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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.
| 38651. |
A body of mass 0.1 kg is being rotated in a circular path of diameter 1.0 m on a frictionless horizontal plane by means of a string. It performs 10 revolutions in 31.4s. Calculate the centripetal force acting on the body. |
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Answer» |
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| 38652. |
Root mean square velocity of a particle is v at pressure P. If pressure is increased two times, then the r.m.s velocity becomes |
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Answer» `2V` |
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| 38653. |
A particle is in linear simple harmonic motion between two points, A and B, 10 cm apart. Take the direction from A to B as the positive direction and give the signs of velocity, acceleration and force on the particle when it is at 4 cm away from B going towards A. |
| Answer» SOLUTION :`-, -, -` | |
| 38654. |
In the diagrams (i) to (iv) of variation of volume with changing pressure is shown. A gas is taken along the path ABCD . The change in internal energy of the gas will be |
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Answer» Positive in all cases (i) to (iv) |
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| 38655. |
A helicopter is ascending vertically with a speed of 8.0ms^(-1). At a height of 12 m above the earth, a package is dropped from a window. How much time does it take for the package to reach the ground? |
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Answer» `1.23s` |
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| 38656. |
A particle is in linear simple harmonic motion between two points, A and B, 10 cm apart. Take the direction from A to B as the positive direction and give the signs of velocity, acceleration and force on the particle when it is at 2 cm away from B going towards A. |
| Answer» SOLUTION :`-, -, -` | |
| 38657. |
The percentage change in the period of a simple pendulum when it’s a |
| Answer» ANSWER :C | |
| 38658. |
A steel rod of dimensions 4 xx 4cm^(2) is tightly fixed between two supports and is not allowed to expand. It is heated through 2^(@) C. Thermal stress developed is … 10^(6) N//m^(2) (Y=20 xx 10^(10) ) N//m^(2) |
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Answer» `7.2` |
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| 38659. |
Two metallic sphere A and B are made of same material and have got identical surface finish. The mass of sphere A is four times that of B. Both the spheres are heated to the same temperature and placed in a room having lower temperature but thermally insulated from each other. |
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Answer» The ratio of heat loss of A to that of B is `2^(4//3)` |
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| 38660. |
A block of mass 'm' is placed on floor of a lift which is rough. The coefficient of friction between the block and the floor is mu . When the lift falls freely, the block is pulled horizontally on the lift floor. The force of friction is |
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Answer» `mu MG ` |
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| 38661. |
By exerting a certain amount of pressure on an ice block, you |
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Answer» Lower its melting point |
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| 38662. |
A particle is in linear simple harmonic motion between two points, A and B, 10 cm apart. Take the direction from A to B as the positive direction and give the signs of velocity, acceleration and force on the particle when it is at the mid-point of AB going towards A. |
| Answer» SOLUTION :`-, 0,0` | |
| 38663. |
When a running athlete wants to stop immediately which force does he seek? |
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Answer» SOLUTION :KINETIC FRICTION |
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| 38664. |
A rocket is fired vertically with a speed of 5 km s^(-1) from the earth’s surface. How far from the earth does the rocket go before returning to the earth ?Massof the earth = 6.0 x× 10^(24) kg, mean radius of the earth = 6.4 xx 10^(6) m , G = 6.67 xx 10^(-11) " N "m^(2) kg^(-2). |
| Answer» SOLUTION :`8.0 XX 10^(6)` m from the earth.s CENTRE | |
| 38665. |
