40048 + Interview Questions in Physics in Class 11

1.	Moment of inertia of a uniform solid sphere about an axis passing through the center along its diameter is
Answer» `(2)/(3)MR^(2)` `(5)/(3)MR^(2)` `(7)/(5)MR^(2)` `(2)/(5)MR^(2)` Answer :D

Discussion

2.	Match list I with II fro a projectile.
Answer» a-f, B-n, c-g, d-e a-h, b-f, c-e, d-g a-e, b-g, c-f, d-n a-e, b-g, c-h, d-f Answer :B

Discussion

3.	A liquid of density rho comes out with a velocity v from a horizontal tube of a real of cross section A. The reaction force exerted by the liquid on the tube is F a. Fprop v b. F prop v^(2) c. Fprop A d. F prop rho
Answer» a and B are correct b,C and d are correct a,c and d are correct All are correct Answer :B

Discussion

4.	A gaseous mixture enclosed in a vessel of volume V consists of one gram mole if a gas ‘A’ with gamma = (C_p/C_v) = 5/3and another gas .B. withgamma = 7/5at a certainof gases A and B are 4 and 32 respectively. The gases do not react with each other and are assumed to be ideal. The gaseous mixture follows the relation PV^(19//13)= constant in an adiabatic process [5^(19//13) = 10.5]The mixture is compressed adiabatically to 1/5 of its volume. Find the change in its adiabaticcompressibility in terms of V and T
Answer» `0.0248 V/T` `0.426 V/T` `0.0426V/T` `0.684V/T` ANSWER :A

Discussion

5.	A gaseous mixture enclosed in a vessel of volume V consists of one gram mole if a gas ‘A’ with gamma = (C_p/C_v) = 5/3and another gas .B. withgamma = 7/5at a certainof gases A and B are 4 and 32 respectively. The gases do not react with each other and are assumed to be ideal. The gaseous mixture follows the relation PV^(19//13)= constant in an adiabatic process [5^(19//13) = 10.5]Find the number of moles of gas B in the gaseous mixture
Answer» 4 MOLES 3 moles 2 moles 1 MOLE Answer :C

Discussion

6.	A gaseous mixture enclosed in a vessel of volume V consists of one gram mole if a gas ‘A’ with gamma = (C_p/C_v) = 5/3and another gas .B. withgamma = 7/5at a certainof gases A and B are 4 and 32 respectively. The gases do not react with each other and are assumed to be ideal. The gaseous mixture follows the relation PV^(19//13)= constant in an adiabatic process [5^(19//13) = 10.5]If T is raised by 1k from 300 k. Find the percentage change in volume.
Answer» 0.003 0.006 0.007 0.008 Answer :C

Discussion

7.	The velocity of a body moving in a vertical circle of radius r is sqrt(7gr) at the lowest point of the circle. What is the ratio of maximum and minimum tension ?
Answer» `4:1` `sqrt(7):1` `3:1` ` 2:1` Solution :TENSION is maximum at the lowest point and minimum at the highest point. Tension at the lowest point, `T_L = mg + (mv_L^2)/(r) = mg + (7 mgr)/(r) = 8 mg "" ( :. v_L = sqrt(7 GR))` Tension at the highest point, `T_H = (mv_H^2)/(r) - mg = (m(v_L^2 - 4 gr))/(r) - mg ( :. v_L^2 - v_H^2 = 4 gr)` `= (m(7 gr - 4 gr))/(r ) - mg = 3mg - mg = 2mg `. `:. (T_L)/(T_H) = 4/1 " or " (T_("max"))/(T_("min")) = 4/1` .

