40048 + Interview Questions in Physics in Class 11

1.	If 13.6 gm/c.c and 13.52 g/c.e are the densities of a liquid at 10^(@)C and 50^(@)C, find the coefficient of real expansion of the liquid
Answer» Solution :Density of the liquid at `10^(@)C (d_(1)) = 13.6 GM //c.c.` Density of the li1quid at `50^(@)C (d _(2)) = 13.52 gm //c.c` From `gamma _(R) = (d _(1) -d _(2))/( d _(2) (t _(2) -t _(1))) = (13.6 - 12.52)/( 13.52 (50-10)) = (0.08)/( 13.52 XX 40) = 0.0001479 therefore 14.79 xx 10 ^(-5) (C ^(@)) ^(-1)`

Discussion

2.	A false statement is
Answer» Angle of contact `thetalt90^(@)`, if cohesive FORCE `lt` adhesive force `xxsqrt(2)` Angle of contact `thetagt90^(@)`, if cohesive force `GT` adhesive force `xxsqrt(2)` If the radius of capillary is reduced to half, the RISE of liquid column becomes TWO times If the radius of capillary is reduced to half, the rise of liquid column becomes four times Answer :D

Discussion

3.	The average acceleration in one time period in a simple harmonic motion is
Answer» `A OMEGA^(2)` `A omega^(2)//2` `A omega^(2)//SQRT(2)` zero Answer :D

Discussion

4.	A calorimeter of water equivalent 10xx10^(-3)kg is filled with 70xx10^(-3)kg of a substance at its melting point. The substance is found to solidify completely in 21 minutes. A similar calorimeter containing 80xx10^(-3)kg of water at the same temperature cools at the rate of 1.5^(@)C per minute, the room temperature being the same in both cases. What is the latent heat of fusioin of the substance? (Specific heat capacity of water =4200 Jkg^(-1) K^(-1))
Answer» ANSWER :`170xx10^(3)JKG^(-1)`

Discussion

5.	Two 3 kg masses have velocities vecv_(1) = 2hati + 3hatj m//sand vecv_2 = 4hati-6hatj m/s . Find a) velocity of centre of mass, b) the total momentum of the system, c) The velocity of centre of mass 5s after application of a constant force vecF = 24hati N d) position of centre of mass after S if it is at the origin at t = 0.
Answer» Solution :(a) `vecv_( c) =(m_(1)vecv_(1) + m_(2)vecv_(2))/(m_(1) + m_(2)), vecv_( c)=(3(2hati + 3hatj)+3(4hati - 6hatj))/6, therefore` Velocity of centre of mass `vecV_( c) = 3hati - 1.5 HATJ ms^(-1)` b) The momentum of the system = `Mv_( c)=6 kg(3hati - 1.5 hatj) ms^(-1) = 18hati - 9hatj KGMS^(-1)` c) To find the velocity of centre of mass after 5 s of application of the force `vecF = 24hatj N` we first find the acceleration of the centre of mass. It is given by: `veca_( c) = vecF/M =(24hati)/6 = 4hati ms^(-2)` The velocity of centre of mass before the force is applied is `vecv_( c)`and from the EQUATION: `vecv_(c) = vecv_( c) + veca_(c).t` `vecv_(c ) =(3hati - 1.5 hatj) + (4hati)5 =(3hati -1.5 hatj + 20 hatj), V_(c )^(1) =(23 hati - 1.5 hatj) ms^(-1)` d) From the equation of the position vector `vecr = vecr_(0) + vecv_(0)t + 1/2 at^(2)`, where `vecr_(0)=VEC0` (origin at t=0), `vecv_(0) = vecv_(c ), veca = veca_( c)` and t= 5s `vecr =(3hati - 1.5 hatj) + 5 + 1/2(4hati) 25 =(15hati - 7.5 hatj + 50hati), therefore vecr =(65 hati - 7.5 hatj)`m The coordinates of the centre of mass after 5 s of application of the force `vecF`are (65 m, - 7.5 m)

