Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

The moment of inertia of two rotating bodies Aand B are 1_(A) and I_(B) (I_(A) > I_(B) and their angular moments are equal. Which one has a greater kinetic energy?

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SOLUTION :`K=(L^(2))/(2I) RARR K_(A) GT K_(A)`
Discussion
2.

Find the relative error in Z, if Z = A^(4)B^(1/3)/CD^(3/2).

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SOLUTION :The RELATIVE ERRO in Z is `DeltaZ//Z = 4(DeltaA//A)+(1//3)(DeltaB//B)+(DeltaC//C)+(3//2)(DeltaD/D)`.
Discussion
3.

Gulab Jamuns' (assumed to be spherical) are to be heated in an oven. They available in two size, one twice bigger (in radius) than the other. Pizza (assumed to be discs) are also to be heated in oven. They are also in two sizes, one twice big (in radius) than the other. All four are put together to be heated to oven temperature. Choose the correct option from the following :

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Both size GULAB jamuns will get HEATED in the same time.
SMALLER gulab jamuns are heated before biffer ones.
Smaller PIZZAS are heated before bigger ones.
Bigger pizzas are heated before smaller ones.

Solution :With the given amount of heat, the heating effect is more on a body of smaller surface area than that of LARGER surface area.
Discussion
4.

A train of 150 metre length is going towards north direction at a speed of 10m/s. A parrot flies at the speed of 5m/s towards south direction parallel to the railways track. The time taken by the parrot to cross the train is

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12 sec
8 sec
15 sec
10 sec

Answer :D
Discussion
5.

Explain the propagation of errors in multiplication.

Answer»

SOLUTION :Error in the product of TWO quantities: LET `Delta `A and `Delta ` B be the absolute errors in the two quantities A, and B, respectively. Consider the product Z=AB .
The error `Delta Z`in Z is given by `Z pmDelta Z = (A pmDelta A) (B pmDelta B)`
Dividing LHSby Z and R.H.S by AB, we get,
`1 pm (Delta Z)/(Z ) = 1 pm (Delta B)/(B) pm (Delta A)/(A) pm (Delta A)/(A) . (Delta B)/(B)`
As ` Delta A// A, Delta B//B` are both small quantities, their product TERM `(Delta A)/(A) . (Delta B)/(B)` can be neglected . the maximum fractional error in Z is
`(Delta Z)/(Z) = pm ( (Delta A)/( A) + (Delta B)/( B) )`
Discussion
6.

How do you make a body slide down a smooth inclined plane with constant velocity?

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Solution :By APPLYING an EXTERNAL FORCE `F=mg SINTHETA`, up the plane while the BODY is in motion downwards.
Discussion
7.

A massless platform is kept on a light elastic spring, as shown in the figure. When a particle of 0.1 kg mass is dropped on the pan from a height of 0.24 m, the particle strikes the pan, and the spring compresses by 0.01 m. From what height should the particle be dropped to cause a compression of 0.04 m ?

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SOLUTION :If the PARTICLE is dropped from a height .h. and the spring is compressed by y. Loss in PE of the particle will be mg (h + y) while gain in elastic POTENTIAL energy is `1//2 KY^(2)`.
According to conservation of mechanical energy
`mg(h+y)=(1)/(2)ky^(2)`
As .m. and .K. remain same
`(h_(1)+y_(1))/(h_(2)+y_(2))=((y_(1))/(y_(2)))^(2)`
`(0.24+0.01)/(h_(2)+0.04)=((0.01)/(0.04))^(2), h_(2)=3.96m`
Discussion
8.

More number of readings will reduce …………….

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RANDOM ERROR
systematic error
both (a) and (B)
NEITHER (a) nor (b)

SOLUTION :random error
Discussion
9.

Shown are several curves Fig. Explain with reason, which ones amongst them can be possible trajectories traced by a projectile (nelgect air friction).

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Solution :The nature of trajectory of a particle under the action of gravitational FORCE of earth will be a PARABOLIC RATHER a CONIC section for motion outside the earth with focus lting at the centre of the earth. Only option (C ) meets this requirement.
Discussion
10.

If y_(0) and v denote the sound velocity and the rms velocity of the molecules in a gas, then .....