Discussion

8.	Inertia means
Answer» inability RESISTANCE to CHANGE its STATE MOVEMENT INERTIAL frame Solution :resistance to change its state

Discussion

9.	For a given gas molecule at a fixed temperature , the area under the Maxwell - Boltzmann distribution curve is equal to :
Answer» <P>`(PV)/(KT)` `(kT)/(PV)` `(P)/(NKT)` `PV` SOLUTION :`(PV)/(kT)`

Discussion

10.	A boat having length 3 m and breadth 2 m is floating on a lake. It sinks by 1 cm when a man gets on it. The mass of the man is ……………. .
Answer» 60 kg 55kg 65 kg 70 kg Solution :Weight of man = weight of ADDITIONAL water displaced `MG = 3 XX 2 xx 0.01 xx 10^3 xx G , m = 60 kg`

Discussion

11.	A highly elastic ball is released from rest at a distance h above the ground and bounces up and down. With each bounce a fraction f = 1/10 of its KE just before the bounce is lost. The time for which the ball will continue to bounce is nearly (Take g = 10 m//s^(2), h = 5m)
Answer» 1 sec 38 sec 84.3 sec 1.86 sec Answer :B

Discussion

12.	The temperature of an ideal gas is increased from 120 K to 480K. If at 120 K the root mean square velocity of the gas molecules is v , at 480 K it becomes
Answer» 4 v 2 v v/2 v/4 Answer :B

Discussion

13.	The radius of gyration of a body about an axis at a distance of 4 cm from its centre of mass is 5 cm. The radius of gyration about a parallel axis through centre of mass is
Answer» 2 cm 5 cm 4 cm 3 cm Answer :D

Discussion

14.	A gridstone has a constant acceleration of 4 rad s^(-1). Starting from rest, calculate the angular speed of the grindstone 2.5 s later.
Answer» ANSWER :`10 RAD s^(-1)`

Discussion

15.	Choose the correct options
Answer» iscosity of liquids increases with temperature viscosity of gases increases with temperature surface TENSION of liquids decreases with temperature for angle of contact `theta=0^(0)` liquid neither RISES nor falls on capillary Answer :B::C::D

Discussion

16.	A metal sphere of radius r and specific heat S is rotated about an axis passing through its centre at a speed of n rotations per second. It is stopped and 50% of its energy is used in increasing its temperature, then the raise in temperature of the shere is
Answer» `2/(5)(pi^(2)N^(2)r^2)/S` `1/(10)(pi^2n^2)/(r^2S)` `(7)/(8)pir^(2)n^(2)S` `(5(pim))/(14S)` ANSWER :A

Discussion

17.	Assertion: In the sytem shown in figure spring is first stretched then left to oscillate. At some instant kinetic energy of mass m is K. At the same instant kinetic energy of mass 2m should be K/2. Reason: Their linear momenta are equal and opposite and K=(p^2)/(2m) or K=1/m.
Answer» (a) If both Assertion and Reason are TRUE and the Reason is correct EXPLANATION of the Assertion. (B) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion. (c) If Assertion is true, but the Reason is false. (d) If Assertion is false but the Reason is true. Answer :A

Discussion

18.	The coefficient of apparent expansion of a liquid when determined using two different vessels A and B are gamma_1 and gamma_2 respectively. If the coefficient of linear expanison of vessel A is alpha find the coefficient of linear expansion of vessel B.
Answer» Solution :We KNOW that COEFFICIENT of real expansion FO liquid `(gamma_r)` = coefficient of apparent expansion of the liquid `(gamma_a)` + coefficient of volume or CUBICAL expansion of the vessel `(gamma_v),` i.e.,`gamma_r = gamma_a + gamma_v = gamma_a + 3 ALPHA` Since the liquid is same in both the vessel, so value of `gamma_r` is same. From vessel A, `gamma_r = gamma_1 + 3 alpha_1= gamma_1 + 3 alpha ( :. alpha_1 = alpha, given)` For vessel B. `gamma_r = gamma_2 + 3 alpha_2 :. gamma_1 + 3 alpha = gamma_2 + 3 alpha_2` or `alpha_2 = (gamma_1 + gamma_2)/(3) + alpha`

Discussion

19.	The motion of a particle of mass m is described byy = ut + 1/2 "gt"^2 . Find the force acting on the particle.
Answer» SOLUTION :We knowthat Bytakingderivative w.r.ttime on thebothside `:., v=u + GT` Takingderivativeon bothside Nowforcef= ma `:. F = MG` Equationrepresentaccelerationmotionundercomponentof DISPLACEMENT

Discussion

20.	Between two lubricating oils A and B, the coefficient of viscosity of A is greater than that of B. For a machine , which one of them is suitable in summer?
Answer» Solution :In SUMMER, the viscosity of a LIQUID DECREASES DUE to increases in temperature. A is more suitable because its coefficient of viscosity is greater.

