Explore topic-wise InterviewSolutions in .

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.

13651.

Find the power of an engine which can draw a train of77. 400 metric ton up the inclined plane of 1 in 98 at the rate of 10ms^(-1). The resistance due to friction acting on the train is 10 N per ton.

Answer»

350 kW
400 kW
440 kW
500 kW

Answer :C
Discussion
13652.

A 60kg box sledge is travelling horizontally on ice at a speed of 10 ms^(-1). A 90kg packet is dropped on it vertically. The subsequent velocity of the sledge is

Answer»

`1ms^(-1)`
`2MS^(_1)`
`3MS^(-1)`
`4ms^(-1)`

Answer :D
Discussion
13653.

A gas at 27^@ C temperature and 30 atmospheric pressure is allowed to expand to the atmospheric pressure. If the volume becomes 10 times its initial volume, the final temperature becomes .....

Answer»

`100^@C`
`173^@C`
`273^@C`
`-173^@C`

Solution :Here INITIAL temperature of gas
`(T_1)=27^@C` =300 K
Initial pressure `(P_1)`=30 atm
Initial volume `(V_2)`=10 V
Final pressure `(P_2)`=1 atm
Final volume `(V_2)`=10 V
According to general EQUATION of gas,
`(P_1V_1)/T_1=(P_2V_2)/T_2`
`therefore (30xxV)/300=(1xx10V)/T_2`
`therefore T_2`=100 K =`-173^@C`
Discussion
13654.

A person of mass m is on the floor of a lift. The lift is moving down with an acceleration 'a'. Then : (a) the net force is acting in downward direction and is equal to mg(b) the force mg must be greater than reaction force(c ) the man appears to be lighter than his true weight by a factor (a/g)

Answer»

a, B, C are CORRECT
b and c are correct
a and c are correct
only b is correct

ANSWER :B
Discussion
13655.

A sphere is moving on a smooth surface with linear speed v_(0) and angular velocity omega_(0). It finds a rough inclined surface and it starts climbing up:

Answer»

if `v_(0)gtRomega_(0)` FRICTION force will act downwards
if `v_(0)ltRomega_(0)`, frictio force will act upwards
if `v_(0)=Romega_(0)` no friction force will act
if all above case friction will act upwards

Answer :A
Discussion
13656.

In changing the state of a gas adiabatically from an equilibrium state A to another equilibrium state B, an amount of work equal to 22.3 J is done on the system. If the gas is taken from state A to B, via a process in which the net heat absorbed by the system is 9.35 cal, how much is the net work done by the system in the latter case ?

Answer»

SOLUTION :Net WORK done by the system `= 9. 35 XX 4. 19 - 22.3 = 16. 81 J`
Discussion
13657.

A particle of mass m is projected from the ground with an initial speed u_(0) at an angle alpha with the horizontal. At the highest point of its trajectory, it makes a completely inelastic collision with another identical particle, which was thrown vertically upward from the ground with the same initial speed u_(0). The angle that the composite system makes with the horizontal immediately after the collision is pi//n where 'n' is

Answer»


ANSWER :1
Discussion
13658.

A 20 cm long capillary tube is dipped vertically in water and the liquid rises upto 10 cm. If the entire system is kept in a freely falling platform, the length of water column in the tube will be

Answer»

5 cm
10 cm
15 cm
20 cm

Solution :Height of water in the capillary TUBE, `H=(2T)/(R rho g)`
Here, T = surface tension of water
If the entire system is kept in a freely falling platform, `g=0`
But there will be no change in T.
`therefore T to oo`
So, maximum length of water column in the tube will be 20 cm.
Discussion
13659.

State the rule which is used to find the direction of torque.

Answer»

Solution :The direction of torque is found using right hand rule.This rule says that if fingers of right hand are kept ALONG the POSITION vector with palm facing the direction of the FORCE and when the fingers are CURLED the thumb POINTS to the direction of the torque.
Discussion
13660.

Which one of the following units is not that of mutual inductance?

Answer»

henry
weber
ohm SECOND
`"volt second (ampere)"^(-1)`

Solution :Weber is the unit of magnetic FLUX and not that of MUTUAL INDUCTANCE.
Discussion
13661.

A geostationary satellite orbits the earth at a height of nearly 36,000 km from the surface of earth . What is the potential due to earth.s gravity at the site of this satellite ?( Take the potential energy at infinity to be zero ). Mass of the earth = 6.0 xx10^(24)kg,radius = 6400km , G = 6.67 xx10^(-11) Nm^(2)//kg^2.