Explain Anomalous expansion of water. |
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Answer» Solution :Anomalous expansion of water : Thermal expansion of water is non uniform with temperature. It contracts on heating between `0^(@)C` and `4^(@)C`. The volume of a given amount of water decreases as it is cooled from room temperature, until its temperature reaches `4^(@)C`. Below `4^(@)C`, the volume increases, and therefore the density decreases. This means that water has a maximum density at `4^(@)C`.  This property has an important environmental effect : Bodies of water, such as lakes and ponds, freeze at the top first. As a LAKE cools toward `4^(@)C`, water near the surface LOSES energy to the ATMOSPHERE, becomes denser, and sinks, the warmer, less dense water near the bottom rises. However, once the colder water on top reaches temperature below `4^(@)C`, it becomes less dense and remains at the surface, where it freezes. If water did not have this property, lakes and ponds would freeze from the bottom up, which would destroy much of their ANIMAL and plant life. |
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| 38666. |
A particle is in linear simple harmonic motion between two points, A and B, 10 cm apart. Take the direction from A to B as the positive direction and give the signs of velocity, acceleration and force on the particle when it is at the end B. |
| Answer» SOLUTION :`0, -, -` | |
| 38667. |
Explain how a cat is able to-land on its feet when thrown into air ? |
| Answer» Solution :When the cat falls, it stretches its BODY together with the TAIL so that M.I. is increased. By the law of conservation of angular momentum `I OMEGA =a`CONSTANT. So when `I`is LARGE angular velocity | |
| 38668. |
Moment of inertia of a hoop suspended from a peg about the peg is |
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Answer» `MR^(2)` |
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| 38669. |
The image of point P when viewed from top of the slabs will be |
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Answer» 2CM above P |
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| 38670. |
A small body of superdense material, whose ő mass is twice the mass of the earth but whose size is very small compared to the size of the earth, starts from rest at a height H |
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Answer» `SQRT(2H//g)` |
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| 38671. |
At a depth of 5 m below the free surface of a liquid, an air bubble of radius 2 mm is formed. The pressure inside the bubble will be (The surface tension of water is 20 xx 10^(-8)" N/m.") |
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Answer» <P>`2 xx 10^(5) N//m^(2)` `=(10^(5)+10^(3)+10 xx 5)+2 xx (20 xx 10^(-8))/(2 xx 10^(-3))` `=150000 +20 xx 10^(-5)` `=1.5 xx 10^(5)N//m^(2))` |
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| 38672. |
A mass of 2kg oscillates on a spring with force constant 50 N//m. By what vactor does the frequency of oscillation decrease when a damping force with constant b = 12 is introduced? |
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Answer» decreases by 10% |
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| 38673. |
Perhaps the highest temperature material you will ever see is the sun's outer atmosphere, or corona. At a temperature of about 2 times 10^(6@)C " or " 3.6 times 10^(6@)F, the corona glows with a light that is literally unearthly. But because corona is also very thin, its light is rather faint. You can only see the corona during a total solar eclipse when the sun's disk is covered by the moon. Is it accurate to say that the corona contains heat ? |
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Answer» yes |
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| 38674. |
The area of cross-section of railway track is 0.01 m^(2). The temperature variation is 10^(@)C. Coefficient of linear expansion of steel =10^(-5)//""^(@)C. (Young's modulus of steel = 10^(11) Nm^(-2)). Calculate the energy stored per meter in the track. |
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Answer» Solution :LET `alpha`= Coefficient of LINEAR expansion. `:.` Elastic energy `=(1)/(2) xx "stress " xx "strain " xx "volume"` or `U= (1)/(2) xx (Y xx "strain") xx` strain `xx` volume or `U= (1 xx Y xx ("strain")^(2) xx "volume")/(2)` `alpha= (l)/(L xx t) = ("strain")/(t)` `:. alpha= ("CHANGE in LENGTH")/("original length" xx "temperature change")` or strain `= alpha t` `:. U = (Y xx alpha^(2) t^(2) xx ("AREA" xx "length"))/(2)` or `U= (10^(11)xx (10^(-5))^(2) xx (10)^(2) xx 0.01xx 1)/(2) = 5J` `:.` Energy stored `=5J` |