Discussion

21.	Define surface tension of a liquid. Mention its S.I. unit and dimension.
Answer» Solution :The surface of a liquid is defined as the,force PER unit length of a liquid (or) the ENERGY per unit AREA of the surface of a liquid. `T = F/l` SI unit and dimensions of T are `Nm^(-1) and MT^(-2)`

Discussion

22.	A large spool of rope stands on the ground with the end of the rope lying on the top edge of the spool. A person grabs the end of the rope and walks a distance, holding onto it figure. The spool rolls behind the person without slipping. What is the length of rope that unwinds from the spool? How far does the spool's CM move?
Answer» Length of rope that unwinds from the SPOOL is `l` Length of rope that unwinds from the spool `l/2` Spool's CM MOVES through `l/2` Spools's CM moves through `l` Answer :B::C

Discussion

23.	Two bodies having the same mass 5kg each have different surface areas20m^2 and 10m^(2) in contact with a horizontal plane. If the coefficient of friction is 0.4, the forces of friction that come into play when they are in motion will be in the ratio
Answer» `1:1` `1:2` `2:1` `1:4` ANSWER :B

Discussion

24.	A Carnot engine operating between temperatures T_1 and T_2 has efficiency 1/6 When T_2 is lowered by 62K, its efficiency increases to 1/3 Then T_1 and T_2 are respectively
Answer» 372 K and 310 K 372 K and 330 K 330 K and 268 K 310 K and 248 K Answer :A

Discussion

25.	Suppose you design your system of dimensions and take velocity (V). Planck constant (h) and gravitational constant (G) as the fundamental quantities . What will be the dimensions of length (L), mass (M) and time (T) in this system ?
Answer» Solution :We know , `[V]=[LT^(-1)]`….(1)`[h]=[ML^(2)T^(-1)]`…(2) ` [G]=[M^(-1)L^(3)T^(-2)]`….(3) Now, we have thes three three simultaneous equations and three unknown i.e., M,L and T. We just have to solve these three equations to find out the values of M,L and T in terms of V,h and G. Let us reduce these three equations in two equations and two unknowns. `(2)xx(3) "gives" hg=L^(5)T(-3)`....(4) Now we have (1) and (4) in L and T only . cubing equation (1) and dividing in by (4) will eliminate T. `(V^(3))/(hG)=(L^(3)T^(-3))/(L^(5)T^(-3))=L^(-2)"":. L^(-2)(hG)/(V^(3))` or `L=h^(1//2)G^(1//2)V^(-3//2)` Put (A) in (1) to get `V=h^(1//2)G^(1//2)V^(-3//2)T^(-1)` `:.T=h^(1//2)G^(1//2)V^(-5//2)` put (A) and (B) in (2) to get, `h=M.(h^(1//2)G^(1//2)V^(-3//2))^(2) (h^(1//2)G^(1//2)V^(-5//2))^(-1) rArr h=M.h^(1)G^(1)V^(-3) h^(-1//2)G^(-1//2)V^(-5//2)=M h^(1//2)G^(1//2)V^(-1//2)` :. `M=h^(1/2) G^(1/2) V^(1/2)` ...(C)

Discussion

26.	The relation between U,P and V for an ideal gas is U=2+3PV . What is the atomicity of gas.
Answer» Solution :For an ADIABATIC process `dQ=0=dU+dW or 0=dU+PDV" _____"(1)` From the given equation `dU=3(PdV+VdP)` `:. 0=3(PdV+VdP)+PdV ("from "(1)) or 4P (dV)+3V(dP)=0 or 4[(dV)/V]=-3[(dP)/P]` On integrating, we get In `(V^(4))+ In (P^(3))="constant "(or) PV^(4//3)=constant` i.e., `gamma=4/3` i.e., GAS is polyatomic.