Answer»

Solution :Gravitational potential at HEIGHT H from the surface of earth is
`V = -(GM)/((R+h))`
`=((-6.67xx10^(-11))xx(6xx10^(24)))/((6.4 xx10^6+3xx10^6))=-9.4 xx10^(6)J//kg`
Discussion
13662.

Fig, shows a system of two concentric spheres of radii r_(1) and r_(2) and kept at temperature T_(1) and T_(2) (T_(1) gt T_(2)) respectively. Find the expression for radial rate of flow of heat through the substance.

Answer»

Solution :Consider an elementary portion of TWO spheres between two concentric spherical sheels of radius x and `(x+dx)` fig. Let T and `(T-dT)` be the temperature of the inner and outer part of the elementary portion of the shells. Then RATE of FLOW of heat through the elementary portion is

`(dQ)/(dt) = (-KA[T-(T-dT)])/(dx) = (-KA dT)/(dx)`
Here -ve SIGN shown that the heat is lost by the spheres.
Surface area of elementary portion of two spheres,
`A = 4 PI x^(2)`
`:. (dQ)/(dt) = -K 4 pi x^(2) (dT)/(dx)`
or `dT = (-1)/(4 pi K) (dQ)/(dt) x^(-2) dx`
Intergrating both the side within the proper limits, we have
`int_(T_1)^(T_2) dt = -(1)/(4 pi K) (dQ)/(dt) int_(r_1)^(r_2) x^(-2) dx`
`[T]_(T_1)^(T_2) = -(1)/(4 pi K) (dQ)/(dt)[-(1)/(x)]_(r_1)^(r_2)`
`T_(2)-T_(1) = (1)/(4 pi K) (dQ)/(dt)[1/(r_2)-1/(r_2)]`
or `T_(1)-T_(2) = (1)/(4 pi K) (dQ)/(dt)(1/(r_1)-1/(r_2))`
`=(1)/(4 pi K) (dQ)/(dt)(((r_2)-(r_1))/(r_(1)r_(2)))`
`(dQ)/(dt) = (4 pi K (T_(1)-T_(2))r_(1)r_(2))/((r_(2)-r_(1))`.
Discussion
13663.

What is the essential condition for the formation of beats ?

Answer»

SOLUTION :The difference in the FREQUENCY of the TWO waves should not exceed 10.
Discussion
13664.

A force vec(F)_(1) when added to a force vec(F_(2)) = 3i - 5j gives a resulant force bar(F) = -4i. Then bar(F)_(1) is given by

Answer»

`7I + 5J`
`-7i + 5j`
`7i- 5j`
none

Answer :B
Discussion
13665.

Two bodies of masses 5 kg and 3kg are moving towards wach other with 2ms^(-1) and 4ms^(-1) respectively. Then velocity of centre of mass is

Answer»

`0.25 MS^(-1)` towards 3kg
`0.5 ms^(-1)` towards 5KG
`0.25 ms^(-1)` towards 5kg
`0.5 ms^(-1)` towards 3kg

Answer :C
Discussion
13666.

A body of mass 2 kg starts from rest and moves with uniform acceleration. If it acquires a velocity of 20 ms^(-1) in 4s, the power consumed in two seconds is

Answer»

`50 W`
`100 W`
`250W`
`200 W`

ANSWER :B
Discussion
13667.

Rain drops are falling down wards vertically at 4 kmph. For a person moving forward at 3 kmph feels the rain at

Answer»

7kmph
1kmph
5kmph
25kmph

ANSWER :C
Discussion
13668.

Calculate the moment of inertia of a fly wheel, if its angular velocity is increased from 60 r.p.m. to 180 r.p.m. when 100 J of work is done on it.

Answer»

Solution :KINETIC ENERGY `E = (1)/(2)I(omega_(2)^(2)-omega_(1)^(2))`
`100=(1)/(2)I(4pi^(2).9-4pi^(2).1^(2)) "" I=0.633 kg m^(2)`
Discussion
13669.

If the mass of a moving body is decreased by one - third of its initial mass and velocity is tripled, the percentage change in its kinetic energy is

Answer»

5
6
3
2

Answer :A
Discussion
13670.

The breaking stress for a metal wire is 2 xx 10^(8)Nm^(-2). Density of metal =8 xx 10^(3) kg m^(-3). Calculate the maximum length of copper wire which will not break under its own weight, when held in vertical position.

