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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.
| 451. |
What is the reason for capillary depression? |
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| 452. |
Look at the activities listed below. Reason out whether or not work is done in the light of your understanding of the term 'work'. (i) Suma is swimming in a pond. (ii) A donkey is carrying a load on its back. (iii) A windmill is lifting water from a well. (iv) A green plant is carrying out photosynthesis. (v) An engine is pulling a train. (vi) Food grains are getting dried in the sun. (vii) A sailboat is moving due to wind energy. |
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Answer» Solution :(i) Yes. Suma is doing work. She pushes water in the backward direction and the displacement is in forward direction. (II) No. The work DONE by donkey is zero. The force exerted by the donkey in the upward direction is PERPENDICULAR to the horizontal displacement of the load. (iii) Yes. The work is done in lifting the water against the force of gravity. (iv) No. The leaves of PLANT remain at rest during PHOTOSYNTHESIS. (v) Yes. The force applied by the engine and the displacement of the train are in the same direction. (vi) No. Here there is no displacement. (vii) Yes. The work is done by the wind in moving the sailboat. 
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| 453. |
What is a discharge tube ? Explain its construction. |
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| 454. |
Name the characteristic of sound which can distinguish between the 'notes' (musical sounds) played on a flute and a sitar (both the notes having the same pitch and loundness). |
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| 455. |
(a) If a balloon filled with air and its mouth untied, is released with in the downward direction, it moves. Why? (b) An acceleration truck weighing 2000 kg has a maximum acceleration when it is carrying a load of 2000 kg ? |
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| 456. |
A ship sends out ultrasound that returns from the seabed and is detected after 3.42 s. If the speed of ultrasound through sea water is 1531m s^(-1), what is the distance of the seabed from the ship? |
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Answer» Solution :We KNOW, distance = speed `xx` TIME 2D = speed of ultrasound `xx` time `2d=1531xx3.42` `therefore d=(5236)/(2)=2618m` Thus, the distance of the seabed from the ship is 2618 m or 2.618 KM. |
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| 457. |
What quantity does the area of the graph represent ? What is the magnitude of this quantity ? |
| Answer» Solution :The are of the graph `(F xx s)` represents the WORK done (W) by the force in MOVING the body through a distance (s.) W = AREA of the shaded TRIANGLE`= (1)/(2) (base xx height) = (1)/(2) (0.5 m) (275 N) = 68.8 J.` | |
| 458. |
Describe with the help of a diagram, how compression and rarefractions are produced in air near a source of sound. |
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| 459. |
Can electroplating be possible with alternating current? |
| Answer» Solution :Electroplating is a PROCESS where is continuous flow of IONS for the deposistion of COPPER, which is not possible in ALTERNATING current. Therefore, electroplating is possible with DC only, for the sake of perfectness and homogeneity of the electroplating. | |
| 460. |
Faraday's dark space is observed at_____pressure. |
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| 461. |
A man whose mass is 90 kg stands on his feet on a floor. The total area of contact of his two feet with the floor is 0.036 m^(2) ("Take," g= 10 ms^(-2)).How much is the pressure exerted by him on the floor? |
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Answer» Solution : The weight of the man (thrust), `F = MG = 90 kg xx 10ms^(-2) = 900 N` Pressure, ` P = F/A = (900 N)/(0.036 m^(2)) = 25000 ` PA |
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| 462. |
Rubbing of comb with hair…. |
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Answer» CREATES ELECTRIC charge |
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| 463. |
Express the speed 36 km h^(-1) in m s^(-1) . |
| Answer» SOLUTION :36 KM `H^(-1) = (36KM)/(1 h) = (36xx1000 m)/(60xx60s) = 10 m s^(-1)` | |
| 464. |
A longitudinal wave travels at a speed of 0.3 m s^(-1) and the frequency of wave is 20 Hz. Find the separation between the two consecutive compressions. |
| Answer» SOLUTION :`1.5xx10^(-2) m `( or 1.5 CM) | |
| 465. |
What causes sound ? |
| Answer» SOLUTION :SOUND is caused DUE to VIBRATIONS of a body. | |
| 466. |
A ray of light is incident on a plane mirror placed horizontally. When the mirror is rotated through an angle30^(@) the reflected ray is found to be directed along thevertical. Determine the angle of incidence at the initial position of themirror. |
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Answer» Solution :(i) When a PLANE MIRROR is rotated through an angle `THETA`, the reflected ray is rotated through 2`theta`. The initial angle of incidence `i_(1) = i_(2) + r_(2)` When `i_(2) and r_(2)` are the angle of incidence and angle of reflection after rotating themirror. (II) ` 60^(@)` |
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| 467. |
Reveberation of sound is used in . |
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Answer» STETHOSCOPE |
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| 468. |
An object of mass 2kg is thrown in the upward direction with velocity of 3ms^(-1). What would be the maximum potential energy of this object? |
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Answer» `18J` `E_(K)=(1)/(2)mv^(2)` `=(1)/(2)xx(2kg)xx(3ms^(-1))^(2)=9J` |
