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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.
| 8651. |
According to the right-hand thumb rule, thmb indicates the direction of |
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Answer» ELECTRIC current |
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| 8653. |
In ________applince, fleminglefthandruleis notused. |
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Answer» electricfan |
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| 8654. |
Which phenomenon of vision is made use of in cinematography? Explain briefly how it is used? |
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Answer» Solution :Persistence of VISION is· made use of in cinematography. It is the ability of an eye to continue to see the imaoe of an e object fora very short duration even after the removal of the object. We are able to see movie pictures in a CINEMA due to the persistence of vision. The still pictures taken by a movie camera are projected on the screen at the rate of about 24 pictures per second. Under these conditions, the image of on retina till the image of the next picture falls on the screen Due to this, the slightly DIFFERENT images of the successive pictures present on the fiIm merge smoothly into one another and give us the feeling of moving images. THUS the principle of persistence of vision is made use of, in the motion picture projection in cinematography. |
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| 8655. |
What does the pattern of field lines inside the solenoid indicate ? How can this field be utilised to magnetise a piece of soft iron ? |
| Answer» SOLUTION :The PATTERN of field lines inside the solenoid indicates that the solenoid is now BEHAVING as a bar magnet with one end behaving as the NORTH pole and the other end as the south pole of the magnet If a piece of soft iron is placed inside the solenoid and a current is passed through the solenoid coil, the iron piece is magnetised and begins to behave as an ELECTROMAGNET. | |
| 8656. |
Plottinga graph for momentum on the X-axisand time on Y-axis . Slope of momentum - time graph gives _________ |
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Answer» IMPULSIVE FORCE |
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| 8657. |
Discuss the beta decay process with examples. |
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Answer» Solution :A nuclear REACTION, in which an unstable parent NUCLEUS emits a beta particle and FORMS a stable daughter nucleus, is called .bela decay., Eg. Beta decay of phosphorous `""_(15)P^(32) to ""_(16)S^(32)+ ""_(1)E^(0)(beta "decay")` |
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| 8658. |
What is buoyancy ? |
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Answer» SOLUTION :BUOYANCY is the upward FORCE that a fluid EXERTS on an less denser than itself. (or) Buoyancy is the abilty of an OBJECT to float in a liquid. |
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| 8659. |
Baking soda is a mixture of : |
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Answer» SODIUM carbonate and acetic ACID. |
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| 8660. |
Despite of various diagnostic tests,a couple could not have a child . In this situation which remedies will you suggest ? |
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Answer» Solution :Despite of various diagnostic tests, a couple COULD not have a child, then they have to resort to anyone of the following measure : (1) IVF : IVF orIn Vitro Fertilization is the technique used when a couple has a problem of either low SPERM count or obstruction in the fallopian ducts. The embryo is formed in the test tube by carrying out fertilization outside the mother's body . Later the embryo is implanted into the mother's uterus. (2) Surrogacy : Women who have problem regarding the IMPLANTATION of the embryo in her uterus, then another woman's help is taken . This woman is called surrogate mother. The implantation of embryo is done in her uterus. (3) Sperm bank or semen bank : If man is havingproblem regarding the sperm production, then donor's sperms are taken from the sperm bank . In sperm bank the sperms are collected and stored without revealing the identity of the donor. |
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| 8661. |
When body is exposed to 600 R, it causes total disease. |
| Answer» SOLUTION :When BODY is EXPOSED to 600R, it CAUSES DEATH. | |
| 8662. |
In cold regions in winter the pipes for water supply break and even rocks crack. |
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Answer» Solution :In COLD regions, in winter, the ATMOSPHERIC temperature falls below `0^@C`. 2. Due to which, the temperature of water starts decreasing below `4^@C`, it expands and its volume increases. 3. Hence, ice forms in these piples and in the rocks, where water GESTS accumulated in rainyseason. 4. This ice does not flow rather it gets accumulated at large volume, this causes expansion in the pipes which CAUSE them break and even the rocks gets CRACKED, because of the same reason. |