Answer»

SOLUTION :Breaking stress `=(Mg)/(A) = ((AL rho)g)/(A) = L rho g`
`:. L= ("Breaking stress")/( rho g)`
or `L= (2 XX 10^(8))/(8 xx 10^(3) xx 10) or L= 2500m`
Discussion
13671.

The amplitude of a damped oscillator becomes half in one minute. The amplitude after three minutes will be (1)/(x) times the original, then find the value of x.

Answer»

`2XX 3`
`2^3`
`3^2`
`3 xx 2^(2)`

Solution :Amplitude of damped OSCILLATION at time t,
`A(t) = A_(0)e^(-(bt)/(2m))`
After `t= 1 MIN, A(2) = (A_0)/(2)`
`therefore (A_0)/(2) = A_(0)e^(-(b(1))/(2m))`
`therefore (1)/(2)= e^(-(b)/(2m))`
`therefore 2 = e^(-(b)/(2m))"""........."(1)`
Now, after `t= 3 min, A(3) = (A_0)/(x)`
`therefore (A_0)/(x) = A_(0)e^(-(b(3))/(2m))`
`therefore (1)/(x)= e^(-(3b)/(2m))`
`therefore x = e^((3b)/(2m))= (e^((b)/(2m)))^(3)`
`therefore x= 2^(3)` (from equation (1)).
Discussion
13672.

. A raindrop falling from a height .h. above ground, attains a near terminal velocity when it has fallen through a height (3/4)h. Which of the diagrams shown below correctly shows the change in kinetic and potential energy of the drop during its fall up to the ground?

Answer»




ANSWER :B
Discussion
13673.

The resultant of two vectors will be minimum, if they are

Answer»

EQUAL VECTORS
parallel vectors
coplanar vectors
PERPENDICULAR to each other.

ANSWER :D
Discussion
13674.

What is dynamic lift ?

Answer»

SOLUTION :Dynamic lift is the FORCE that acts on a body , such as airplane wing , a hydrofoil or a spinning ball, by virtue ofits motion through a fluid.
In many games suchas cricket , tennis , base- ball , or golf , when a spinning ball deviates from its PARABOLIC trajectory and MOVE through air.
Discussion
13675.

A person is standing on a platform. As engine while approaching the platform blows a whistle , the frequency of which is 100 Hz.The speed of engine is 108 km h^(-1) and speed of sound is 340 ms^(-1).Calculate the appearent frequency of the whistle as heard by the person.

Answer»


ANSWER :109.7 HZ
Discussion
13676.

Which of the following is not correct of radiation ?

Answer»

Wavelength is changedwhile transferring from one to another MEDIUM
Frequency is changed while transferring from one to another medium.
Speed is changed white transferring from one to another medium.
It performs LINEAR motion in GIVEN medium.

SOLUTION :Frequency is property of source, hence it remains constant.
Discussion
13677.

The ratio of the volume expansivity of Helium to pressure expansivity of Hydrogen is

Answer»

1
2
273
1/273

Answer :A
Discussion
13678.

A simple harmonic oscillation is represented by the equation y=0.4 sin ((440t)/7+0.61x) Where 'Y' and 'X' are in m and time 't' in seconds respectively. The value of time period in seconds

Answer»

0.1
0.01
1
10

Answer :A
Discussion
13679.

The triple point of water is a standard fixed point in modern thermometry. Why ? Why melting point of ice or boiling point of water not used as standard fixed points.(as was originally done in celsius scale)

Answer»

Solution :The melting point of ice as well as the boiling point of water changes with CHANGE in pressure. The presence of IMPURITIES ALSO changes the melting and boiling POINTS. However the triple point of water has a unique temperature and is independent of external factors. It is that TEMPERATURES at which water, ice & water vapour co-exist that is 273. 16 K and pressure 0.46 cm of Hg.
Discussion
13680.

Two boats are floating on still worst meditace apart from each other. The best on each boa are standing heling each other and holding a rope, one at each end. When the repels pulled whether by each man separately or both together, the two fronts always meet at a some point. Why?

Answer»

SOLUTION :In this case the two bont and the boatmen constitute a SINGLE system. So, the forces applied by the boatmen are internal forces, in the sense of any external FORCE, the centre of Man of the system of boats remains fixed. As result, the BEST mot always the same point, which is the centre of mass of the system.
Discussion
13681.

Which of the following option is correct for havin a straight line motion represented by displacement - time graph.

Answer»

The object MOVES with constantly increasing velocity from O to A then it moves with constant velocity
Velocity of the object increases uniformly
Average velocity is ZERO.
The graph shown is IMPOSSIBLE.