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`v_(0) = v(3 // gamma)^(1//2)`
`v_(0) = 0`
`v_(0) = v(gamma// 3)^(1//2)`
`v_(0)` and v are not RELATED

SOLUTION :`v_(0) = SQRT((gamma RT)/(M)) , v = sqrt((3RT)/(M)) implies (v_(o))/(v) = sqrt((gamma)/(3)) implies v_(0) = v((gamma)/(2))^(1//2)`
Discussion
11.

Total energy of a system is always conserved , no matter what internal andexternal forces on the body are present .

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Solution :False , the EXTERNAL FORCE on the system MAY increase or DECREASE the total energy of the system.
Discussion
12.

Both terminals of a battery of emf E and internal resistance r are grounded as shown. Select the correct alternative(s).

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Potential DIFFERENCE across A and B is ZERO
Potential difference acorss A and B is E
Current across AB is zero
Current across AB is `(E)/(R)`

Answer :A::D
Discussion
13.

A horizontal square table is standing on four legs fitted at the mid-point of each side. Weight of the table is W. What maximum weight can be placed at any corner of the table, so that it does not overturn ?

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ANSWER :W
Discussion
14.

Consider the following statements (A) Angle of repose is equal to angle of friction(B) Angle of friction is independent of coefficient of friction

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Both A and B are TRUE
Both A and B are FALSE
A is false and B is true
B is false and A is true

ANSWER :D
Discussion
15.

Two identical balls A and B collide head on elastically. If velocities of A and B before the collision are + 0.5 ms^-1 and -0.3 ms^-1 respectively, then their respective velocities after collision are

Answer»

`+ 0.5 ms^-1` and `-0.3 ms^-1`
`+ 0.5 ms^-1` and `+ 0.3 ms^-1`
`+ 0.3 ms^-1` and `- 0.5 ms^-1`
`-0.3 ms^-1` and `+0.5 ms^-1`

ANSWER :D
Discussion
16.

Masses 1 kg, 1.5 kg, 2 kg and M kg are situated at (2, 1, 1), (1, 2,1), (2,-2, 1) and (-1,4,3). If their centre of mass is situated at (1, 1, 3/2), the value of M is

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1 kg
2 kg
1.5 kg
3 kg

ANSWER :C
Discussion
17.

Show that for a particle in linear system, the average K.E. over a period of oscillation equals the average potential energy ever the same period.

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Solution :`=(1)/(T)int_(0)^(T)E_(k)DT` and average P.E. per cycle `=(1)/(T)int_(0)^(T)E_(p)dt`
`"where "E_(k)=(1)/(2)m(a^(2)OMEGA^(2)COS^(2)omegat)`
`and Ep=(1)/(2)m(a^(2)omega^(2)SIN^(2)omegat)`
Since `(1)/(T)int_(0)^(T) sin^(2)omegatdt=(1)/(T)int_(0)^(T)cos^(2)omega t dt=(1)/(2)`
We note that average KE over one cycle `=(1)/(2)[(1)/(2)ma^(2)omega^(2)]=(1)/(4)ma^(2)omega^(2)`
Hence the average PE = average KE over one cycle.
Discussion
18.

Neglecting the air resistance , the time of flight of a projectile is determined by :

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`u_("VERTICAL")`
`u_("HORIZONTAL")`
`U = u_("vertical")^(2)+u_("horizontal")^(2)`
`u = u (u_("vertical")^(2)+u_("horizontal")^(2))^(1//2)`

ANSWER :A
Discussion
19.

(A) : A body can have acceleration even if its velocity is zero at a given instant of time. ( R) : A body is momentarily at rest when it reverses its direction of motion

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Both (A) and ( R) are TURE 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
20.

According to Hooke's law of elasticity, if stress is increased, the ratio of stress to strain will be…………

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INCREASES
DECRESES
becomes zero
remains constnat

Solution :From Hokke.s LAW, from small deformation stress and STRAIN are proportional to each other
`therefore` stress `prop` strain
`therefore` stress `= Y xx` strain
`therefore ("stress")/("strain") = Y,` which REMAIN constant,
Discussion
21.