Discussion

27.	Two identical balls .A. and .B. are moving with same velocity. If velocity of .A. is reduced to half and of .B. to zero, then the rise in temperatures of .A. to that of .B. is
Answer» `3:4` `4:1` `2:1` `1:1` ANSWER :A

Discussion

28.	The pitch of a screw gauge is 0.5m and there are 50 divisins on its circular scale and one man scale division =0.5mm. Before starting the measurement, it is found that when jaws of the screw gauge are brought in contact, the zero of the circular scale lies 5 divisions above the reference line. When a metallic wire is placed betwen the jaws, four main scale divisions are clearly visible and 16^(th) division on the circular scale coincides with the reference line. The diameter of the wire is
Answer» `2.21mm` `2.11mm` `2.18mm` `2.23mm` ANSWER :A

Discussion

29.	Discuss the possibilities of work done to be zero.
Answer» Solution :Work done is zero in the following cases. (i) When the force is zero (F = 0). For example, a body MOVING on a horizontal smooth frictionless SURFACE will continue to do so as no force (not even friction) is acting along the plane. (This is an ideal situation.) (ii) When the displacement is zero (DR = 0). For example, when force is applied on a rigid wall it does not PRODUCE any displacement. Hence, the work done is zero as shown in figure. (iii) When the force and displacement are perpendicular `(theta = 90^(@))` to each other. When a body moves on a horizontal direction, the gravitational force (mg) does not work on the body, since it acts at right angles to the displacement as shown in Figure (b). In circular motion the CENTRIPETAL force does not do work on the object moving on a circle as it is always perpendicular to the displacement as shown in Figure (c)

Discussion

30.	A bodytied at end of a string of length .l. is rotated in a vertical circle. The velocity of the body at the highest point is sqrt(2gl). The maximum velocity of the bodywould be
Answer» `SQRT(6gl)` `sqrt(5gl)` `sqrt(7gl)` `sqrt(8gl)` ANSWER :A

Discussion

31.	A mass of 2kg attached to a spring of force constant 800N//m makes 100 oscillation. The time taken is (in seconds)
Answer» 31.4 62.8 125.6 16 Answer :A

Discussion

32.	From a complete ring of mass M and radius R, a sector angle is removed. What is the moment of inertia of the incomplete ring about axis passing through the center of the ring and perpendicular to the plane of the ring?
Answer» Solution :Let R be the radius of the ring and M be the total mass of the COMPLETE ring. Let m be the mass of the section removed from the ring thens, mass of the incomplete ring is M-m, Let us INTRODUCE a positive INTEGER (n), such that or `n=(360^(@))/( theta)` mass of incomplete ring =M=m `m=(M)/(3620^(@))xx theta` `:.` Mass of in completer ring `=M-(M)/(3602^(@))xx theta` Mass of incomplete ring `=M-(M)/(n)=M((n-1))/(n)` For example, (a) when `theta=60^(@), n=(360^(@))/(60^(@))=6` `:. n=1=5` Mass of incomplete ring `=(5)/(6)M` (b) When `0-30^(@), n=(360^(@))/(30^(@))=12` `n=1=11` Mass of incomplete ring `-(11)/(12)M` The moment of inertia of the incomplete ring is, `1-M((n-1)/(n))r^(2)`

Discussion

33.	A piece of aluminium falls from a height of 200m on a fixed non conducting slab which brings it to rest. If the specific heat of aluminium is 210 Cal/kg. the increase in temperature of the slab immediately after collision (assume that there is no loss of heat)
Answer» `2.2^(@)C` `3.3^(@)C` `4.4^(@)C` `5.5^(@)C` ANSWER :A