Answer :C
Discussion
13682.

The radius of gyration of a solid sphere of radius 'R' about its tangential axis is

Answer»

`(7R)/(5)`
`(3R)/(5)`
`Rsqrt((7)/(5))`
`Rsqrt((3)/(5))`

ANSWER :C
Discussion
13683.

A body is thrown vertically upwards at t = 0. It is at a height 80 m at instants t_(1) and t_(2). Also, it is at a height 60 m at instant t_(1) and t_(2). Then:

Answer»

`t_(1) + t_(2) = t'_(1) + t'_(2)`
`t_(1) + t_(2) GT t'_(1) + t'_(2)`
`t_(1) + t_(2) lt t'_(1) + t'_(2)`
NONE of these

Solution :`t_(1) + t_(2) = t'_(1) + t'_(2)` Sum of TIME remain same.
Discussion
13684.

Which one of the following is not a unit of British system of units?

Answer»

foot
metre
pound
second

Solution :AMONG the GIVEN units metre is not a UNIT of british system whereas all other units BELONG to this system.
Discussion
13685.

A brass rod of length 50 cm and diameter 3.0 mm is joined to a steel rod of the same length and diameter. What is the change in length of the combined rod at 250^(@)C, if the original lengths are at 40.0^(@)C ? there a 'thermal stress' developed at the junction ? The ends of the rod are free to expand (Coefficient of linear expansion of brass =2.0xx10^(-5)K^(-1)," steel "=1.2xx10^(-5)K^(-1)).

Answer»

Solution :Increase in length of brass rod,
`Deltal_(1)=alpha_(1)l_(1)DeltaT""[becausel_(1)=50" CM",DeltaT=250-40=210^(@)C]`
`=2xx10^(-5)xx50xx210`
`=420xx50xx10^(-5)`
`=0.21` cm
Increase in length of steel rod,
`Deltal_(2)=alpha_(2)l_(2)DeltaT[becausel_(2)=50" cm"]`
`=1.2xx10^(-5)xx50xx210`
`=0.126` cm
TOTAL increase in combined rod,
`DELTAL=Deltal_(1)+Deltal_(2)`
`=0.21+0.126`
`=0.336`cm
`~~0.34` cm
No, thermal stress is not DEVELOPED at the junction as rods are not clamped at end.
Discussion
13686.

Two cylinders A and B of the same materials have same length. Their radii being in the ratio of 1: 2 respectively. The two are joined end to end as shown in the figure. The upper end of A is rigidly fixed. The lower end of B is twisted through an angle theta, the angle of twist of the cylinder A is :

Answer»

`15/16 THETA `
`16/15 theta`
`16/17 theta `
`17/16 theta `

ANSWER :C
Discussion
13687.

A cylindrical container has a cross sectional area of A_(0) = 1 cm^(2) at 0^(@)C. A scale has been marked on vertical surface of the container which shows correct reading at 0^(@)C. A liquid is poured in the container. When the liquid and container is heated to 100^(@)C, the scale shows the height of the liquid as 83.33 cm. The coefficient of volume expansion for the liquid is gamma = 0.001^(@)C^(-1) and the coefficient of linear expansion of the material of cylindrical container is alpha = 0.0005^(@)C^(-1). A beaker has 300 cm^(3) of same liquid at 0^(@)C. The two liquids are mixed. Find the final temperature of the mixture assuming that heat exchange takes place between the liquids only, and its specific heat capacity is independent of temperature

Answer»


ANSWER :`25^(@)C`
Discussion
13688.

In the arrangement shown in figure, the mass of ball 1 is (n = 1.8) times larger than that of rod 2. The length of rod is l = 1m. The ball is set on the same level as the lower end of the rodand then released, find the time taken by the ball to reach at the level of the upper end of the rod. The masses of pulleys, threads and the friction may be neglected.

Answer»


ANSWER :`1.40 s `
Discussion
13689.

A smooth spherical ball of mass M = 2 kg is resting on two identical blocks A and B as shown in the figure. The blocks are moved apart with same horizontal velocity V = 1 m/s in opposite directions (see figure). (a) Find the normal force applied by each of the blocks on the sphere at the instant separation between the blocks is a = sqrt2R, R = 1.0 m being the radius of the ball. (b) How much force must be applied on each of the two blocks (when a = sqrt2R) so that they do not have any acceleration. Assume that the he horizontal surface is smooth.