Discussion

6.	The possible range of masses is (of the order of)
Answer» `10^(-30) KG ` to `10^30 kg ` `10^(-30)kg` to `10^56 kg ` `10^(-10)kg` to `10^10 kg ` `10^(-30) kg ` to `10^10kg ` ANSWER :B

Discussion

7.	An ideal gas undergoes a process in which co-efficient of volume expansion of gas gamma, varies with absolute temperature by the relation gamma=(2)/(T). Let C is molar heat capacity in this process and C_(p).C_(V) are molar heat capacities at constant pressure and volume respectively. Then
Answer» `C=3C_(V)+2R` `C=2C_(V)+2R` `C=C_(V)+2R` `C=C_(V)-R` ANSWER :C

Discussion

8.	Select the correct pair from the following statements. Vectors can be added :
Answer» ALGEBRICALLY and vectorially algebrically and geometrically graphically and gemetrically graphically and algebrically ANSWER :C

Discussion

9.	The rate of steady volume flow of water through a capilary tube of length .l. and radius .r. under a pressure difference of P is V. This tube is connected with another tube of the same length but half the radius in series. Then find the rate of steady volume flow through them. (The pressure difference across teh combination is P)
Answer» SOLUTION :`V/(17)`

Discussion

10.	A particle of mass m is made to move with a uniform speed "v' along the perimeter of a polygon of n sides inscribed in a circle of radius "a".
Answer» The magnitude of the inpulse at each corner of the polygon is 2mv sin `(2pi//a)` The magnitude of the impulse at each corner of the polygon is 2mv sin `(2pi//a)` The magnitude of change in MOMENTUM after it crosses two diaognally OPPOSITE corners of the polygon is zero The magnitude of in momentum after it crosses any two DIAGONALLY opposite corners is 2 mV Answer :A::B

Discussion

11.	Which of the following works on Pascal's law?
Answer» barometer hydraulic lift venturimeter sprayer Answer :B

Discussion

12.	A bob of mass m attached to an inextensible string of length l is suspended from a vertical support. The bob rotates in a horizontal circle withan angular speed omega rad/s about the vertical support. About the point of suspension
Answer» ANGULAR momentum is conserved angular momentum changes in magnitude but not in direction angular momentum changes in direction but not in magnitude angular momentum changes both in direction and magnitude Solution :Magnitude of radius vector `vec(r )= \|vec(r )\|= l`constant. Magnitude of the momentum `vec(p)` of the bob = `\|vec(p)\|`= mv = m`omega l` = constant As angular momentum `vec(L) = vec(r ) xx vec(p)` and the angle between `vec(r ) and vec(p)` is ALWAYS `90^(@)`. `\|vec(L)\| = l cdot m omega l cdot sin 90^(@) = m l^(2) omega` = constant ALSO, `vec(r)` is l aways radially outwards and `vec(p)` is TANGENTIAL. So `vec(L)` is always DIRECTED along the axis of rotation. So its direction is also fixed.

Discussion

13.	Which of the following device is used to measure the rate of liquid through a pipe ?
Answer» Thermometer Barometer Manometer Venturimeter Answer :D

Discussion

14.	The rate of …………….of a body about a given axis is…………….to…………….applied on the body.
Answer» Solution :CHANGE of ANGULAR momentum , DIRECTLY proportional , the EXTERNAL TORQUE.