Discussion

34.	In figure shown below, the time taken by the projectile to reach from A to B is t then, the distance AB is equal to
Answer» `(UT)/(SQRT(3))` `(sqrt(3)ut)/(2)` `sqrt(3)ut` 2ut Answer :A

Discussion

35.	The displacement y of a wave travelling in the x direction is given by y=(2 xx 10^(-3)) sin(300t - 2x + pi/4), where x and y are measured in metres and t in second. The speed of the wave is
Answer» `150 ms^(-1)` `300 ms^(-1)` `450 ms^(-1)` `600 ms^(-1)` Solution :`150 ms^(-1)` From the standard EQUATION of wave, `y = a sin (OMEGA t - k x + phi)` Here , `omega = 600` and `k = 2` So , SPEED of wave is ` v = (omega)/(k) = (600)/(2) , v = 150` m/s

Discussion

36.	The earth is assumed to be a sphere of radius R. A platform is arranged at a height R from the surface of the Earth. The escape velocity of a body from this platfrom is f v, where v is its escape velocity from the surface of the Earth. The value of f is
Answer» `(1)/(SQRT(2))` `(1)/(3)` `(1)/(2)` `sqrt(2)` ANSWER :A

Discussion

37.	The power radiated by a black body is P, and it radiates maximum energy around thee wavelength lambda_(0). If the temperature of the black body is now changed so that it radiates maximum energy around a wavelength 3lambda_(0)//4, the power radiated by it will increase by a factor of
Answer» `(256)/(81)` `(64)/(27)` `(16)/(9)` `(4)/(3)` ANSWER :A

Discussion

38.	Two perfecdy elastic balls of same mass m are movkng with velocities u_(1)and u_2. They collide elastically n times. The kinetic energy of the system finally is:
Answer» `1/2 m/n u_(1)^(2)` `1/2 m/n (u_(1)^(2) + u_(2)^(2))` `1/2 m(u_(1)^(2) + u_(2)^(2))` `1/2 MN(u_(1)^(2) + u_(2)^(2))` ANSWER :C

Discussion

39.	The earth is assumed to be a sphere of radius R. A platform is arranged at a height R from the surface of the earth. The escape velocity of a body from this platfrom is fv_(e ), where v_e is its escape velocity from the surface of the earth. The value of f is
Answer» `SQRT(2)` `(1)/(sqrt(2))` `(1)/(3)` `(1)/(2)` Answer :B

Discussion

40.	A glass capillary tube sealed at both ends is 100cm long. It lies horizontally with the middle 10 cm containing mercury. The two ends of the tube which are equal in length contain air at 27^(0) C at a pressure of 76 cm of Hg. Now the air column at one end of the tube is kept at 0^(0)C and the other end is maintained at 127^(0)C. Calculate the lellgth of the air column which is at 0^(0)C and its pressure. (Neglect the change in volume of Hg and glass).
Answer» Solution : 2L + 10 = 100, i.e., L = 45 cm........ (1) Now when end A is cooled while B is heated the Hg column will be displaced TOWARDS A until the pressures on two sides of it again becomes equal, i.e., Now applying gas equation to the AIR enclosed in side A, `(45 AP_(0))/(300)= ((45-x)AP_(1))/(273) , " i.e., " P_(1) = (273 xx 45 xx P_(0))/(300 (45 - x)) ` .... (3) while for air on side B, `(45 AP_(0))/(300 ) = ((45 + x) AP_(2))/(400)` , i.e., `P_(2) = (400 xx 45 xx P_(0))/(300 (45 + x)) ` ....... (4) Substituting the values of `P_(1) and P_(2)`from equation (3) and (4) in (2), we get `(273 xx 45 xx P_(0))/(300 xx (45 - x)) = (400 xx 45 xx P_(0))/(300 xx (45 + x))` Which on solving gives x = `(127 xx 45 ) // 673 ` = 8.49 cm So the length of air column which is at `0^(0)`C = 45 - 8.49 = 36.51 cm and from equation (3) with `P_(0)`= 76 cm of Hg (given), `p_(1) = (273 xx 45 xx 76)/(300 xx 36.51 )` = 85.25 cm of Hg