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| 38675. |
A sports car passing a police check post at60 km h^(-1)immediately started slowing down uniformly until its speed was40 km h^(-1). It continued to move at the same speed until it was passed by a police car1 km from the check post. The police car had started from resta t the checkpost at the same instant as the speorts car had passed the chstant as the sports car had passed the check post. The police car had moved with a constant acceleraation until it had passed sports car. Assuming that the time taken by the sports car in slowing down from 60 km h^(-1) to40 km h^(-1) was equal to the time that it travelled at constant speed before passed by the police car, find (a) the time taken by the police car to reach the sports car,(b) the speed of the policecar at the instant when it passed the sports caar, (c ) the time measured from the check post when the speeds of the two cars wer equal. |
Answer» Solution :Refer to fing . 2 (APC). 1 , wher (O) is the check post and cr is moving aong the path ` OX` .  . The car goes from ` O to A` in time (t) with a constant retardation and ` A to B` in time (t) with a constant velocity (= 40 km h^(-1)), where ` OB =1 km`, and at (B), the speorts car is overtaken by POLICE car.Therefore time taken by car to go from ` A to B` is also (t) as PER question. ltBrgt (a) Average velocity of sports car fro motion from ` O to A= ( 60 + 40 0 ///2 = 50 km H^(-1)` :. ( 50 xx t) + 40 xx t = 1 km or t = 1 /(90) h` Time taken by polece car to reach sports car is ` ` =2t = 2 = 2 xx 1/(90) = 1/(45) h = 1 /(45) xx 60 xx 60 = 80 s` (b) Let (a) be he acceleration of police car and (v) be its velocity when it overtakes the sports car. ` Average velocity ` = (0 + v)/2 = v/2` DISTANC e=average velocity xx time taken ` 1 km = v/2 xx 2t =vt =v xx 1/(90)` ` v=90 km h^(-1)` (c ) Taking motion of polece car from ` O to B`, we have ` v=u +at` :. ` 90 =0 = a xx (2t) =a xx ( 1//45)` or ` a= 90 xx 45 km h^(-1)` Let (b) be the retardation of sports car. Takin gmotion of sports car from ` o to A` we have ` u= 60 km h^(-1) , v= 40 km h^(-1)` , ` t= 1 /(90) h,A=b= ?` As ` v=u+ At` :. 40 =60 + b xx 1/(90) or b =- 20 =- 90 km h^(-2)` Let the velocity of the two cars be same at time ` t_1` then veloicty gained by police car in time ` t_1` = velocity gained by sports car in time` t-1)` :. ` 0 + (90 xx 45 ) t-1 =60 - (20 xx 90 0 t_1 or ` t_1 (60)/(90 xx 65) h = (60 xx 60 xx 60 )/ (90 xx 65) = 37 s` . |
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| 38676. |
Consider a pair of identical pendulums, which oscillate with equal amplitude independently such that when one pendulum is at its extreme position making an angle of 2^(@) to the right with the vertical, the other pendulum makes an angle of 1^(@) to the left of the vertical. What is the phase difference between the pendulums? |
Answer» Solution :Given situation are SHOWN in given below figures (i) and (ii)  SUPPOSE both the pendulums follows the below functions, `theta_(1) = theta_(0) sin (omega t+ phi_(1))"""…….."(1)` `theta_(2) = theta_(0) sin (omega t+phi_(2))"""........."(2)` where, `theta_(0)=` amplitude For first pendulum at any time t, `theta_(1)= +theta_(0)""` (Right side) From equation (1) `+ theta_(1)= theta_(0) sin (omega t+phi_(1))` `THEREFORE +1 = sin(omega t+phi_(1))` `therefore omega t + phi_(1) = (pi)/(2)""".........."(3)` Similarly for second pendulum at time t, `theta_(2) = -(theta_0)/(2)""` (left side) From equation (2) `-(theta_0)/(2)= theta_(0) sin (omega t+ phi_(2))` `therefore -(1)/(2)= sin (omega t+ phi_(2))` `therefore omega +phi_(2)= -(pi)/(6)" or "(7pi)/(6)"""......."(4)[i.e. = 2pi-(pi)/(6)]` the difference in phases from equ. (3) and (4) `(omega + phi_(2))-(omega t-phi_(1))= (7pi)/(6)-(pi)/(2)` `therefore phi_(2)-phi_(1)= (4PI)/(6)= (2pi)/(3)` `therefore phi_(2)-phi_(1)= 120^(@)`. |
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| 38677. |