Discussion

15.	Butane gas burns in air according to the following reaction. 2C_(4)H_(10) +13O_(2) rarr 10 H_(2)O +8 CO_(2). Suppose the initial and final temperature are equal and high enough so that all reactants and products act as perfect gases. Two moles of butane ar mixed with 13 moles of oxygen and then completely reacted. Find the final pressure (if the volume remains unchanged and the pressure before reaction is P_(0))?
Answer» ANSWER :`(6P_(0))/(5)`

Discussion

16.	The average translational energy and the rms speed of molecules in a sample of oxygen gas at 300 K are 6.21 xx 10^(-21) J and 484 m/s respectively. The corresponding values at 600 Kare nearly (assuming ideal gas behaviour)
Answer» `12.42 XX 10^(-21)` J, 968 m/s `8.78 xx 10^(-21)` J, 684 m/s `6.21 xx 10^(-21)` J, 968 m/s `12.42 xx 10^(-21)` J, 684 m/s Answer :D

Discussion

17.	If the angle between force and displacement is acute then the work done is
Answer» positive negative zero maximum Answer :A

Discussion

18.	The amplitude of SHM is 5cm , period4sec and initial phase is pi//6. Its displacement at t=0 [initial displacement] is
Answer» `2.5sqrt(2)CM` 5 cm 2.5 cm `5sqrt(2)cm` ANSWER :C

Discussion

19.	If v_(a) , v_(b) and v_(m) are the speed of sound in air , hydrogen and a metal at the same temperature , then …………. .
Answer» `v_(B) GT v_(a) gt v_(m)` `v_(m) gt v_(b) gt v_(a)` `v_(b) gt v_(m) gt v_(a)` `v_(a) gt v_(b) gt v_(m)` SOLUTION :`v_(m) gt v_(b) gt v_(a)`

Discussion

20.	Two discs of moment of inertiaI_(1) and I_(2) about their respectively axes (normal) to the disc and passing through the centre) , and rotating with angular speed omega_(1) and omega_(2) are brought into contact face to face with their axes of rotation coincident . What is the loss in kinetic energy of the system in the process ?
Answer» `(I_(1) I_(2) (omega_(1) - omega_(2))^(2))/(2 (I_(1) + I_(2)))` `(I_(1) I_(2) (omega_(1) - omega_2)^(2))/((I_(1) + I_(2)))` `(I_(1) I_(2) (omega_(1) + omega_(2))^(2))/((I_(1) - I_(2)))` `(I_(1) I_(2) (omega_(1) + omega_(2))^(2))/(2 (I_(1) - I_(2)))` ANSWER :A

Discussion

21.	Two balls of masses m_(1)=100 g and m_(2)=300 g are suspended from point A by two equal inextensible threads, each of length l=32/35m. Ball of mass m_(1) is drawn aside and held at the same level as A but at a distance (sqrt(3)/2)l from A, as shown in Fig. When ball m_(1) is released, it collides elastically with the stationary ball of mass m_(2). The maximum rise of centre of mass of the ball of massm_(2) is
Answer» `0.20m` `0.50 m` `0.75 m` `1m` Solution :Ball of mass `m_(1)` falls freely TILL thread becomes taut. At that instant inclination `theta` of the thread with the vertical be given by `sintheta=(((sqrt(3))/2l))/l=(sqrt(3))/2` or `theta=60^(@)` Ball of mass `m_(1)` falls freely through height. Velocity of this ball at this instant is `v=sqrt(2gxxl/2)=sqrt(gl)` It can be resolved into two components. i. `v cos theta`, along the thread. But thread is inextensible, hence this component decreases to zero (due to tension developed in the thread). ii. `v sin theta`, perpendicular to the thread. Due to this component ball STARTS to move along a circle whose centre is at `A`. According to law of conservation of ENERGY, Kinetic energy of ball `m_(1)` just before collision `=` Its kinetic energy at `AC +` Further loss of its potential energy `1/2m_(1)u_(1)^(2)=1/2m_(1) (sqrt(gl)sintheta)^(2)+m_(1)g(l-lcostheta)` `u_(1)=4m//s` According to law of conservation of momentums `m_(1)v_(1)+m_(2)v_(2)=m_(1)u_(1)+m_(2)u_(2)` and coefficient of restitution `e=(v_(2)-v_(1))/(u_(2)-u_(1))=1` substituting `u_(1)=4 m//s, u_(2)=, m_(1)=0.1 kg` and `m_(2)=0.3kg, v_(2)=2m//s,` the height to which it rises is `h=v_(2)^(2)/(2g)=0.20m`