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| 469. |
Two simple pendulums A and B have equal lengths, but their bobs weigh 50 gm and 100 gm, respectively. What would be the ratio of their timeperiods? Give reasons for your answer. |
| Answer» SOLUTION :`1:1` , Reason : TIME period does not DEPEND on the WEIGHT of the BOB. | |
| 470. |
A current carrying conductro of certain length, kept perpendicular to the magnetic field experiences a force F. What will be the force if the current is increased four times, lengthis halved and magnetic field is tripled? |
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Answer» Solution :`F=1LB=(4I)xx(L//2)xx(3B)=6F` THEREFORE, the forces inreases SIX times |
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| 471. |
"______" is defined as the rate at which the charges move across any cross section of a conductor. |
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| 472. |
Identify the relation between first pair and completethe second Honey : Viscous liquid Kerosene : _______ |
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| 473. |
Find out reasons for the situations When a running bus is suddenly stopped, passengers standing in the bus show a tendency to fall forward |
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| 474. |
In each of the following a force, F is acting on an object of mass, m. The direction of displacement is from west to east shown by the longer arrow, observe the diagrams carefully and state Wheather the work done by the force is a negative, positive or zero. |
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Answer» Solution :Case (i) In the direction of FORCE acting on the BLOCK is PERPENDICULAR to the displacement. Therefore, work done force on the block will be zero. Case (ii) In this case, the direction of force acting on the block is in the direction of force acting on the block is in the direction of displacement. Therefore, work done by force on the block will be POSITIVE. Case (iii) In this case, the direction of force acting on the block is opposite to the direction of displacement. Therefore, work done by force on the block will be NEGATIVE. |
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| 475. |
Arrange capillary tubes of different diameter on a piece of thermocol. Dip the capillary tubes in water. Compare the capillary rises in the tubes. Which has greater capillary rise? . |
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| 476. |
Arrange capillary tubes of different diameter on a piece of thermocol. Dip the capillary tubes in water. Compare the capillary rises in the tubes. Which has lower capillary rise? . |
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| 477. |
Arrange capillary tubes of different diameter on a piece of thermocol. Dip the capillary tubes in water. Compare the capillary rises in the tubes. How is the diameter of the tube and capillary rise related? . |
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| 478. |
A toy car initially moving with uniform velocity of 18 "km h"^(-1) comes to a stop in 2 s. Find the retardation of the car in S.I. units. |
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| 479. |
In a college hostal , a clever warden in order to know what thestudents are doing in theroom in his absence during night he switched off thelight in thecorridor and watchedtheroom through a glass partitionfrom the corridor. Explain why the objects in the room are more clearly visible when he switchedoff thecorridor lights than whenthere is light in the corridor. |
| Answer» Solution :Light from thecorridor is reflected by theglass pane separating it from the dark room. This reflected light enters our EYE along with thelight from inside thedark room. Since reflected light is more than the lightfrom the room andalso more intense, we cannot see THETHINGS inside the room. When the LIGHTS in the CORRIDOR are switched off, the light from the room now enters our eyes and the visibility improves. | |
| 480. |
The time rate of doing work is called power. 1 megawatt (MW) power means 10^(6) watt (W) power. |
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| 481. |
If two bodies od masses 1kg and 4kg are released from the heights where gravitational force on them is equal, then find the height of the heavier body if the lighter body is dropped from a height of 1 km. Take radius of earth as 6400 km. |
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Answer» Solution :(i) (1.) Find the height from where the lighter body of MASS 1kg is dropped from the given DATA. Find the GRAVITATIONAL force of attraction on the lighter body when it is at given height (1 km), using the formula, `F = (GMm)/((R + H)^(2))` (2.) If a body of mass 4 kg is to experience the same gravitational force of attraction as that of a body of 1 kg mass, find the required conditions. Here, the force F is proportional to mass and inversely proportional to the `(R + h)^(2)`. When mass is increased from 1 kg to 4 kg, then will the distance also increase? Now, TAKE the height of 4 kg mass as 'x'. Then,`""(GMm)/((R + h)^(2)) = (GM(4m))/((R + x)^(2))` Find the value of 'x' by appropriate substitutions in equation (2). (ii) 6402 km |
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| 482. |
The current flowing through a lamp is 0.2A. If the lamp is switched on for hour, what is the total electric that passes through the lamp? |
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Answer» SOLUTION :`I=q"/"t , Ixxt` `1HR =1xx60xx60s=3600s` `q=Ixxt=0.2Axx3600s=720C`. |
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| 483. |
Complete the following sentence : Wave velocity = …………….. xx wavelength. |
| Answer» SOLUTION :FREQUENCY | |
| 484. |
