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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.
| 1052. |
Current in a circuit flows : |
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Answer» in DIRECTION from HIGH POTENTIAL to low potential |
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| 1053. |
An object of weight 500 N sinks in water. Weight of water overflowed is 50 N. If another object of the same weight floats on water, what is the weight in water? What is the buoyancy? What is the loss of weight in water? |
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| 1054. |
What happens if cathode rays are stopped by a metal ? |
| Answer» SOLUTION :MOVING cathode ray PARTICLES have energy and when they are STOPPED energy is conserved. Into what FORMS can this KE be transformed ? | |
| 1055. |
At what pressure, is Crooke's dark space observed ? |
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| 1056. |
A body of weight W is floating in a liquid. Its apparent weight will be : |
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Answer» EQUAL to W |
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| 1057. |
The motion of a city bus in a heavy traffic road is an example for uniform motion. |
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| 1059. |
Lifting a small stone to a certain height and then dropping it downwards. What could be the reason for the falling of the stone? |
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| 1060. |
Veena's elder sister Rashmi, who is four months pregnant, has come to stay with them for a weak. Veena's mother, Mrs. Nirmala, wanted to take Rashmi to a gynaecologist for a prenatal (before birth) medical check-up. Veena also accompanied them to the hospital. The gynaecologist carried out the required physical examination of Rashmi and then recommended a particular scan to be done. While going to the Imaging Department of the hospital, Mrs. Nirmala said that after the scan is done, she would ask the doctor doing the scan a specific question aboyt the foetus. Veena is a student of class X who has studied the reproductive systems of humans in the class. She could make out what her mother was going to ask the doctor about the developing foetus. Veena asked her mother not to ask any irrelevent question based on the scan to be done and explained the reason for it. Mrs, Nirmala agreed to what Veena had said. After the required scan was done, all of them visited the gynaecologist again. The gynaecologist studied the scan carefully and said that everything was okay. Everyone was happy. While coming back home, Mrs. Nirmala said that instead of going to a far off hospital the same purpose could have been served by setting an X-ray done on Rashmi at the neighbourhood X-ray clinic. Veena did not agree with her mother. She said a firm 'No' to X-ray on Rashmi at this stage. (a) What type of scan was recommended by gynaecologist for Rashmi? Name the machine used for this purpose. (b) Why was the above scan recommended? (c) Describe the principle of working of the scanning machine briefly. What is this technique known as? (d) What do you think was the irrelevent question which Mrs. Nirmala wanted to ask the doctor after the scan was done? (e) Why did Veena tell her mother not to ask such a question? (f) Why did Veena say 'No' to X-ray for Rashmi? (g) What values are displayed by Veena in this episode? |
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Answer» Solution :(a) The gynaecologist recommended 'ultrasound scan' for Rashmi. An 'ultrasound scanner' machine is used for this PURPOSE. (b) The gynaecologist recommended ultrasound scan for Rashmi for the examination of foetus (unborn child) during pregnancy to detct any abnormality in the growth so that necessary steps could be taken to rectify the abnormality (if any) well in time. (c) The ultrasound scanner works on the principle of reflection of sound (or rather principle of reflection of ultrasound). This happens as follows: The ultrasound scanner trasmits ultrasound pulses into the pregnant woman's body and receives echoes formed by the reflection of ultrasound from the foetus inside the uterus. These ultrasound echoes form a picture of the developing baby and DETECT any growth abnormalities, etc. The technique of obtaining pictures of the internal organs of the baby (having different densities) by using echoes of ultrasound pulses is called ultrasongraphy. (d) Mrs. Nirmala wanted to ASK about the sex (boy or girl) of the foetus (unborn child) of Rashmi. (e) Veena knew that there is a law which PROHIBITS doctors to tell the sex or gender of the unbron child. (f) Veena said 'No' to X-ray for Rashmi because X-rays can damage the delicate body cells of the foetus. This is not so in using ultrasound for taking scans. (g) The various values displayed by Veena in this episode are (i) Responsible citizen (in PREVENTING her mother from knowing the sex of unborn child) (ii) Concern for th girl child (because sex determination of foetus can lead to female foeticide), and (iii) Concern for the healthy growth of her sister's unborn child (by not allowing Rashmi to be exposed to X-rays). |
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| 1062. |
(a) Explain the terms 'compression' and rarefactions of a wave. What type of waves consist of compressions and rarefactions? (b) A worker lives at a distance of 1.32 km from the factory. If the speed of sound in air be 330m//s, how much time will the sound of factory siren take to reach the worker? |
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| 1063. |