Discussion

22.	Two balls of masses m_(1)=100 g and m_(2)=300 g are suspended from point A by two equal inextensible threads, each of length l=32/35m. Ball of mass m_(1) is drawn aside and held at the same level as A but at a distance (sqrt(3)/2)l from A, as shown in Fig. When ball m_(1) is released, it collides elastically with the stationary ball of mass m_(2). Velocity u_(1) with which the hall of mass m_(1) collides with the other ball is
Answer» `1m//s` `2m//s` `3m//s` `4m//s` Solution :Ball of MASS `m_(1)` falls freely till thread BECOMES taut. At that instant inclination `theta` of the thread with the vertical be given by `sintheta=(((sqrt(3))/2l))/l=(sqrt(3))/2` or `theta=60^(@)` Ball of mass `m_(1)` falls freely through height. Velocity of this ball at this instant is `V=sqrt(2gxxl/2)=sqrt(gl)` It can be resolved into two components. i. `v cos theta`, along the thread. But thread is inextensible, hence this component decreases to zero (due to tension developed in the thread). ii. `v sin theta`, perpendicular to the thread. Due to this component ball starts to move along a circle whose centre is at `A`. According to law of conservation of energy, Kinetic energy of ball `m_(1)` just before collision `=` Its kinetic energy at `AC +` Further loss of its potential energy `1/2m_(1)u_(1)^(2)=1/2m_(1) (sqrt(gl)sintheta)^(2)+m_(1)G(l-lcostheta)` `u_(1)=4m//s` According to law of conservation of momentums `m_(1)v_(1)+m_(2)v_(2)=m_(1)u_(1)+m_(2)u_(2)` and coefficient of restitution `e=(v_(2)-v_(1))/(u_(2)-u_(1))=1` substituting `u_(1)=4 m//s, u_(2)=, m_(1)=0.1 kg` and `m_(2)=0.3kg, v_(2)=2m//s,` the height to which it rises is `h=v_(2)^(2)/(2g)=0.20m`

Discussion

23.	Number of significant digit in 0.0060 are …...
Answer» ANSWER :2

Discussion

24.	An aircraft is flying at a heightof 3400 m above the ground . Iftheangle subtended ataground observation point by the aircraft positions10.0 s apart is30^(@) , what is thespeed of the aircraft ?
Answer» ANSWER :`182 " m s"^(-1)`

Discussion

25.	A horizontally oriented copper rod of length / is rotating about a vertical axis passing through its middle. Calculate the rotation frequency at which the rod ruptures. Breaking or rupture strength of copper is sigma and density of copper is rho.
Answer» Answer :`omega=SQRT((5 sigma)/(rho l^(2)))(or)n=(1)/(2PI) sqrt((8 sigma)/(rho l^(2)))`

Discussion

26.	P-V diagram of a diatomic gas is a straightline passing through origin. What is the molar heat capacity of the gas in the process
Answer» Solution :P-V DIAGRAM of the gas is a straight line passing through origin. HENCE, `P prop V or PV^(-1)=` constant Molar heat capacity in the process `PV^(N)=` constant is `C=(R )/(gamma-1) +(R )/(1-n)` Here, `gamma=1.4` (for diatomic gas) & n = -1 `:.C =(R )/(1.4-1) +(R )/(1+1)or C = 3R`

Discussion

27.	(A) In optical fibre, the diameter of the core is kept small. ( R) Light ray going form denser to rarer mediun is incident at an angle more than the critical angle required for total internal reflection
Answer» Both A and R are TRUE and R is the correct EXPLANATION of A Both A and R are true and R is not the correct explanation of A A is true and R is false Both A and R is false Answer :A

Discussion

28.	The potential energy of a system increases, if work is done
Answer» by the SYSTEM against a CONSERVATIVE FORCE by the system against a non-conservative force upon the system by a CONSERVATION force upon the system by a non-conservation force Answer :A