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| 8663. |
All vertebrates are chordates but all chordates are not vertebrates. |
| Answer» Solution :All chordates POSSES notochord in some period of their development . All VERTEBRATES also have notochord during embryonic life, which is later replaced by vertebral column . Therefore all Vertebrates are chordated . But some chordates LIKE Urochordata and CEPHALOCHORDATA do not possess vertebral column and hence they are not vertebrates. | |
| 8665. |
Though a hot iron emits radiations , yet it is not visible in the dark, why? |
| Answer» SOLUTION :HOT IRON emits infrared RAYS. These rays are INVISIBLE to the eyes. | |
| 8666. |
What is critical angle and total internal reflection? |
| Answer» Solution :The ANGLE of INCIDENCE for which the angle of refraction is `90^(@)` is called CRITICAL angle. | |
| 8667. |
Why does the outer surface of a beaker containing ice cubes becomes wet in a short while? |
| Answer» Solution :(1) When ice cubes are placed in a beaker, ice starts melting . The heat required for melting is absorbed from the surrounding air and also from the beaker to some EXTENT. Hence, the TEMPERATURE of the airand beaker falls. (2) The capacity of air to hold water vapour depends upon the temperature of the air, and this capacity decreases as the temperature decreases. At a certain LOW temperature, the surrounding air becomes saturated with waterthe surrounding air becomes saturated with water vapour present in it. As the temperature falls further, the air is unable to hold all the water vapour. Hence, the extra water vapour starts condensing on the cold outer surface of the beaker in the form of minut drops. Therefore, the outer surface of the beaker CONTAINING ice cubess becomes wet in a short while. | |
| 8668. |
Name two tissues which provide control and coordination in animals. |
| Answer» SOLUTION :NERVOUS and MUSCULAR TISSUES | |
| 8669. |
Obtain an expression for the centripetal force F acting ona particle of mass m moving with velocity v in a circle of radius r . Take dimensionless constant K = 1 . |
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Answer» SOLUTION :`Fpropm^(a)` `propv^(b)` `r^(c)` `F=km^(a)V^(b)r^(c)` `[MLT^(-2)]=[M]^(a)[LT^(-1)]^(b)[L]^(c)` `[M][L][T^(-2)]=[M]^(a)[L]^(b+c)[T]^(-b)` COMPARING powers of m, L and T `a = 1""b+c = 1"" –2 = –b` `b = –1 "" b = 2` `F=k(MV^(2))/(r)` |
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| 8670. |
When is the force experienced by a current-carrying conductor placed in a magnetic field largest ? |
| Answer» Solution :The force EXPERIENCED by a current-carrying conductor PLACED in a MAGNETIC field is LARGEST when the current-carrying conductor is placed in a DIRECTION perpendicular to that of magnetic field. | |
| 8671. |
Record your observations when a stained a mounted leaf peel is viewed by you under highpower (45xx) microscope. |
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Answer» Solution :(i) The PROCESS (stomatal process) in which stomatal pores are clearly seen. (ii) Each STOMATA has two KIDNEY shaped cells (GUARD cells) having one nucleusand many chloroplasts each. |
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| 8672. |
(a) List four characteristics of the image formed by a convex lens when an object is placed between its optical centre and principal focus. (b) Size of the image of an object by a concave lens of focal length 20 cm is observed to be reduced to (1)/(3) rd of its size. Find the distance of the object from the lens. |
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Answer» SOLUTION :(a) When an object is placed between the optical centre and PRINCIPAL focus of a convex lens, the image formed is virtual, erect and enlarged. Moreover, the image is formed on the same side of lens behind the object. (b) Here magnification of given concave lens `m = + (1)/(3)` and focal length of lens f = - 20 cm As per relation `m = (v)/(u)` for a lens, we get `+ (1)/(3) = (v)/(u) RARR v = + (u)/(3)` Therefore, as per sign convention followed, both u and v are -ve. Using lens formula `(1)/(v) - (1)/(u) = (1)/(f)`, we have `(1)/((-(u)/(3))) - (1)/((-u)) = (1)/((-20)) rArr (-3)/(u) + (1)/(u) = - (1)/(20) rArr - (2)/(u) = (-1)/(20) rArr u = 40` cm So the object is placed at a distance of 40 cm from the lens. |
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| 8673. |
A fish in water sees an object 24 cm above the surface of water. The height of object above the surface of water that will appear to fish is |
| Answer» Solution :32 cm | |
| 8674. |
List any two common methods by which solid wastes of urban areas are disposed off? |
| Answer» Solution :• BURNING in landfills • Composting • RECYCLE • INCINERATION (WASTE TREATEMENT) | |
| 8675. |
Inan experiment , to study the dependence of potential difference (V) on the electric current (I) across a conductor (resistor), ifthe circuit is on for long time, then -select two correct options from the following: (i) Zero error of an ammeter will be changed. (ii) Zero error of a voltmeter will be changed . (iii) Value of a resistance will be changed. (iv) Resistorwill be heated. |