A metallic sphere of density "5 g cm"^(-3) is projected upward from the bottom of a pond with a velocity "10 m s"^(-1). The velocity of the sphere on reaching "10 m s"^(-1). The velocity of the sphere on reaching the surface of the water is found to be "8 m s"^(-1). Determine the pressure exerted by water at the bottom of the pond. (Neglect the viscous force acting on the sphere). |
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Answer» SOLUTION :Net Force = weight of the OBJECT - upthrust `v^(2)-U^(2)=2as` p=hdg |
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| 1064. |
The number of teeth in the crank wheel and free wheel of a bicycle,connected by a chain are 48 and 24, respectively.Their diameters are 20 cm and 10 cm, respectively. The radius of the rear wheel to which the free wheel is fixed coaxially is 10 times that of the free wheel. If a cyclist pedals the bicycle at tworotations per second, find the speed of the cyclist. |
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Answer» SOLUTION :(i) Relation between length, height of the INCLINED plane and load, effort (ii) Velocity of the cyclist = 12.56 `m s^(-1)` or 45 m `H^(-1)` |
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| 1065. |
Devices which is used to convert high alternating current to low alternating current is ………………… |
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| 1066. |
The Mechanical Advantage of a hydraulic press is 5. The ratio of the distance travelled by the load to the effort is ________ . |
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| 1067. |
A rectangular wooden block has length, breadth and height of 50 cm, 25 cm and 10 cm, respectively. This wooden block is kepton ground is three different ways trun by trun .Which of the following is the correct statement about the pressure exerted by this block on the ground? |
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Answer» the MAXIMUM pressure is EXERTED when the length and BREADTH FORM the base |
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| 1068. |
Give any four illustrations of the kinetic energy. |
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Answer» Solution :ILLUSTRATIONS of kinetic energy are as follows : (1) A bullet fired from the rifle possess kinetic energy and pierces the target. (2) The kinetic energy of WIND is USED in running windmills. (3) Kinetic energy of flowing water is used to provide electricity through hydroelectric power stations. (4) A coconut detached from a coconut PALM FALLS towards the earth and hence it possesses kinetic energy. |
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| 1069. |
The speed of sound in air at 0^@C is nearly : |
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Answer» `1450 MS^(-1)` |
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| 1070. |
It is possible to heat (boil) fluids by convection process in weightlessness condition ? |
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Answer» SOLUTION :(i) Does the volume of the bottle increase on absorbing heat from the surroundings ? Does the mercury in the bottle too expand along with the bottle when heat is absorbed from the surroundings ? Hence, can we avoid expansion of air in the bottle by PLACING some mercury in it Now what is the CONDITION required so that the volume of air in the bottle does not CHANGES ? Is it `Delta V_("mercury")=DeltaV_("bottle")?` Use `Delta V=Vgamma Delta theta` Is `Delta theta` the same for the bottle and the mercury in it ? (ii) `(3)/(1)` |
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| 1071. |
Take water in bucket. Place a tightly closed bottle on it. What do you observe? |
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| 1072. |
From a rifle of mass 4 kg, a bullet of mass 50 g is fired with an initial velocity of 35 m s-1. Calculate the initial recoil velocity of the rifle. |
| Answer» Solution :initial MASS of rifle, m1 = 4 KG Let initial velocity of recoil pf rifle = u1∴ Initial momentum of the rifle = 4 kg × i’. Initial mass of bullet, m2= 50 g\frac { 50 }{ 1000 } = 0.05 kgInitial velocity of bullet v2 = 35 m s-1∴ Initial momentum of bullet = 0.05 kg × 35 m s-1 By the law of conservation of momentum, Momentum of the rifle = Momentum of bullet | |
| 1073. |
The speed of a particle is constant, Will It have acceleration? Justify with an example. |
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Answer» Solution :(i) When a particle is MOVING with a CONSTANT speed along a straight line, it has no acceleration (ii) When a particle is moving with a constant speed along a CIRCULAR path, the velocity changes due to the CHANGE in direction. Hence it has a acceleration. Ex Revolution of EARTH around the Sun. |
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| 1074. |
Does the transfer of energy take place when you push a huge rock with all your might and fail to move it? Where is the energy you spend going? |
| Answer» Solution :When a force acts on an object, work will be done by that force on the object, if the object UNDERGOES a displacement in the direction of the force. The rock does not move, so there is no transfer of energy. However, ONE gets TIRED because the muscular fibres in the BODY do work due to contraction and relaxation. | |
| 1075. |
Explain how bats use ultrasound to catch a prey. |
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| 1076. |
Explain fuse. |
Answer» Solution :A fuse is another safety MECHANISM which works on JOULE heating principle. Fuse is a wire made up of a Nickel and CHROMIUM alloy which has a definite melting point. If current passes through the fuse beyond a particular desiredvalue, the excess HEAT poduced melts the fuse wire, thus the electricalconnectionis cut - off . Fuse has to be kept in tight a ceramic enclosure to avoid the melting heat from PRODUCING fire accidents. 