Discussion

41.	Sand drops from a stationary hopper at the rate of 5 kg s^(-1) onto a conveyor belt moving with a constant speed of 2 m//s^(-1). What is the force required to keep the belt moving and what is the power delivered by the motor moving the belt ?
Answer» <P> Solution :IMPULSE J = Ft = mv , Force : `F = (mv)/(t), upsilon = 2 ms^(-1), (m)/(t) = 5 kg s^(-1) RARR F = 5 xx 2` = 10 N Power `P = (W)/(t) = (Fs)/(t) = F upsilon = 10 xx 2 = 20` watt.

Discussion

42.	Can a body have zero velocity and still be accelerating ?
Answer» Solution :YES. When a body is THROWN vertically upwards it has zero VELOCITY at its highest point . Even then it has acceleration equal to the acceleration due to GRAVITY in vertical motion .

Discussion

43.	A pipe 20 cm long is closed at one end, which harmonic mode of the pipe is resonantly excited by a 430 Hz source?Will this same source can be in resonance with the pipe, if both ends are open? Speed of sound = 340ms^(-1).
Answer» Solution :The frequency of `n^(th)`MODE of vibtration of a pipe closed at ONE end is given by `v_(n)=((2n-1)V)/(4L)` river `v=340ms^(-1),L=20cm =0.2m,v^(n)=430Hz` `therefore 430=((2n-1)340)/40.2 Rightarrow n=1`. Therefore, first mode of vibration of the pipe is excited, for open pipe since n must be an INTEGER, the same source cannot be in resonance with the pipe with both ends open.

Discussion

44.	If the breaking force of a nylon rope of diameter 4cm is 1.6xx10^(5)N, find the breaking force of the same nylon rope of diameter 2 cm
Answer» ANSWER :`4XX10^(4)N`

Discussion

45.	The variation of length of two metal rods A and B with change in temperature are shown in fig. The coefficients of linear expansion alpha_(A) for the metalA and the temperature T will be (Given alpha_(a) = 9 xx 10^(-6) //°C )
Answer» `alpha_(A) =3xx 10^(-6) //°C, 500^(@) C` `alpha_(A) = 3 xx 10^(-6)//""^(@) C, 222.22^(@) C` `alpha_(A) = 27 xx 10^(-6) //""^(@) C` `alpha_(A) = 27 xx 10^(-6)//""^(@) C, 222.22^(@) C` ANSWER :D

Discussion

46.	The kinetic theory of gases gives the formula PV=1/3Nmv^(2) for the pressure P exerted by a gas enclosed in a volume V. The term Nm represents
Answer» the MASS of a MOLE of the gas the mass of the present in the volume V the averatge mass of ONE MOLECULE of the gas the total number of molecules present in volume V Answer :B

Discussion

47.	An oxygen molecule has a mass of 5.30xx10^(-26) kg and a moment of inertia of 1.94xx10^(-46)kgm^2 about an axis through its centre perpendicular to the lines joining the two atoms. Suppose the mean speed of such a molecule in a gas is 500ms^(-1) and that its kinetic energy of rotation is two thirds of its kinetic energy of translation Find the average angular velocity of the molecule.
Answer» Solution :Inertia of the SYSTEM of ATOMS, `I=(m/2)r^2+(m/2)t^2` `I=mr^2` `:.r=SQRT(I/m)=sqrt(1.94xx10^(-46)/(5.30xx10^(-26))=0.60xx10^(-10)m` given `1/2(mr^2)(omega^2)=1/3mv^2` i.e `1/2(mr^2)(omega^2)=1/3mv^2""omega^2=2/3(v^2)/(r^2)` i.e `omega=v/rsqrt(2/3)`i.e. `omega=(0.8165xx500)/(0.6xx10^(-10))=680.4xx10^(10)` i.e `omega=6.804xx10^(12)rads^(-1)`