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Answer» SOLUTION :(i) VALUE of RESISTANCE will be CHANGED. (ii) Resistor will be heated. |
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| 8676. |
Gather information about a power plant near your locality by visiting the plant. |
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Answer» Solution :Solar light : A solar light (solar lamp) converts the solar radiation into electrical energy USING the photovoltaic EFFECT. It consists of an LED lamp , solar panel solar controller and a battery. Solar waterheating system : As solar water heating system uses sunlight for waterheating .It consists of a thermal collector which CAPTURES the heat from the sun and uses it to heat the water. Solar COOKER : Solar cooker is a device which can into heat energy. It works on the principle that black surface ABSORBS more heat than whiteor a reflecting surface. |
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| 8677. |
A man weights 60 kg at earth's surface. At what height above the earth's surface weight becomes 30 kg. Given radius of earth is 6400 km. |
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Answer» 2624 km |
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| 8678. |
(a) What do you understandby the tems'direct current' and 'alternatingcurrent'? (b) Namesomesources of directcurrentand some of alternating current. (c ) State an important advantageof alternating currentover direct current. (d) What is thefrequency of A.C. supplyin India ? |
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Answer» |
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| 8679. |
How much energy is given to each coulomb of charge passing through a 6 V battery? |
| Answer» SOLUTION :`W=VxxQ=6xx1=6` JOULES. | |
| 8680. |
Mention any three factors on which the selection of a good source of energy depends. |
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Answer» Solution :(i) POLLUTION FREE and eco-friendly (ii) Easily accessible, EASY to store and transport (III) ECONOMICAL. |
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| 8681. |
Arjun and Ram are students of Class-IX. Both were initially good in studies. After some time, academic performance of Arjun started declining and he became irritable. This change was noticed by his class teacher. While interacting with Arjun she found out that he had six siblings and the whole family lived in a single room. His mother was not able to devote much attention to him and resources were not sufficient. The teacher motivated him to concentrate on his studies and counselled him. Answer the following questions based on the situation described above. (i) What do you think are the factors which are responsible for change in Arjun's behaviour and his poor performance in studies? (ii) How has the Government help in promoting small families? (iii) What values are promoted by the teacher? |
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Answer» Solution :(i) Big families can be ONE of the reasons. Only small family gets GOOD health and education unlike that of a large family. (ii) The Government has initiated the 'Hum do hamare do' PROGRAMME to provide family planning COUNSELLING, etc. (iii) CARING nature, responsible. |
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| 8682. |
A galvanometer is used for …………….. . |
| Answer» SOLUTION :A galvanometer is used for `ul("detecting the pressure of current in a circuit , as well as for some electrical MEASUREMENTS.")` . | |
| 8683. |
What is refraction of light ? |
| Answer» Solution :Light changes it DIRECTION when PASSING from one transparent MEDIUM. This is called the REFRACTION of light. | |
| 8684. |
What will be the equivalent resistance of n resistors each having resistance R when connected in series and parallel separately? |
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Answer» SOLUTION :The EQUIVALENT RESISTANCE for series connection, `R_s = R + R + R +…n` times `R_s =nR` The equivalent resistance for parallel connection, `1/R_P = 1/R + 1/R + 1/R … n` times `=n/R` `:. R_p = R/n` |
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| 8685. |
In an electric field, electric potential at a point is 10V. How much work has to be done to bring 0.5 C electric charge from infinite distance to that pOint? |
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Answer» 0.5J |
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| 8686. |
Ionising power of B rays.... |
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Answer» 100 times GREATER than `alpha` RAYS |
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| 8687. |
Calculate the fall in temperature when a gas initially at 72^@C is expanded suddenly to eight times its original volume. (gamma = 5//3) |
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Answer» SOLUTION :`T_1V_1^(gamma-1)=T_2V_2^(gamma-1)` `T_2=T_1((V_1)/V_2)^(gamma-1)` `=345xx1/4=86.25 K` |
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| 8688. |
Calculate the power of an engine required to lift 10^(5)Kg of coal per hour from a mone 360 m deep (Take g=10 m s^(-2)) |