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| 1077. |
Fill in the blanks As the time interval decreases, rate of change of momentum ………… |
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| 1078. |
What is the angle of dip at the magnetic south of earth is ? |
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Answer» `30^(@)` |
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| 1080. |
In the dams water is stored in the high reservoirs and then made to fall down. This falling water then rotates the turbines to generate electricity. In this energy conversion process can you tell the initial and final energies respectively? |
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Answer» KINETIC and electrical |
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| 1081. |
How does the sound produced by a vibrating object in a medium reach your ears? |
| Answer» SOLUTION :When an object vibrates, it forces the neighbouring particles of the medium to vibrate. These vibrating particles then FORCE the particles adjacent to them to vibrate. In this way vibrations produced by an object are TRANSFERRED till it REACHES the ear. | |
| 1082. |
Calculate the length of a seconds' pendulum at a place where g= 9.8 m s^(-2) |
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Answer» Solution :For seconds. PENDULUM T= 2.0 s, G= `9.8 m s^(-2)` From the RELATION `T = 2pi SQRT(l/g)` length of pendulum `l = (gT^2)/(4pi^2)` `therefore l = (9.8 xx (2.0)^2)/(4xx(3.14)^2) = 0.994 m ` |
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| 1083. |
Which of the following graph represents uniform motion of a moving particle? |
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| 1084. |
A piece of iron of density 7.8xx10^(3)kgm^(-3) and volume 100cm^(3) is completely immersed in water (rho=1000kgm^(-3)). Calculate (i) the weight of iron piece in air (ii) the upthrust and (iii) its apparent weight in water . (g=10ms^(-2)) |
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Answer» Solution :Given : VOLUME of iron piece `=100cm^(3)` `=100xx10^(-6)m^(3)=10^(-4)m^(3)` (i) Weight of iron piece in AIR `=` Volume `xx` density of iron `xxg` `=10^(-4)xx(7.8xx10^(3))xx10=7.8N` (ii) Upthrust `=` (Volume of water DISPLACED) `xx` density of water `xxg` But volume of water displaced = volume of iron piece when it is completely immersed `=10^(-4)m^(3)` `:.` Upthrust `=10^(-4)xx1000xx10=1N` (III) Apparent weight `=` True weight - Upthrust `=7.8-1=6.8N` |
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| 1085. |
Assertion (A) : Pascal's law is the working principle of a hydraulic lift.Reason (R) : Pressure is thrust per unit area. |
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Answer» If both ASSERTION and REASON are true and reason is the correct explanation of assertion. |
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| 1086. |
State Newton's first law of motion. Give two examples to illustrate Newton's first law of motion |
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| 1087. |
Clouds float in atmosphere because of their low.......... |
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Answer» DENSITY |
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| 1088. |
Atwood machine Atwood used the system to prove Netwons laws of motion. Atowood machine consists of two loads of mases m _(1) and m _(2) attached to the ends of a limp of inextensible string as shown in tghe figure 11. The string runs over a pully. FInd the acceleration of each load and tension in the string (m _(1) gt m _(2)) |
Answer» Solution :we know that tension of string always tries to pull te bodies up.  From the FBD of the mass `m _(1),` there exist two forces on the load of mass `m _(1),` one is tension of the string acting in upward DIRECTION and weight of the load `(m_(1) G)` acting in downward direction. The net force on `m _(1) F _(n et) = m_(1) a` `implies m_(1) g -T =m_(1) a ---------------(1)` Thus the net force `(F_(n et))` acting on mass `m _(1)` produces an acceleration .a. in it. When `m _(1)` moves down, `m _(2)` moves up. So the magnitudes of acceleration are same.  From the FBD of mass `m _(2)` `F _(n et) =T - m _(2) g =m_(2)a ----------------(2)` Solving (1) and (2) equations, we get `a = ((m _(1) - m _(2) g)/( m _(1) + m _(2))` ` T = ( 2M _(1) m _(2) g)/( m _(1) +m_(2))` |
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| 1089. |
Food chain begins with |
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Answer» respiration |
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| 1090. |
A girl walks from her house on a straight path to drop a letter in the letter-box. Then she returns to the origin point. Her displacementtime graph is shown in the figure, draw its velocity-time graph. toSlope of the graph OA = Velocity =(100-0)/(50-0)=+2ms^(-1) Slope of the graph AB = Velocity = (0- 100)/(100 - 50) =- 2ms ^(-1) to It is clear from the given displacement-time graph that the girl moves with constant positive velocity v from O to A. At point A for a moment her velocity becomes zero and moves back to origin (her house) at constant negative velocity by changing the |
Answer» SOLUTION :
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| 1091. |
A body weighs W_(1) gf in air and when immersed in a liquid, it weighs W_(2) gf, while it weighs W_(3) gf on immersing it in water. Find (i) Volume of the body (ii) upthrust due to liquid (iii) relative density of the solid and (iv) relative density of the liqudi. |