Discussion

29.	There are two wires of same material. Their radii and lengths are both in the ratio 1:2. If the extensions produced are equal, what is the ratio of the loads?
Answer» `1:2` `2:1` `1:4` `4:1` ANSWER :A

Discussion

30.	A ball is thrown vertically downwards from a height of 20 m with an initial velocity v_(0) It collides with the ground , loses 50 percent ofits energyin collision and reboundsto the same height .the initial velocity v_(0) is : (Take g = 10 ms^(-2))
Answer» `10ms^(-1)` `14 ms^(-1)` `20ms^(-1)` `28ms^(-1)` Solution :Let ball rebounds with speed v so ` :. "In" v^(2) -v_(0)^(2) =2gh ,v_(0) = 0 ` ` :. V= sqrt(2gh) =sqrt(2xx10xx20) = 20 m//s ` ENERGY just after rebound `E =1/2 mv^(2) =1/2 m xx m xx (20)^(2)` ` = 1/2 m xx400` = 200 m Joule 50 % energy LOSES in COLLISION means just before collisionenergyis 400 m By using energy conservation `1/2 mv_(0)^(2) +mgh = 400 m ` ` :. v_(0)^(2) = 800 - 2gh` ` :. v_(0)^(2) = 800 - 400` ` :. v_(0)^(2) = 400 ` ` :. v_(0) = 20 ms^(-1)`

Discussion

31.	A specific gravity bottle is completely filled with mass m of a liquid at 0^(@)C. If it is heated to t^(@)C, then what mass of the liquid will be expelled? Coefficient of real expansion of the liquid =gamma and coefficient of linear expansion of the material of the bottle =alpha.
Answer» ANSWER :`((gamma-3alpha)MT)/(1+gammat)`

Discussion

32.	Calculate the speed of efflux of kerosene oil from an orifice of a tank in which pressure is 4 atmosphere. Density of kerosene oil = 0.72 kg /lite.
Answer» <P> Solution :` P= 1.03 xx 9.8 xx 4 = 40 . 376 Nm^(-2), rho = 0.72 xx 10 ^(3)kg m ^(-3), H = P//rhog = 0.057m, ` ` v = sqrt( 2gh )= 0. 335 ms ^(-1)`

Discussion

33.	The angular frequency of a spring block system is omega_(0). This system is suspended from the ceiling of an elevator moving downwards with a constant speed v_(0). The block is at rest relative to the elevator. Lift is suddenly stopped. Assuming the downward as a positive direction. Then
Answer» The AMPLITUDE of the block is `v_(0)/(omega_(0)` The EQUATION of MOTION for the block is `(v_(0)/omega_(0))sinomega_(0)t` Both are correct Both are wrong Answer :C

Discussion

34.	A 2 kg stone is swung in a vertical circle by attaching it at the end of a string of length 2m. If the string can with stand a tension 140.6 N, the maximum speed with which the stone can be rotated is
Answer» `22 MS^(-1)` `44 ms^(-1)` `33 ms^(-1)` `11 ms^(-1)` ANSWER :D

Discussion

35.	From a point on the ground at a distance 2m from the foot of a vertical wall, a ball is thrown at an angle of 45^(@)of which just clears the top, of the wall and afterward strikes the ground at a distance 4m on the otherside The height of the wall is
Answer» `2//3m` `3//4m` `1//2m` `4//3m` ANSWER :D

Discussion

36.	Estimate the total number of molecules inclusive of oxygen, nitrogen, water vapour and other constituents in a room of capacity 30m^(3) at a temperature of 30^(@)C and 1 atmosphere pressure.
Answer» SOLUTION :At Boltzmann.s CONSTANT, `k_(B)=R/N,R=k_(B)N` Now, `PV=nRT=nk_(B)NT` `THEREFORE` The number of molecules in the room, `nN=(PV)/(k_(B)T)=(1.013xx10^(5)xx25)/(300xx1.38xx10^(-23))` The number of molecules in the room `=6.117.xx10^(26)`