Discussion

48.	(A) : If body or a system has neither translational nor rotational motion then it is in complete mechanical equilibrium.(R ) : A body or system is said to be in mechanical equilibrium when net force and net torque acting on the body are zero.
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 but (R ) is false Both (A) and (R ) are false ANSWER :A

Discussion

49.	Consider the following statements A and B. Identify the correct choice in the given answers A. In a one dimensional perfectly elastic collision between two moving bodies of equal masses the bodies merely exchange their velocities after collision. B. If a lighter body at rest suffers perfectly elastic collision with a very heavy body moving with a certain velocity, then after collision both travel with same velocity.
Answer» A and B are correct Both A and B are wrong A is correct, B is wrong A is wrong, B is correct Solution :For A: Using the LAWS of conservation of LINEAR momentum and energy, the velocities of two bodies after perfectly ELASTIC collision are given by `v_1=((m_1+m_2)u_1)/(m_1+m_2)+(2m_2u_2)/(m_1+m_2)`...(i) `v_2=(2m_1u_1)/(m_1+m_2)+((m_2+m_1)u_2)/(m_1+m_2)`...(ii) where `m_1` and `m_2` are the masses of two bodies and `u_1` and `u_2` are the velocities of two bodies before collision. If `m_1= m_2`,then From (i) and (ii), we get `v_1=u_2 and v_2=u_1` i.e., in perfectly elastic collision of two MOVING bodies ofequal masses, the bodies merely exchange their velocities after collision. Thus, statement A is correct. For B: In Eqs. (i) and (i), If `m_2lt ltm_1` and `u_2= 0`, then `v_1=u_1 and v_2 = 2u_1` Thus, statement B is wrong.

Discussion

50.	The centre of mass of a ring of uniform mass distribution lies ………….
Answer» at the CENTRE of RING, but OUTSIDE the MATERIAL outside the ring material centre of ring, but INSIDE the material at the centre of ring Answer :A

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Moment of inertia of a uniform solid sphere about an axis passing through the center along its diameter is

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A liquid of density rho comes out with a velocity v from a horizontal tube of a real of cross section A. The reaction force exerted by the liquid on the tube is F a. Fprop v b. F prop v^(2) c. Fprop A d. F prop rho

The velocity of a body moving in a vertical circle of radius r is sqrt(7gr) at the lowest point of the circle. What is the ratio of maximum and minimum tension ?

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For a given gas molecule at a fixed temperature , the area under the Maxwell - Boltzmann distribution curve is equal to :

A boat having length 3 m and breadth 2 m is floating on a lake. It sinks by 1 cm when a man gets on it. The mass of the man is ……………. .

A highly elastic ball is released from rest at a distance h above the ground and bounces up and down. With each bounce a fraction f = 1/10 of its KE just before the bounce is lost. The time for which the ball will continue to bounce is nearly (Take g = 10 m//s^(2), h = 5m)

The temperature of an ideal gas is increased from 120 K to 480K. If at 120 K the root mean square velocity of the gas molecules is v , at 480 K it becomes

The radius of gyration of a body about an axis at a distance of 4 cm from its centre of mass is 5 cm. The radius of gyration about a parallel axis through centre of mass is

A gridstone has a constant acceleration of 4 rad s^(-1). Starting from rest, calculate the angular speed of the grindstone 2.5 s later.

Choose the correct options

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Assertion: In the sytem shown in figure spring is first stretched then left to oscillate. At some instant kinetic energy of mass m is K. At the same instant kinetic energy of mass 2m should be K/2. Reason: Their linear momenta are equal and opposite and K=(p^2)/(2m) or K=1/m.

The coefficient of apparent expansion of a liquid when determined using two different vessels A and B are gamma_1 and gamma_2 respectively. If the coefficient of linear expanison of vessel A is alpha find the coefficient of linear expansion of vessel B.

The motion of a particle of mass m is described byy = ut + 1/2 "gt"^2 . Find the force acting on the particle.

