InterviewSolution
Saved Bookmarks
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.
| 751. |
A small magnet is suspended by a silk thread from a rigid support such that the magnet can freely swing. How will it rest ? Draw a diagram to show it. |
| Answer» Solution :It will REST in the geographic north-south DIRECTION with north pole towards the geographic north, MAKING some ANGLE with the HORIZONTAL . | |
| 752. |
A stone is dropped from the top of a tower 750 m high into a pond of water at the base of the tower. When is the splash heard at the top ? (Given g=10 ms^(-2) and speed of sound =340 m s^(-1)). |
|
Answer» SOLUTION :Height = 750M `h=ut+0.5 g t^(2)` The INITIAL velocity is 0 `750=0.5 xx 10 xx t^(2)` `t=10sec` Speed of sound is 340m/sec So, time TAKEN to travel 750m upwards is, `750/340=2.20s` time taken `=10+2.20=12.2 sec`. |
|
| 753. |
How does the sound produced by a vibrating object in a medium reach your ear ? |
|
Answer» |
|
| 754. |
Correct the following. Force of attraction increases when an object is raised from earth's surface |
|
Answer» |
|
| 755. |
The work done on an object does not depend upon the : |
|
Answer» displacement |
|
| 757. |
When the handle of a screwjack is rotated 8 times, the load is raised by 10 cm. If the length of the handle is 0.5 m, the M.A is |
| Answer» Answer :D | |
| 758. |
What is the range of frequencies associated with (a) Infrasound (b) Ultrasound |
|
Answer» Infrasound has frerquencies less than 20 HZ (b) ULTRASOUND Ultrasound has frequencies more than 20,000 Hz. |
|
| 759. |
Energy enters in a food chain through: |
|
Answer» PRIMARY consumers |
|
| 760. |
Which of the following can sometimes be ‘zero’ for a moving body?i. Average velocityii. Distance travellediii. Average speediv. Displacement |
|
Answer» Only (i) |
|
| 761. |
Deep pond of water has its top layer frozen during winter. State the expected temperature of water layer (i) just in contact withice (ii) at the bottom of pond. |
|
Answer» |
|
| 762. |
A body initially at rest travels a distance 100 m in 5 s with a constant acceleration. Calculate : (i) the acceleration, and (ii) the final velocity at the end of 5 S. |
|
Answer» Solution :GIVEN, INITIAL velocity U=0, distance S = 100 m, time taken t = 5 s. (i) From equation of motion S = ut `+(1)/(2) at^(2)` `100 =0xx5+(1)/(2)xx a xx(5)^(2)` or `100 =(1)/(2) xx25 a` or Acceleration a = `(100xx2)/(25) = 8 m s^(-2)` (ii) From equation of motion v = u + at FINAL velocity v = 0 + 8 `xx5` = 40 m `s^(-1)` . |
|
| 763. |
Name the S.I. unit of heat. How is it related to the unit calorie? |
|
Answer» |
|
| 764. |
A wave pulse of frequency 200 Hz, on a string moves a distance 8 m in 0.05 s. Calculate the wavelength of wave on string. |
|
Answer» SOLUTION :Wave VELOCITY on string V = velocity of wave pulse on it = 160 `ms^(-1)` From relation V= `F lambda` , Wavelength of wave `lambda = V/f = (160)/(200) = 0.8 m` |
|
| 765. |
The rate of change of momentum of an object is proportioanl to |
|
Answer» MASS of the BODY |
|
| 766. |
Explain how the human ear works . |
Answer» Solution : Outer ear pinna collects the sound from the surroundings and passes into the auditory canal. LEADS to the ear drum or tympanic membrane the compressions and rarefactions reaches itand ear drum vibrates, amph bed several TIME by THREE bones (hammer anvil and stir rup) in the middle ear. PRESSURE vibrations are received the inner ear turned to electrical are SENT to the brain via the auditory nerve and brain interprets them as sound. |
|
| 767. |
A wooden crate with a heavy machine weighing3000 N slides on the ground when pushed by a lever AB of length100 cm as shownin the figure. The force required to slide the crate acts at a distance of 10 cm from the fulcrum . If the coefficient of friction betweenthe crate and the ground is sqrt(2), find the effort required to move the crate. (Take the value ofsqrt(2)=1.4) |
Answer» Solution :Different forces that act on thecrate are shown in the figure  Fromthe figure it is clear that R + L sin 45 = mg `R=[mg-(L)/(SQRT(2))]` and the force that is responsible forthe motionof the roller is L ` cos 45^(@)`. Thus, ` L cos 45^(@) = f = MU R rArr (L)/(sqrt(2))= mu (mg -(L)/(sqrt(2)))` `(L)/(sqrt(2))= mu mg.(mu L)/(sqrt(2)) rArr (L)/(sqrt(2))(mu + 1)=mu mg` Or ` L = (sqrt(2)mu mg)/(mu +1)` Now, (effort) (effort arm) = (load) (load arm) Effort `=(Lxxl)/(e)=(l)/(e) ((sqrt(2)mu mg)/(mu + 1))` GIVEN ` l=100 cm, e = 100 cm`, ` mg = 3000 N ` and `mu = sqt(2)` `=((10)/(100))((sqrt(2)xxsqrt(2)xx3000)/(sqrt(2)+1))=250 N` |
|
| 768. |
The part of human ear that convert sound vibrations into electrical Signal are |
|
Answer» Tympanic membrane |
|
| 769. |