The pitch of a screw gauge is 1 mm and there are 100 divisions on the circular head. While measuring the diameter of a wire, the main scale reads 3 mm and the 55th division is in line with the base line. Find the diameter of the wire. Assume that the screw gauge is free from zero error. |
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Answer» Solution :Given, pitch = 1 mm, NUMBER of divisions on circular head = 100, main scale reading = 3 mm, number of division of circular head in line with base line is 55, so, p = 55. LEAST count `=("Pitch")/("Number of divisions on circular head")` `= (1 mm)/(100) = 0.01 mm` Circular scale reading `= p XX L.C. = 55 xx 0.01 ` mm Diameter of the WIRE = main scale reading + circular scale reading `= 3 mm + (55 xx 0.01 mm) ` `= 3 mm + 0.55 mm` =3.55 mm or 0.355 cm |
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| 485. |
__________are used in customsdepartment to detect smuggled goods. |
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| 486. |
Why did the actual speed differ from average speed? |
| Answer» SOLUTION :ACTUAL speed gives instantaneous speed of a BODY at any instant but AVERAGE speed is the total distance covered by total time TAKEN. | |
| 487. |
In petrol bunks, in what unit is tyre pressure measured? |
| Answer» SOLUTION :The tyre PRESSURE is MEASURED in UNITS of psi, it stands for pascal per INCH. | |
| 489. |
How can two whales in the sea, hundreds of kilometers apart, communicate? |
| Answer» SOLUTION :SOUND travels about 5 TIMES faster in water than in air. Therefore, two whales in the sea, hundreds of kilometers apart can communicate easily. | |
| 490. |
In each of the following a force F is acting on an object of mass m. The direction of dispalcement is from west to east shown by the longer arrow. Observer the diagrams carefully and state whether the work done by the force is negative, positive or zero. |
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Answer» Solution :(i) In case (a), the FORCE F is perpendicular to the displacement. So, the work done is zero. (ii) In case (b), the force F is in the same direction as that of the displacement. So, the work done is POSITIVE. (III) In case (c ), the force F is OPPOSITE to the direction of displacement. So, the work done is negative. |
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| 491. |
A body when projected up with an initial velocity u goes to a maximum height h in time t and then comes back at the point of projection. The correct statement is : |
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Answer» the average velocity is 2h/t |
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| 492. |
(a) State and explain the law of conservation of energy with an example. (b) Explain how, the total energy a swinging pendulum at any instant of time remains conserved. Illustrate your answer with the help of a labelled diagram. |
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| 494. |
Usinga screwgaugewithoutany zeroerrorthediameter of a wiredetermineas 2.74 mm . Ifthe screw advances 5 mmwhen thethimble isgiven10 completerotationswhat arethepossiblevaluses of thepitchscalereadingcircularscale readingand the leastcountif N isthenumberof headscaledivisions? |
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Answer» SOLUTION : AVERAGE of leftturningpoints`=(5+6+6)/(3) =(17)/(3)` `=5.6 ~~ 5.7` Average of rightturningpoints`= (18+18)/(2)=18` |
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| 495. |
Complete the following sentence : Infrasonic sound is of frequency ……………. |
| Answer» SOLUTION :below 20 HZ | |
| 496. |
Giving reasons and state the reading on a spring balance when it is attached to a floating block of wood which weighs 50 g in air. |
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| 497. |
The left arm of a manometer is connected to a container containing gas 'X' and the mercury level in the right arm is raised by 2 cm. Now without disconnecting the container of X, the right arm of the manometer is connected to another container containing gas 'Y' and the mercury level in the right arm is pushed down by 5 cm. Find the pressure exerted by the gases 'X' and 'Y'. |
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Answer» Solution :When the left ARM of the manometer is connected to the container of gas X, MERCURY in the right arm is RAISED by 2 cm. `:.` the mercury in the left arm is pushed down by 2 cm and the fifference in the mercury level in both the arms = 4cm `:.` the pressure of gas X=atmospheric pressure + pressure due to 4 cm of mercury column = 80 cm of Hg. When the right arm is connected to the container of gas Y, mercury in the right arm is pushed down by 5 cm `:.` The difference in the levels of mercury column in both the arms = 6 cm. Thus, pressure of Y = pressure of X+pressure due to 6 cm of mercury = 80 cm of Hg+6 cm of Hg = 86 cm of Hg |
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| 498. |
Take a metre scale and a long rope. Walk from one corner A of a basketball court to its opposite corner Calong its sides AB and AC. Measure the distance covered by you and magnitude of the displacement. What difference would you notice between the two in this case ? |
Answer» Solution : `to` The DISTANCE covered = A to B and B to C = AB + BC Displacement = A to C = AC Here, AC `lt` AB + BC Hence, the displacement is less than the distance covered. |
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| 499. |
How is the direction of flow of current between two charged conductors determined by their potentials ? |
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| 500. |
The slope of graph y-t give the magnitude of .......... (displacement, speed, acceleration) |
| Answer» SOLUTION :ACCELERATION | |