A large wedge BCD, having its inclined surface at an angle theta = 45^(@) to the horizontal, is travelling horizontally leftwards with uniform velocityu = 10 m//s At some instant a particle is projected vertically up with speed V = 20 m//s from point A on ground lying at some distance right to the lower edge B of the wedge. The particle strikes the incline BC normally, while it was falling. [g = 10 m//s^(2)] (a) Find the distance AB at the instant the particle was projected from A. (b) Find the distance of lower edge B of the wedge from point A at the instant the particle strikes the incline. (c) Trace the path of the particle in the reference frame attached to the wedge.

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ANSWER :(a) `15 m` (B) 15 m (C) PARABOLIC
Discussion
22.

The mass of earth is 9 times of that of Mars The radius of the earth is twice that of Mars. The escape velocity on the earth is 12kms^(-1) , then the escape velocity on the Mars is

Answer»

`5.65 KMS^(-1)`
`6kms^(-1)`
`7kms^(-1)`
`8KMS^(-1)`

ANSWER :A
Discussion
23.

Two bodies are in equilibrium when suspended in water from the arms of a balance. The mass of one body is 36 gm and its density is 9 gm//cm^(2). If the mass of the other body is 48 gm. Its density in gm// cm^(2) is ______

Answer»


ANSWER :3
Discussion
24.

The rms velocity of hydrogen of S.T.P is u ms^(-1)If the gas is heated at constant pressure till its volume is three fold ,what will be its final temperature and rms velocity ?

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SOLUTION :Here `v_1 = u " ms"^(-1) , T_1 = 273K,`
`V_1=V("SAY"), V_2=3 V` USING CHARLE's for constant pressure,
`V_2/V_1=T_2/T_1`
(or) `T_2=V_2/V_1xxT_1`
`=(3V)/Vxx273=819K`
As`V_2/v_1 sqrt((T_2)/(T_1))`
`:.V_2/u=sqrt((819)/273)=sqrt3`
(or) `V_2=sqrt3u ms^(-1)`
Discussion
25.

(A) : When an external force is applied at the centre of mass o a systemof particles then it undergoes translatory motion only.(R ) : The torque of the force acting at c.m, about that c.m. is zero.

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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
26.

In which of the following processes,heat is neither absorbed nor released by a system?

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isochoric
isothermal
ADIABATIC
isobaric

Solution :In an adiabatic PROCESS, `DELTA Q=0`
Discussion
27.

A motorist drives north for 35.0minutes at 85km//h and then stops for 15 minutes. He next continues north , travelling 130km in 2.00hours.What is his total displacement? what is his average velocity?

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Solution :`V_(1)=85kmph,t=35.0min,S_(2)=130km`.
`S_(1)="DISPLACEMENT"=(85)/(60)xx35=43.58km`
`S_(2) =130km`
`s=s_(1)+s_(2)=49.58+130=179.58km`
avetage velocity `V_(ave)=(s_(1)+s_(2)+s_(3))/(t_(1)+t_(2)+t_(3)`
`=(49.58+0+130)/((35)/(60)+(15)/(60)+2)`
`=(179.58xx60)/(170)=(10774.8)/(170)`
`=63.38=63.4 km//hour`
Discussion
28.

In the figure shown m_(1)=1kg, m_(2)=2kg, pulled is ideal. At t=0, both masses touches the ground and string is taut. A force F=2t is applied to pulley (t is in second) then (g=10m//s^(2))

Answer»

`m_(2)` is lifted off the ground at t=20 sec
`m_(1)` is lifted off the groudn at t=10 sec
work done by TENSION in the STRING is `m_(1)` before `m_(2)` is lifted off the groudn is 1250 joule
work done by tension in the string of `m_(1)` before `m_(2)` is lifted off the ground is zero

Answer :A::B::C::D
Discussion
29.

The displacement x of a particle varies with time according to the relation x=(a)/(b)(1-e^(-bt)).Then

Answer»

At t= 1/6, the displacement of the particle in nearly (1/3) (a/b)
The VELOCITY and acceleration of the particle at t= 0 are a and -ab respectively
Both 1 and 2
At t= 1/b, the displacement of the particle is (3/5) (a/b)

Answer :B
Discussion
30.

A lunch travels between two points A and on the opposite banks of a river always following the line AB.The distance S between point A and B is 280 m. The velocity of the river current v=6 m/s is constant over the entire width of the river. The line AB makes an angle alpha=53^(@) with the direction of the current. The angle beta remains the same during the passage from A to B and from B to A. The velocity 'u' and angle beta to the line AB should the launch to be driven to cover the distance AB and back in a time t=128sec is 2p m/sec and 37^(@) q. The values of p and q are

Answer»


ANSWER :4 & 1
Discussion
31.