Discussion

37.	If a body is projected with speed less than escape velocity, then (a) the body can reach a certain height and may fall down following straight line path (b) the body can reach a certain height and may fall down following a parabolic path (c) the body may orbit the earth in a circular path (d) the body may orbit the earth in an elliptical path.
Answer» only a & B are true only b & C are true only a,b & d are true all a,b,c & d are true Answer :D

Discussion

38.	A solid sphere of radius R is made of a material of density rhoand specific heat c. The sphere is initially at 220 K and is later suspended inside a chamber whose walls are at 0K. What time is required for the temperature of the sphere to drop to 160 K?
Answer» Solution :The energy radiated by the sphere is given by Stefan.s law , ` (dQ)/(dt) = sigma AT^4 = sigma (4pi R^2) T^4` ` = 4pi sigma R^2 T^4`.....(i) Due to energy loss, the temperature of the sphere is reduced. Rate of energy loss due to rate of decrease of temperature is `(dQ)/(dt) = mc (dT)/(dt)` `m= V rho = 4/3 pi R^3 rho ` ` therefore (dQ)/(dt) =- 4/3 pi R^3rho c ( (dT)/(dt) )`..(ii) Comparing (i) and (ii) ` 4pi sigma R^2 T^4 = - 4/3 pi R^3 rho c ((dT)/(dt) )` `rArr 3 sigma T^4 = - rho RC ((dT)/(dT))` ` rArr (rho R c)/(T^4) dT= -3sigma dt` INTEGRATING both sides, we get `rho Rc int_(T_1)^(T_2) T^(-4) dT = - 3 sigma int_(0)^(t) dt` where `T_1` and `T_2`are initial and final temperature of the sphere, respectively, and t is the time taken for the sphere to drop its temperature from ` T_1 "to" T_2` ` rArr t = (rho Rc)/(9 sigma) [ (1)/(T_2^3) - (1)/(T_1^3) ]` ` =(rho Rc)/(9 (5.67 XX 10^(-8)) ) [ (1)/(160^3) - (1)/(220^3) ]` = 0.3`rhoRc`

Discussion

39.	A steel wire is stretched by 5 kg wt. If the radius of the wire is doubled its Young.s modulus
Answer» REMAINS unchanged Becomes double Becomes half Becomes `1//4` times Answer :1

Discussion

40.	The distance between the inner and outer wheels of a car is 1.75 m and its centre of gravity is 0-50 m above the ground. What is the maximum speed with which the car can negotiate a curve of radius of 40 m without overturning ?
Answer» Solution : Distance between the inner and outer wheels of CAR = 2s = 1 -75 m Height of the C.G of the car from the ground = `h=0.5 m` Maximum SPEED = `v_("MAX") = ?` RADIUS of the circular road = r= 40 m `v_("max") = sqrt((gsr)/h) = sqrt((9.8 xx 0.875 xx 40)/0.5)` = 26.2 m/s

Discussion

41.	The shells of carbs found around a particular coastal location in Japan seem mostly to resemble the lengendary face of a Samurai. Given below are two explanation of this observed fact. Which of these strikes you as a scintific explanation? (a) A tragic sea accident several centuries ago drowned a young Samurai. As a tribute to his bravery, nature through its inscrutable ways immortalized his face by imprinting it on the carb shells in that area. (b) After the sea tragedy, fishermen in that area, in a gesture of honour to their dead hero, let free any crab shell caught by them which accidentally had a shape resembling the face of a Samurai. Consequently, the particular propagated. This is an example of evolution by artificial selection.
Answer» SOLUTION :Explanation (B)is a SCIENTIFIC explanation of the OBSERVED fact.