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Answer» (iii) `(W_(1))/(W_(1)-W_(3))` (iv) `(W_(1)-W_(2))/(W_(1)-W_(3))` |
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| 1092. |
In a single-touch method of magnetization, the end of the steel bar where the magnet leaves develops a polarity opposite to that of the magnet. |
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Answer» True |
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| 1093. |
If a body tied to a spring balance is fully immersed in a liquid, the apparent loss in its weight: |
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Answer» in more in a DENSER LIQUID |
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| 1094. |
A radioactive element ._(Z)X^(4) whose atomic mass is A and atomic number is Z emits an alpha-particle and gamma-rays. What is the atomic number and atomic mass of the newly formed (daughter) atom? |
| Answer» SOLUTION :An `alpha` particle CONSISTS of TWO protons and two neuctron but `gamma` RAYS. They are emitted by the nucleus of an element. | |
| 1095. |
An object of mass, m is moving with a constant velocity v. How much work should be done on the object in order to bring the object to rest? |
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Answer» WORK done on the object = Change in kinetic ENERGY of the object. = Final K.E. - Initial K.E. `=(1)/(2)m(0)^(2)-(1)/(2)MV^(2)` `=-(1)/(2)mv^(2)` |
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| 1096. |
A car is moving with a velocity 20 m s^(-1). The brakes are applied to retard it at a rate of 2 m s^(-2). What will be the velocity after 5 s of applying the brakes ?. |
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| 1097. |
Ram and Shyam were going from Delhi to Agra by car to see Taj Mahal. Ram was to drive the car. Before strating the car, Ram wore a safety device which is mandatory by law. But Shyam did not care to wear this safety device. The speed limit on the stretch of Delhi-Agra highway at which they were driving at the moment was 80 kilometres per hout (80 kmph). Finding the road wide and free, Shyam asked Ram to drive at a high speed of 100 kmph to get a thrill. Ram, however, said no to overspeeding. He told Shyam that speed thrills but kills'. Just then Ram saw a bullock cart, which was going straight on the road till now, taking a right turn a little distance in front of his car. Noticing this, Ram applied the braked suddenly to stop the car quickly and prevent a collision with the bullock cart. Ram was able to stop his car just before it was to hit the bullock cart. When the car stopped suddenly due to emergency braking, Shyam's head hit the dashboard of car in front of him due to which he got a serious head injury. ram immediately took Shyam to a nearby hospital where he was admitted for treatment. Shyam's parents were also informed. Ram, who was driving the car, escaped unhurt. (a) Why did Shyam's head hit the dashboard of the car when the car stopped suddenly due to emergency braking? Explain your answer. (b) Which law of motion is involved in this horrible accident? By which other name is this law sometimes called? (c) Which safety device Shyam was not wearing at the time of accident which could have prevented head injury to Shyam ? (d) What other safety device is increasingly being provided in the cars in India which is also very helpful in preventing serious inhuries during high speed accidents? (e) What values are displayed by Ram in this episode? |
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Answer» SOLUTION :(a) The car was moving at high speed and alongwith car, Shyam's body was also moving at the same speed. When the brakes were applied suddenly and the car came to a stop, then due to its inertia, Shyam's body tended to continue in motion and he was thrown forward violently. Because of this, Shyam's HEAD hit the dashboard of car in front of him causing a serious head injury. (b) Newton's first LAW of motion is involved in this accident. Newton's first law of motion is also somentimes CALLED GALILEO's law of inertia. (c) Shyam was not wearing a seat belt. (d) The provision of 'air bags' in cars in very helpful in preventing injuries during high speed accidents. Air bag is a safety device which inflates rapidly on the impact of collision to protect the occupant of the car in case of an accident. (e) The value displayed by Ram in this episode are (i) Taking safety precautions while driving (by wearing a sent belt) (ii) Obeying rules of the road (by not exceeding speed limit) (iii) Alertness (in being quick to notice the danger of bullock cart and braking immediately), and (iv) Responsible citizen (in taking injured Shyam to hospital immediately). |
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| 1098. |
Name the characteristic which helps us distinguish between a man's voice and a woman's voice, even without seeing them. |
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| 1099. |
Two equal forces, F = 30 N act opposite to each other, at points A and B. The distances between various points is as follows. AO=20cm, OB=50 cm and OC = OD = 25 cm Thebody is free to rotate about 'O', in the plane of the paper. The moment of couple and the moment of the force about 'O' in N m are |
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Answer» 21 For SIMILAR reasons, the moment of the force at D about O is zero. |
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| 1100. |
How are the following derived units related to the fundamental units ? newton |
| Answer» SOLUTION :`KG m s^(-2)` | |