A closed calorimeter of negligible water equivalent contains 1 kg of ice at 0^(@)C, the 1 kg of steam at 100^(@)C is pumped into it. Find the ratio of mass of steam to water remaining in the calorimeter after attaining equilibrium temperature. Take the efficiency of the calorimeter as 90%. Find the amount of heat lost to surroundings. |
| Answer» Solution :Consider the FOLLOWING points to solve the problem. Is a sphere one, TWO or three dimensional body ? Does the sphere have linear, areal or VOLUMETRIC expansion ? Does the mass of a body affected when it expands on HEATING? | |
| 770. |
If two plane mirrors are placed with the reflecting surfaces perpendicular to each other, which of thefollowing statementis true? |
|
Answer» The RAYS incident on thefirst mirror and THERAYS REFLECTED from the second mirror are always parallel. |
|
| 771. |
What name is given to the persistance of sound in a big hall or auditorium? |
|
Answer» |
|
| 772. |
If the density of ice is 0.9gcm^(-3), what portion of an iceberg will remain below the surface of water in a sea? (Density of sea water =1.1gcm^(-3)) |
|
Answer» |
|
| 773. |
Fill in the following blanks with suitable words: (a) Sound is caused by............ (b) A sound wave consists of places of higher pressure called.........and places of.........pressure called............ (c) Wave speed in metres per second equals frequency in........multiplied by........in......... (d) Sound cannot travel through......... (e) The speed of sound in a solid is........than the speed of sound in air. (f) When the frequency of the sound is increased, the wavelength......... |
|
Answer» |
|
| 774. |
A racing car has a uniform acceleration of 4 ms ^(-2). What distance will it cover in 10 s after the start ? |
|
Answer» Solution :Here, `u = 0,a = 4 ms ^(-2) , t = 10 s ` `s = ut + (1)/(2) at ^(2)` `0 = xx 10 + (1)/(2) xx 4 xx (10) ^(2)` `= 0 + 2 xx 100 = 200 m` The car will cover a DISTANCE of 200 m. |
|
| 775. |
What is the acceleration of free fall? |
| Answer» SOLUTION :Acceleration of free fall is the acceleration produced when a along. It is denoted by g and its value on the surface of the EARTH is `9.8m^(2)`. | |
| 776. |
Complete the following sentences: A piece of wood is held under water. The upthrust on it will be ………..the weight of the wood piece. |
|
Answer» |
|
| 777. |
The zero-error in the spring balance shown and the correct weight of the solid, suspended from it, are equal, respectively, to: |
|
Answer» `+2g` WT, 19 g wt |
|
| 779. |
What conclusions can be drawn from J.J. Thomson's experiment on discharge phenomenon ? |
| Answer» | |
| 780. |
Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen, why ? |
| Answer» SOLUTION :It is due to the very high speed of light that the flash of lightning is SEEN first and it is due to COMPARATIVELY low speed of sound that the thunder is heared a few seconds LATER ( THORUGH they are produced at the same time). | |
| 781. |
What is meant by the terms mass and weight? |
|
Answer» • The force of ATTRACTION exerted by EARTH on a body is REFERRED as weight. |
|
| 782. |
How many neutral points can be obtained in a given plane perpendicular to the length of the two parallel wires conducting current in the same direction ? Explain, neglect earth's magnetic field of a bar magnet NS. |
| Answer» Solution :The wire B is repelled by both the wires A and C as they carry current in the opposite direction to that of B. however, as 'C' carries large current it repels 'B' with greater force than 'A'. Hence, 'B' MOVES towards A. | |
| 783. |
What are the advantagesof AC over DC? |
|
Answer» Solution :Advantages of AC over DC are, i) The VOLTAGE of an AC can be varied easily using a transformer. ii) The AC can be carried over long distances using step up transformers. iii) The loss of energy while DISTRIBUTING current in the form of AC is NEGLIGIBLE. iv) DC cannot be transmitted as such, but AC can be easily converted to DC. v) Generating AC is easier than DC, AC can produce electromagnetic INDUCTION which is useful in several ways. |
|
| 784. |
A rod of length (f/2) is placed along theaxis of a concave mirror of focal length f. If the near ead ofthe real image formed by the mirror just touches thefar end of the rod, find its magnification. |
|
Answer» Solution :(i) DRAW a ray diagram representing the given situation. Let AB be theobject and A be thenear END of the object and Bbe the far end of theobject. Let A'B' be the image formed. As B' COINCIDES with the end B at the centre of CURVATURE, `:. ` the distance of B from the mirror = 2f. Let the length of the object be `f/2`. The end A is at a distance of `(2f-f/2)`. By using`1/f = 1/v - 1/u`, Determine the distance of A'B', from the mirror and find the length of the image. u= 2f - d The magnification , `m = ("length of the image")/("length of the object") ` (ii) m = 2 |