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Two bodies having the same mass 5kg each have different surface areas20m^2 and 10m^(2) in contact with a horizontal plane. If the coefficient of friction is 0.4, the forces of friction that come into play when they are in motion will be in the ratio

A Carnot engine operating between temperatures T_1 and T_2 has efficiency 1/6 When T_2 is lowered by 62K, its efficiency increases to 1/3 Then T_1 and T_2 are respectively

Suppose you design your system of dimensions and take velocity (V). Planck constant (h) and gravitational constant (G) as the fundamental quantities . What will be the dimensions of length (L), mass (M) and time (T) in this system ?

The relation between U,P and V for an ideal gas is U=2+3PV . What is the atomicity of gas.

Two identical balls .A. and .B. are moving with same velocity. If velocity of .A. is reduced to half and of .B. to zero, then the rise in temperatures of .A. to that of .B. is

Discuss the possibilities of work done to be zero.

A bodytied at end of a string of length .l. is rotated in a vertical circle. The velocity of the body at the highest point is sqrt(2gl). The maximum velocity of the bodywould be

A mass of 2kg attached to a spring of force constant 800N//m makes 100 oscillation. The time taken is (in seconds)

From a complete ring of mass M and radius R, a sector angle is removed. What is the moment of inertia of the incomplete ring about axis passing through the center of the ring and perpendicular to the plane of the ring?

A piece of aluminium falls from a height of 200m on a fixed non conducting slab which brings it to rest. If the specific heat of aluminium is 210 Cal/kg. the increase in temperature of the slab immediately after collision (assume that there is no loss of heat)

In figure shown below, the time taken by the projectile to reach from A to B is t then, the distance AB is equal to

The displacement y of a wave travelling in the x direction is given by y=(2 xx 10^(-3)) sin(300t - 2x + pi/4), where x and y are measured in metres and t in second. The speed of the wave is

The earth is assumed to be a sphere of radius R. A platform is arranged at a height R from the surface of the Earth. The escape velocity of a body from this platfrom is f v, where v is its escape velocity from the surface of the Earth. The value of f is

The power radiated by a black body is P, and it radiates maximum energy around thee wavelength lambda_(0). If the temperature of the black body is now changed so that it radiates maximum energy around a wavelength 3lambda_(0)//4, the power radiated by it will increase by a factor of

Two perfecdy elastic balls of same mass m are movkng with velocities u_(1)and u_2. They collide elastically n times. The kinetic energy of the system finally is:

The earth is assumed to be a sphere of radius R. A platform is arranged at a height R from the surface of the earth. The escape velocity of a body from this platfrom is fv_(e ), where v_e is its escape velocity from the surface of the earth. The value of f is

Sand drops from a stationary hopper at the rate of 5 kg s^(-1) onto a conveyor belt moving with a constant speed of 2 m//s^(-1). What is the force required to keep the belt moving and what is the power delivered by the motor moving the belt ?

Can a body have zero velocity and still be accelerating ?

A pipe 20 cm long is closed at one end, which harmonic mode of the pipe is resonantly excited by a 430 Hz source?Will this same source can be in resonance with the pipe, if both ends are open? Speed of sound = 340ms^(-1).

If the breaking force of a nylon rope of diameter 4cm is 1.6xx10^(5)N, find the breaking force of the same nylon rope of diameter 2 cm

The variation of length of two metal rods A and B with change in temperature are shown in fig. The coefficients of linear expansion alpha_(A) for the metalA and the temperature T will be (Given alpha_(a) = 9 xx 10^(-6) //°C )

The kinetic theory of gases gives the formula PV=1/3Nmv^(2) for the pressure P exerted by a gas enclosed in a volume V. The term Nm represents

(A) : If body or a system has neither translational nor rotational motion then it is in complete mechanical equilibrium.(R ) : A body or system is said to be in mechanical equilibrium when net force and net torque acting on the body are zero.

The centre of mass of a ring of uniform mass distribution lies ………….