Discussion

42.	(A) : To unscrew a rusted nut, we need a wrench with longer arm. (R) : Wrench with longer arm reduces the torque of the arm.
Answer» Both 'A' and 'R' are TRUE 'R' is the CORRECT EXPLANATION of 'A' Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A' A' is true and 'R' is FALSE A' is false and 'R' are true ANSWER :C

Discussion

43.	In a legend the hero kicked a baby pig so that he is projected with a speed greater than that of his cry. If the weight of the baby pig is assumed to be 5 kg and the time of contact 0.01 sec, the force with which the hero kicked him was:
Answer» `5xx10^(-2)N` `2XX10^(5)N` `1.65xx10^(5)N` `1.65xx10^(3)N` Answer :B

Discussion

44.	What is an echo ?
Answer» SOLUTION :An echo is a repetition of SOUND PRODUCED by the reflection of sound waves from a WALL, muntaion or other OBSTRUCTING surface.

Discussion

45.	A bullet of mass m strikes a block of mass M connected to a light spring of stiffness k, with a speed v_(0) and gets into it. Find the loss of K.E. of the bullet.
Answer» ANSWER :`("MMV"_(0)^(2))/(2(M+m)`

Discussion

46.	Degree of freedom of a polyatomic gas is :
Answer» `ge5` `ge4` `gt6` `ge6` SOLUTION :A polyatomic gas has three translational and three rotational degrees of freedom. Also, it has a NUMBER of vibrational MODES. So, ` f ge 6`

Discussion

47.	The SI unit of magneitc flux is
Answer» `Wb//m^2` `Am^2` Oersted Weber Answer :D

Discussion

48.	(I) Gravitational force is a central force. (II) Energy of the satellite is negative sometimes. Which one of Incorrect?
Answer» I only II only both are correct None Answer :B

Discussion

49.	A vertical U tube of uniform cross-section contains water up to a heightof 0.3m. Show that if water on one side is depressed and then released it motion up and down the two sides of the tube is SHM and calculate its time period.
Answer» Solution :Refer to are `T=2pisqrt((H)/(G))=2XX(22)/(7)sqrt((0.3)/(9.8))=1.089s`

Discussion

50.	A particleof mass 10 kg is kept on the surface of a uniform sphere of mass 100 kg and radius 10 cm. Find the work to be done against the gravitational force between them to take the particle far away from the sphere is (G = 6.67 xx 10^(-11) Nm^(2)kg^(-2))
Answer» `6.67 XX 10^(-10)J` `6.67 xx `10^(-9)J` `3.33 xx 10^(-10)J` `13.34 xx 10^(-10)`J Answer :A

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

If 13.6 gm/c.c and 13.52 g/c.e are the densities of a liquid at 10^(@)C and 50^(@)C, find the coefficient of real expansion of the liquid

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The possible range of masses is (of the order of)

An ideal gas undergoes a process in which co-efficient of volume expansion of gas gamma, varies with absolute temperature by the relation gamma=(2)/(T). Let C is molar heat capacity in this process and C_(p).C_(V) are molar heat capacities at constant pressure and volume respectively. Then

Select the correct pair from the following statements. Vectors can be added :

A particle of mass m is made to move with a uniform speed "v' along the perimeter of a polygon of n sides inscribed in a circle of radius "a".

Which of the following works on Pascal's law?

A bob of mass m attached to an inextensible string of length l is suspended from a vertical support. The bob rotates in a horizontal circle withan angular speed omega rad/s about the vertical support. About the point of suspension

Which of the following device is used to measure the rate of liquid through a pipe ?

The rate of …………….of a body about a given axis is…………….to…………….applied on the body.

The average translational energy and the rms speed of molecules in a sample of oxygen gas at 300 K are 6.21 xx 10^(-21) J and 484 m/s respectively. The corresponding values at 600 Kare nearly (assuming ideal gas behaviour)

If the angle between force and displacement is acute then the work done is

The amplitude of SHM is 5cm , period4sec and initial phase is pi//6. Its displacement at t=0 [initial displacement] is

If v_(a) , v_(b) and v_(m) are the speed of sound in air , hydrogen and a metal at the same temperature , then …………. .

Number of significant digit in 0.0060 are …...