A motor drives a body along a straight line with a constant force. The power P developed by the motor must vary with time t as

Answer»




ANSWER :A
Discussion
32.

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
33.

The ratio of specific heats of a gas is gamma . The change in internal energy of one mole of gas when the volume changes from v to 2v at constant pressure “p” is

Answer»

`( PV)/( GAMMA-1)`
`pv`
`gamma-1`
`( pv)/( gamma)`

ANSWER :A
Discussion
34.

A ball of relative density 0.8 falls into water from a height of 2m. Find the depth to which the ball will sink (neglect viscous forces)

Answer»

Solution :Retardation of the ball INSIDE the water
`a=("upthrust - weight")/("mass")=("V(1)g - V(0.8)g")/("V(0.8)"),a=(g)/(4)`
Now, `v_(2)^(2)=v_(1)^(2)-2ah^(1)[v_(1)=SQRT(2gh)&v_(2)=0]`
Substituting the values, we get `h=8m`
Discussion
35.

In between two hills of heights 100 m and 92 m respectively. There is a valley of breadth 16 m. If a vehicle jumps from the first hill to the second, what must be its minimum horizontal velocity so that it may not fall into the valley ? Take g=9 ms^(-2)

Answer»


ANSWER :`(12 MS^(-1))`
Discussion
36.

Assertion : The power of an angular depends on mass angular speed torque and angular momentum , then the formula of power is not derived with the help of dimensional method. Reason: In mechanics if a particular quantity depends on more than three quantities then we cannot dimensions the formula of the quantities by the help of dimensions method.

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If both the asseration and reason are true and reason is a true EXPLANATION of the asseration.
If both the asseration and reason are true but the reason is not the correct explanation of asseration.
If the asseration is TURE but reason is false.
If both the asseration and reason are false.

Solution :Here Assertion is correct , but REASION is not true We can drive the formula of a PHYSICAL quantity if a particle DEPENDS upon three quantities.
Discussion
37.

The moments of inertia of two rotating bodies A and B are I_(A) and I_(B)(I_(A) gtI_(B)). If their angular momenta are equal, then

Answer»

Kinetic energy of A = Kinetic energy of B
Kinetic energy of A `gt` Kinetic energy of B
Kinetic energy of A `lt` Kinetic energy of B
Kinetic energy of the TWO BODIES cannot be compared with the GIVEN data.

Solution :`I_(A) omega_(A) = I_(B) omega_(B), therefore (omega_(A))/(omega_(B)) = (I_(B))/(I_(A)) "" … (i)`
Kinetic energy = `(1)/(2) I omega^(2)`
`therefore ((KE)_(A))/((KE)_(B)) = ((1)/(2) I_(A) omega_(A)^(2))/((1)/(2) I_(B) omega_(B)^(2)) = (I_(A))/(I_(B)) XX ((I_(B))/(I_(A)))^(2)= (I_(B))/(I_(A)) ""` (USING (i))
As `I_(A) gt I_(B)` (Given) , `therefore (KE)_(A) lt (KE)_(B)`
Discussion
38.

Among the following choose the wrong statement

Answer»

According to geo-centric THEORY, earth is the centre of UNIVERSE
Copernicus PROPOSED helio-centric theory of the universe
PTOLEMY proposed geo-centric theory of the universe
According to helio-centric theory, earth is the centre of the universe

Answer :D
Discussion
39.

The displacement of SHM particle is x(t)= A cos (omega t+ phi). Its initial displacement is 1 cm and initial velocity is pi(cm)/(sec) and angular frequency is pi s^(-1). Find amplitude.

Answer»

`1 cm`
`SQRT(2) cm`
`2 cm`
`2.5 cm`

Solution :`V= PI cm"/"s""x=1 cm" and " OMEGA pi"/"s` are given
`v= omega sqrt(A^(2)-x^(2)) implies pi = pi sqrt(A^(2)-1)`
`therefore 1= A^(1) -1 implies A= sqrt(2) cm`.
Discussion
40.