Perhaps the highest temperature material you will ever see is the sun's outer atmosphere, or corona. At a temperature of about 2 times 10^(6@)C " or " 3.6 times 10^(6@)F, the corona glows with a light that is literally unearthly. But because corona is also very thin, its light is rather faint. You can only see the corona during a total solar eclipse when the sun's disk is covered by the moon. What is the highest temperature which can be created on earth for a sufficiently long time ? |
| Answer» Answer :D | |
| 38678. |
An organ pipe of length l vibrates in the fundamental mode,the pressure variation is maximum |
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Answer» at the 2 ENDS |
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| 38679. |
(A) The relative velocity between any two bodies moving in opposite direction is equal to sum of the velocities of two bodies. (R ) : Sometimes relative velocity between two bodies is equal to difference in velocities of the two bodies. |
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Answer» Both (A) and (R) are true and (R) is the CORRECT explanation of (A) |
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| 38680. |
A uniform rod AB of mass .m. length .2a. is allowed to fall under gravity with AB in horizontal. When the speed of the rod is .v., suddenly the end .A. is fixed. Find the angular velocity with which it begins to rotat. |
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Answer» Solution :`L_(1)=L_(2)` `mva = I omega` `mva = (m(2A)^(2))/(3)omega rArr omega = (3V)/(4a)` 
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| 38681. |
A large horizontal turntable is rotating with constant angular speed omega in counterclockwise sense. A person standing at the centre, begins to walk eastward with a constant speed V relative to the table. Taking origin at the centre and X direction to be eastward calculate the maximum X co-ordinate of the person. |
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| 38682. |
A rod of length l and of a uniform cross-sectional area A is made of a material of non-uniform thermal conductivity. Its thermal conductivity is temperature depenndent and varies as K=(B)/(T), where B is a constant. If ends of the rod are maintained at constant temperatures T_(1) and T_(2) with T_(1)gt T_(2), rate of flow of heat in steady state will be : |
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Answer» `"BA"L"log"((T_(2))/(T_(2)))` |
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| 38683. |
Consider an infinite distribution of point masses each of mass m placed on the x-axis a x = r, x = 2r, x = 4r ……….. The gravitational force acting on unit placed at the origin is ______ |
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Answer» `(4GM)/(3R^(2))` |
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| 38684. |
By heating a iron part with flame, first it becomes red, then reddish yellow and at last white. Which can give correct explanation from following ? |
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Answer» NEWTON's law of COOLING |
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| 38685. |
Which of the following statements is correct ? The waves in which the particles of the medium vibrate in direction perpendicular to the direction of wave motion, are known as : |
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Answer» LONGITUDINAL waves |
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| 38686. |
A man weight 80 kg on earth surface. The height above ground where he will weight 40kg is (radius of earth r) |
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Answer» `0.31` TIMES R |
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| 38687. |
When a wire is stretched with a very large force,it breaks which is more elastic,steel or rubber?Why? |
| Answer» SOLUTION :STEEL. Young.s MODULUS of steel is GREATER than that of a RUBBER. | |
| 38688. |
Derive an expression for energy of satellite. |
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Answer» Solution :The total energy of the satellite is the sum of its kinetic energy and the gravitational potential energy. The potential energy of the satellite is, ` U = - (GM_s M_E)/((R_E + h))`...(1) Here `M_s`-mass of the satellite, `M_E` -mass of the EARTH, `R_E`-radius of the Earth. The Kinetic energy of the satellite is `K.E = 1/2 M_(s) v^2`.....(2) Here v is the orbital speed of the satellite and is equal to ` v = sqrt( (GM_E)/((R_E + h)) ` Substituting the value of v in (2) the kinetic energy of the satellite BECOMES, `K.E = 1/2 ( GM_E M_s)/((R_E + h))` Therefore the total energy of the satellite is `E = 1/2 (GM_E M_s)/((R_E + h)) - (GM_s M_E)/((R_E + h))` ` E = (GM_s M_E)/((R_E + h)) ` The total energy IMPLIES that the satellite is bound to the Earth by means of the attractive gravitational force. Note: As h approaches `OO` , the total energy TENDS to zero. Its physical meaning is that the satellite is completely free from the influence of Earth.s gravity and is not bound to Earth at large distance. |