|
| 785. |
Mass of a man is 60kg. He climbs up 20m height with a bucket having water of mass 15kg. So, work done is ………… kJ. (g=9.8ms^(-2)) |
|
Answer» 15 `=60kg+15kg=75kg` WORK = `MGH` `=(75)(9.8)(20)` `=14,700J` `~~15,000J` `=15xx10^(3)J=15kJ` Note : If g is taken as `g=10ms^(-2)`, then the answer would be EXACT `15,000J=15kJ`. |
|
| 786. |
You have a bag of cotton and an iron bar, each indicating a mass of 100 kg when measured on a weighing machine. In reality one is heavier than other. Can you say which one is heavier and why? |
| Answer» Solution :The cotton bag is heavier than the iron bar. The cotton bag EXPERIENCES lrger UPTHRUST of ar than the iron bar. So the MACHINE INDICATES sale meis for cotton bag than its actual mass. | |
| 787. |
Light travels from a rarer medium to a denser medium. The angle of incidence and refraction are respectively 45^@ and 30^@. Calculate the refractive index of the second medium with respect to the first medium. |
|
Answer» Solution :Angle of INCIDENCE `I = 45^@` : Angle of REFRACTION `r= 30^@` `""_(1) mu_(2)= (sin i)/(sin r) = (sin 45^@)/(sin 30^@) = (1 SQRT2)/(1 //2) = sqrt2 = 1.414` |
|
| 788. |
A stone falls down from the top of a wall in 1 s to the ground (g=10 m/s^2) What is the speed of the stone just before it touches the ground? |
|
Answer» `=0+10xx1` `=10m/s` |
|
| 789. |
If a boy is sitting on a merry-go-round, moves with constant speed of 10 m s^(-1) he would be … |
|
Answer» in STEADY state `therefore` He would be performing accelerated motion. |
|
| 790. |
How is work calculated, if a applying force to the object (i) there is no displacement (ii) displacement is perpendicular to the force. |
|
Answer» Solution :(i) If a PERSON tries to moves a loaded truck on a horizontal surfac, the truck does not move, i.e., the displacement is zero. Here, work done `W=Fxx0=0`. (ii) An OBJECT performing UNIFORM circular motion. Here, centripetal force acts towards the centre of the circle. The displacement acts tangentially. THEREFORE, the displacement is perpendicular to the force. Hence, the work done by the centripetal force on the object is zero. |
|
| 791. |
Assert ion (A) :0 . ^(@) C= 273 . 16 K . For our convenience we take is as 273 K after roundig off the decimal .Reason (R) : To convert a temperature on the Celsiusscale we have to add 273 to the give temperature. |
|
Answer» |
|
| 793. |
A balance similar to Roman steelyard is down in the figure. G is the position of centre of gravity in the figure . G is theposition of centre of gravity of the beam.Given OG=3 cm, OH =4 cm and OP =5 cm . If the weight of the rider is 60 gf, find the weight of the beam, least count of the balance and the maximum load that can be measured using the balance. |
|
Answer» Solution : (i) Principleof moments (ii) Working of Roman steel yard (iii) Weight of the beam acts at its position of CENTRE of GRAVITY. (iv) RIDER at zero mark on the SCALE balances the weight of the beam. (v) Distance of the rider from its zero mark on the scale is directlyproportional to the load attached. (VI) Weight of the beam = 100 gf Least count of the balance = 15 gf Maximum load that can be attached = 450 gf |
|
| 794. |
Describe Goldstein's experiment on canal rays. |
| Answer» | |
| 795. |
The figure shows a jar containing honey and kerosene Which liquid is the mobile liquid? |
|
Answer» |
|
| 796. |
Rulers, measuring tapes and metre scales are used to measure . . . . . |
|
Answer» Mass |
|
| 797. |
Have you ever experienced that the train in which you are sitting appears to move while it is at rest ? Discuss and share your experience. |
| Answer» SOLUTION :The train in which you are sitting is at rest at a STATION. If another train on the other track is MOVING, your train appears to move in OPPOSITE DIRECTION. | |
| 798. |
A body is volume 100cm^(3) weighs 5 kgf in air. It is completely immersed in a liquid of density 1.8xx10^(3)kgm^(-3). Find (i) the upthrust due to liquid and (ii) the weight of the body in liquid. |
|
Answer» |
|
| 799. |
A strong transverse horizontal pulse, created at one end of a string, is observed to complete 5 single journeys (from one end to other end) along its length, before fading out. The initial and final readings, on a stop clock used in the experiment, are as shown in (Fig. MT 2.6). If the length of the string is L metre, find the speed of the pulse through the string. . |
|
Answer» Solution :Time TAKEN by PULSE for 5 single JOURNEYS `= (5 + 45) s` =`50 s` Time taken by pulse for single journey `= 10 s` SPEED of the pulse `= (L//10) m//s`. |
|
| 800. |
What is the scientific name of the 'upward force acting on an object immersed in a liquid ? |
|
Answer» |
|