In lifting a 10 kg weight to a height of 2m, 230 J energy is spent. Calculate the acceleration with which it was raised

Answer»


ANSWER :`W=mgh+mah=m(g+a)H`
`THEREFORE a=1.5m/s^(2)`
Discussion
41.

Two racing cars of masses m_(1) and m_(2) are moving in circles of radii r_(1) and r_(2) respectively.Their speeds are such that each makes a complete circel in the same time t. The ratio of the angular speed of the first to the second car is

Answer»

`r_(1) : r_(2)`
`m_(1) :m_(2)`
`1:1`
`m_(1)m_(2) : r_(1)r_(2)`

ANSWER :C
Discussion
42.

Figures 10.23(a) and (b) refer to the steady flow of a (non-viscous) liquid. Which of the two figures is incorrect? Why

Answer»

Solution :Fig(a) is incorrect [Reason: at a construction (i.e., where the AREA of cross section of the tube is smaller). Flow SPEED is larger due to mass conservation. CONSEQUENTLY pressure there is smaller ACCORDING to Bernoulli.s EQUATION. We assume the fluid to be incompressible].
Discussion
43.

Definemolarspecificheatcapacity .

Answer»

Solution :The AMOUNT of heat REQUIRED to RISE the temperature of one mole of a substance by 1K or `1^(@) C`at constant volume is CALLED MOLAR specific heat capacity at constant volume.
Discussion
44.

A long steel wire of length 'L' is suspended from the ceiling of a room. A sphere of mass 'm' and radius 'r' is attached to the lower end of the wire. The height of the ceiling is (L + 2r^(1) + 1). When the sphere is made to oscillate as a pendulum, its lowest point just touches the floor. The velocity of the sphere at the lowest point will be ( L gt gt r^(1), 1 and r is the radius of the wire)

Answer»

`SQRT( (pir^(2) YE) /( m) - Lg)`
`sqrt( ( pir^(2) y)/( "me") - Lg)`
`sqrt( (y PI r^(2)e)/( m) )`
None

Answer :A
Discussion
45.

For a simple harmonic oscillator the frequency of oscillation is independent of

Answer»

TIME period
Acceleration
Angular VELOCITY
Amplitude

Answer :D
Discussion
46.

The height of a mercury barometer is 75 cm at sea level and 50 cm at the top of a hill. Ratio of density of mercury to that of air is 10. The height of the hill is

Answer»

`250 m`
`2.5 KM`
`1.25 km`
`750 km`

ANSWER :B
Discussion
47.

A liquid is kept in a cylindrical vessel which is being rotated about a vertical axis through the centre of the circular base. If the radius of the vessel is r and angular velocity of rotation is w, then the different in the heights of the liquid at the centre of the vessel and the edge is

Answer»

`(R omega)/(2G)`
`(r^(2)omega^(2))/(2g)`
`SQRT(2g r omega)`
`(omega^(2))/(2gtr^(2))`

ANSWER :B
Discussion
48.

Two rods of same length having conductivities 60 Wm^(-1)K^(-1),40Wm^(-1)K^(-1) and areas 0.2m^(2),0.3m^(2) are connected in Parallel to each other. The effective conductivity of the combination is

Answer»

`50Wm^(-1)K^(-1)`
`45Wm^(-1)K^(-1)`
`52Wm^(-1)K^(-1)`
`40Wm^(-1)K^(-1)`

ANSWER :D
Discussion
49.

The object at rest suddenly explodes into three parts with the mass ratio 2:1:2. The parts of equal masses move at right angles to each other with equal speed 'v', the speed of the third part after explosion will be :

Answer»

V
`SQRT(2)v`
v/2
`v//sqrt(2)`

ANSWER :D
Discussion
50.

Let us consider an equation (1)/(2)mv^(2)=mgh Where m is the mass of the body. V its velocity , g is the acceleration due to gravity and h is the height . Check whether this equation is dimensionally correct.

Answer»

Solution :The DIMENSIONS of LHS are
`[M] [L T^(-1)]^(2) = [M] [L^(2)T^(-2)]`
`=[M L^(2) T^(-2)]`
The dimensions of RHS are
`[M][L T^(-2)] [L] = [M][L^(2) T^(-2)]`
`=[M L^(2) T^(-2)]`
The dimensions of LHS and RHS are the same and HENCE the equation is DIMENSIONALLY CORRECT.
Discussion