the normal. |
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Answer» |
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| 6999. |
Mr. Sharma, a property dealer, had many expensive appliances at his home like refrigerator, air conditioners, geyser, etc. but he forgot to put earth wire connections to these appliances. One day his younger daughter opened the fridge and suffered a severe electric shock though, she was saved. Answer the following questions based on the situation given above. (i) Why did it happen? (ii) How can one save himself/herself from electric shocks by these electrical appliances? (iii) What values are being neglected by Mr. Sharma? |
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Answer» Solution :(i) This happened because earth WIRE was not USED in the electric appliances. The purpose of earthing is that in case of an insulation failure in some appliance, this wire connected to the metal body will provide a path for the current to flow in the ground. (ii) By providing PROPER earthing in all electrical appliances, connecting electric fuse in CIRCUITS, never touch an electric switch or appliance with wet hands. (iii) Carefulness and vigilance while handling electric gadgets. |
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| 7000. |
What measures would you take to conserve electricity in your house? |
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Answer» Solution :• Switch off FANS and lights when not in USE •Use of solar WATER heating SYSTEM and solar heaters. • Use of fluorescent TUBES or CFL or LED.S • Use more natural light in rooms. |
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