Answer»


ANSWER :(a) `(10sqrt2 - 8 ) N`
(B) `(5 - 4sqrt2)N`
Discussion
13690.

A body P moving with a velocity of 20 Kms^(-1) collides with another body of Q of the same mass at rest. After collision the velocity of Q if P comes to rest after collision is

Answer»

`10 Kms^(-1)`
`20 Kms^(-1)`
`30 Kms^(-1)`
`5 Kms^(-1)`

Answer :B
Discussion
13691.

A ladder of mass M and length L stays at rest against a smooth wall. The coefficient of friction between the ground and the ladder is mu (a) Let F_("wall"), W and F_(g) be the force applied by wall, weight of the ladder and force applied by ground on the ladder. Argue to show that the line of action of these three forces must intersect. (b) Using the result obtained in (a) show that line of action of Fg makes an angletan^(-1) (2 tan theta) with the horizontal ground where thetais the angle made by the ladder with the ground. (c) Find the smallest angle that the ladder can make with the ground and not slip. (d) You climb up the ladder, your presence makes the ladder more likely to slip. Where are you at A or B? C is the centre of mass of the ladder.

Answer»


ANSWER :(a) `ALPHA = tan^(-1) (2 tan theta)`
(c) `theta_("min") = tan^(-1) ((1)/(2 MU))`
(d) SLIPPAGE is more likely when at A
Discussion
13692.

One molar of an ideal monoatomic gas at temperature T_0 expands slowly according to the law P/V = constant. If the final temperature is 2T_0heat supplied to the gas is

Answer»

`2RT_0`
`3/2 RT_0`
`RT_0`
`1/2 RT_0`

ANSWER :A
Discussion
13693.

Explain Kepler's first (Law of Orbits) law forplanetary motion.

Answer»

<P>

Solution :`implies`Law of Orbits :
`implies` All planets move in elliptical orbits with the sun situated at one of the foci of the ELLIPSE.

`implies`An ellipse traced out by a PLANET around the sun. The closest point is P and farthest point is A. P is called the Perihelion and A the aphelion. The SEMI major axis is half the distance AP.
`implies`This law was a deviation from the Copernican model which allowed only circular orbits. (The ellipse of which the circle is a special case is a closed CURVE).
Discussion
13694.

If the displacement y of a particle is y=A sin(pt+qx), then dimensional formula of 'Apq' is

Answer»

L
`LT^(-1)`
`T^(-1)`
`L^(-1)T^(-1)`

ANSWER :C
Discussion
13695.

A pendulum clock gives correct time at 20^(0)C at a place where g=9.8ms^(-2). The pendulum consists of a light steel rod connected to a heavy ball. It is taken to a different place where g=9.788ms^(-2). At whattemperaturewill it give correct time?

Answer»


ANSWER :`82^(0)C`
Discussion
13696.

(A) : When a spiral spring is stretched by a force, shearing strain is produced in it. (R) : Shearing strain involves the change of shape of a body

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
13697.

A shell of mass of mass 'm' is projected with a velocity 'v' at an angle 60^(0) to horizontal. When it reacher the maximum height, its angular momentum with respect to point of projection is

Answer»

`(sqrt(3)"MV"^(3))/(8G)`
`("mv"^(3))/(8g)`
`(3"mv"^(3))/(16G)`
`(sqrt(3)"mv"^(3))/(16g)`

Answer :C
Discussion
13698.

What is inertialforce ?

Answer»

Solution :Inertial FORCE that will resist for moving FLUID. It is DUE to obstaclebody in the path of fluid motion
Discussion
13699.

vecA = 2 hati +3 hatJ +4 hatk and vecB =4 hati +5 hatj +3 hatk , then themagnitudes of vecA -vecB…unit

Answer»

21
8.9
3
12.2

Solution :`VEC(A )- vec(B ) = 2hat(I ) +3HAT(j ) + 4hat(k )- 4hat(j )- 5hat(j )- 3hat(k )`
`|vec( A ) - vec( B ) = sqrt(-2)^(2) + (-2)^(2) + (1)^(2))`
`= sqrt(9)`
`=3`
Discussion
13700.

Explain why, an optical pyrometer calibrated for an ideal black body radiation gives a very low value for the temperature of a red hot iron piece in the open, but gives a correct value for the temperature when the same piece is in the furnace

Answer»

SOLUTION :The rate of cooling is faster with the cold surroundings. The rate of cooling does not arise because the temperature of the surrounding furnace is as HIGH as the hot iron piece. HENCE themmJ radiation will be consistent and the READING will be accurate.
Discussion