An aircraft is flying at a heightof 3400 m above the ground . Iftheangle subtended ataground observation point by the aircraft positions10.0 s apart is30^(@) , what is thespeed of the aircraft ?

A horizontally oriented copper rod of length / is rotating about a vertical axis passing through its middle. Calculate the rotation frequency at which the rod ruptures. Breaking or rupture strength of copper is sigma and density of copper is rho.

P-V diagram of a diatomic gas is a straightline passing through origin. What is the molar heat capacity of the gas in the process

(A) In optical fibre, the diameter of the core is kept small. ( R) Light ray going form denser to rarer mediun is incident at an angle more than the critical angle required for total internal reflection

The potential energy of a system increases, if work is done

There are two wires of same material. Their radii and lengths are both in the ratio 1:2. If the extensions produced are equal, what is the ratio of the loads?

A ball is thrown vertically downwards from a height of 20 m with an initial velocity v_(0) It collides with the ground , loses 50 percent ofits energyin collision and reboundsto the same height .the initial velocity v_(0) is : (Take g = 10 ms^(-2))

A specific gravity bottle is completely filled with mass m of a liquid at 0^(@)C. If it is heated to t^(@)C, then what mass of the liquid will be expelled? Coefficient of real expansion of the liquid =gamma and coefficient of linear expansion of the material of the bottle =alpha.

Calculate the speed of efflux of kerosene oil from an orifice of a tank in which pressure is 4 atmosphere. Density of kerosene oil = 0.72 kg /lite.

The angular frequency of a spring block system is omega_(0). This system is suspended from the ceiling of an elevator moving downwards with a constant speed v_(0). The block is at rest relative to the elevator. Lift is suddenly stopped. Assuming the downward as a positive direction. Then

A 2 kg stone is swung in a vertical circle by attaching it at the end of a string of length 2m. If the string can with stand a tension 140.6 N, the maximum speed with which the stone can be rotated is

From a point on the ground at a distance 2m from the foot of a vertical wall, a ball is thrown at an angle of 45^(@)of which just clears the top, of the wall and afterward strikes the ground at a distance 4m on the otherside The height of the wall is

Estimate the total number of molecules inclusive of oxygen, nitrogen, water vapour and other constituents in a room of capacity 30m^(3) at a temperature of 30^(@)C and 1 atmosphere pressure.

A solid sphere of radius R is made of a material of density rhoand specific heat c. The sphere is initially at 220 K and is later suspended inside a chamber whose walls are at 0K. What time is required for the temperature of the sphere to drop to 160 K?

A steel wire is stretched by 5 kg wt. If the radius of the wire is doubled its Young.s modulus

The distance between the inner and outer wheels of a car is 1.75 m and its centre of gravity is 0-50 m above the ground. What is the maximum speed with which the car can negotiate a curve of radius of 40 m without overturning ?

(A) : To unscrew a rusted nut, we need a wrench with longer arm. (R) : Wrench with longer arm reduces the torque of the arm.

In a legend the hero kicked a baby pig so that he is projected with a speed greater than that of his cry. If the weight of the baby pig is assumed to be 5 kg and the time of contact 0.01 sec, the force with which the hero kicked him was:

What is an echo ?

A bullet of mass m strikes a block of mass M connected to a light spring of stiffness k, with a speed v_(0) and gets into it. Find the loss of K.E. of the bullet.

Degree of freedom of a polyatomic gas is :

The SI unit of magneitc flux is

(I) Gravitational force is a central force. (II) Energy of the satellite is negative sometimes. Which one of Incorrect?

A vertical U tube of uniform cross-section contains water up to a heightof 0.3m. Show that if water on one side is depressed and then released it motion up and down the two sides of the tube is SHM and calculate its time period.

A particleof mass 10 kg is kept on the surface of a uniform sphere of mass 100 kg and radius 10 cm. Find the work to be done against the gravitational force between them to take the particle far away from the sphere is (G = 6.67 xx 10^(-11) Nm^(2)kg^(-2))