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Answer» Solution :m=`10^(5)` KG ,g=10 m `s^(-2)` ,h=360 m. t=1 h=60`xx` 60 s=3600 s The work needed in LIFTING a mass m to a height h against the force due to gravity is `W=mgxxh=mgh` and Power P= `("Work done")/("Time taken")=(mgh)/(t)` `therefore P=(10^(5)xx10xx360)/(3600)-10^(5)W=100 kW` Note:In fact,the actuual power of the engine will be MUCH more than 100 kW because (i)some energy will GET wasted in overcoming the force of friction and (ii)the efficiency of the engine will always be LESS than 100% |
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| 8689. |
Draw a ray diagram to show the path of light that enters the glass prism obliquely. Label on it the angle of incidance and angle of deviation. |
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Answer» Solution :To study refraction of LIGHT through a triangular glas prism : (1) Fix a sheet of white paper on a drawing board using drawing pins. (2) Place the GLASS prism on the board with its triangular base lying at the bottom. Trace the outline of the base using pencil. (3) Fix two pins - P and Q - on a line as SHOWN in the figure. (4) Observe the image of P and Q through the face AC. (5) Fix two more pins R and S such that they lie in the straight line containing images of P and Q. (6) Remove the prism and the pins. (7) Label the points where PQ and RS meet the boundary of the prism at E and F respectively. Join PE, EF and FS as shown. (8) Draw perpendicular NN. and MM. to the faces AB and AC of the prism at points E and F respectively. (9) Mark the angle of incidence `angle i`, angle of refraction `angle r` anad angle of emergence `angle e` as shown.  Inference : At face Ab, as the incident ray PE is travelling from rarer medium [air] to denser medium [glass], it is bent towards the normal NN. along EF. At face AC, ray EF gets refracted by travelling from denser to rarer medium. Hence, the emergent ray FS bends away from the normal, towrds the base of the prism. This is different from refraction in a glass slab because, the incidence ray is not parallel to the emergent ray as in the glass slab. |
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| 8690. |
Food web is constituted by |
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Answer» RELATIONSHIP between the organisms and the ENVIRONMENT |
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| 8691. |
Name the two phenomenon involved in the formation of rainbow. |
| Answer» SOLUTION :DISPERSION and REFLECTION of LIGHT. | |
| 8692. |
How is the surgical removal of unwanted pregnancies misused ? |
| Answer» Solution :SURGICAL REMOVAL of unwanted pregnancy is called MTP (Medical TERMINATION of Pregnancy).Because of some social malpractises in our country, female CHILD is unwanted. Hence, some people indulge in female foeticide. | |
| 8693. |
When a disc rotates with uniform angular velocity, which of the following is not true ? |
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Answer» Some of rotation remains same HENCE, `alpha =0` |
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| 8694. |
The particle which is used to induce artificial disintegration is known as __________. |
| Answer» SOLUTION :PROJECTILE | |
| 8695. |
The two types of chain-reaction are _________ and __________. |
| Answer» SOLUTION :CONTROLLED , UNCONTROLLED | |
| 8696. |
What will happen if number of consumers in environment goes on increasing gradually? |
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Answer» Solution :a. If the number of consumers in the ENVIRONMENT goes on increasinggradually , they would be a decline in the number of the prey they feed on. B. A decline in the number of prey would EVENTUALLY result in a decline in the number of consumers due to scarcity of FOOD. Hence, INCREASE in the number of consumers in the environment would cause an imbalance in the ecosystem. |
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| 8697. |
A monatomic gas at a pressure P, having a volume V expands isothermally to a volume 2 V and then adiabatically to a volume 16 V. The final pressure of the gas is ( take gamma=5/3) |
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Answer» Solution :If `P_2`is pressure after ISOTHERMAL expansion, then `P_2V_2=P_1V_1 , P_2=P_1V_1/V_2=PxxV/(2V)=P/2 ` If P3 is pressure after ADIABATIC expansion, then `P_2V_2^(gamma)=P_3V_3^(gamma)` `P_3=P_2 (V_2/V_3)^gamma=P/2((2V)/16)^(5//3) = P/2 (1/8)^(5//3)` `=P/2(1/2^3)^(5//3) =P/2xx1/2^5 =P/64` |
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| 8698. |
Use your brain power! Where does the latent heat go during these transformations? |
| Answer» SOLUTION :The latent HEAT, during these TRANSFORMATIONS, is GIVEN off (released) in the SURROUNDING. | |
| 8699. |
Draw the graph between P and 1//V (reciprocal of volume) for a perfect gas at constant temperature. |
Answer» SOLUTION :
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| 8700. |
Which of the following body allows only a part of the light to pass through it? |
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Answer» Oiled PAPER |
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