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| 38689. |
Liquid oxygen at 50 K is heated to 300 K at constant pressure of 1 atm. The rate of heating is constant. Which of the following graphs represent the variation of temperature with time ? |
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Answer»
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| 38691. |
Select the odd man out from the following conditions for a body to be in stable equilibrium. |
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Answer» Linear Momentum is zero. |
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| 38692. |
A gun is fired from a place which is at distance 1.2 km from a hill. The echo of the sound s heard back at the same place of firing after 8 second. Find the speed of sound. |
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Answer» Solution :The echo will be heard when the sound reaches back at the place of FIRING. So, the TOTAL distance travelled by sound is `2xx1.2km=2.4km=2400m` SPEED `=(2400m)/(8s)=300ms^(-1)` |
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| 38693. |
The gap between any two rails, each of length 'l' laid on a railway track equals x at 27°C. When the temperature rises to 40°C, the gap closes up. The coefficient of linear expansion of material of the rail is 'alpha'. The length of a rail at 27°C will be |
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Answer» `(x)/( 2 B alpha)` |
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| 38694. |
A cork is submerged in water by a spring to be bottom of a how. The the bowl is kept in an elevatorg moving acceleration downwards. The length of spring. |
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Answer» Increase |
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| 38695. |
If the density of small planet is that of the same as that of the earth while the radius of the planet is 0.2 times that of the Earth, the gravitational acceleration on the surface for the planet is ........ |
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Answer» `0.2`G |
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| 38696. |
A rope is wound several times on a solid cylinder of radius 0.1 m and mass 10 kg. The cylinder is free to rotate about its axis. If the rope is pulled with a force of 10 N, the angular acceleration of the cylinder is |
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Answer» `10" rad s"^(-2)` |
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| 38697. |
For a satellite to attain escape velocity, the percentage increase in its velocity should be |
| Answer» ANSWER :C | |
| 38698. |
The horizontal range of a projectile is 2sqrt(3) times its maximum height. Find the angle of projection. |
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Answer» Solution :If u and `alpha` be the INITIAL velocity of projection and anggle of projection respectively, then the maximum height attained `H_(m)=(u^(2)sin^(2)alpha)/(2g)` and horizontal range `R=(2u^(2)sin alpha cos alpha)/g` ACCORDING to the PROBLEM we can write `(2u^(2)sin alpha cos alpha)/g=2sqrt(3)((u^(2)sin^(2)alpha)/(2g))impliestan alpha=(2/(sqrt(3)))impliesalpha=tan^(-1)(2/(sqrt(3)))` |
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| 38699. |
What is the work done in taking an object of mass 1kg from the surface of the earth to a height equal to the radius of the earth ? (G = 6.67 xx 10^(-11) Nm^(2)//Kg^(2), Radius of the earth = 6400 km, Mass of the earth = 6 xx 10^(24) kg.) |
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Answer» SOLUTION :The work DONE in taking an OBJECT to a height `= (GMm)/(R(R+h)) , ""` Here hR `= (6.67 xx 10^(-11) xx 6 xx 10^(24) xx 1)/(2 xx 6.4 xx 10^(6)) = 3.127 xx 10^(7)J`. |
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| 38700. |
If potential energy of a satellite is -8xx10^9J, then its binding energy is …... . |
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Answer» |
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