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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.
| 12151. |
A point object located at a distance of 15 cm from the pole of concave mirror of focal length 10 cm on its principal axis is moving with velocity (8hati+11hatj) cm/s. the velocity of mirror is (4hati+2hatj) cm/s. if the speed of the image in cm/s 4k, find the value of k. |
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| 12152. |
A plate of area 100cm^(2) is placed on the upper surface of castor oil 2 mm thick. Taking the coefficient of viscosity to be 15.5 poise, calculate the horizontal force necessary to move the plate with a velocity of 3 cm/s? |
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Answer» SOLUTION :From `F=-eta A(dV)/(dx)` `F=-15.5xx100xx(-3)/0.2` `=232.5xx10^(2)` dyne `=232.5xx10^(-3)N` |
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| 12153. |
Five moles of neon gas at 2 atm and 27^@Cis adiabatically compressed to 1/3rd its initial volume.[gamma=1.67, C_v = 0.148 cal//g, M = 20.18 gm "mole"] |
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Answer» PRESSURE will CHANGE to 6 atm |
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| 12154. |
The amount of work done by centripetal force on the object moving in a circular path is |
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Answer» zero |
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| 12155. |
A particle of mass m having collided a stationary particle of mass M deviated by an angle pi//2 whereas the particle M recoiled at an angle theta = 30^(@)to the direction of the initial motion of the particle m. How much in percent and in what way has the kinetic energy of this system changed after the collision, if M/m = 5 ? |
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| 12156. |
Starting from rest, a solid sphere rolls down an inclined plane of vertical height h without slipping. If M is the mass and R is the radius of the sphere, write an equation for the moment of inertia of the above sphere about a diameter. |
| Answer» SOLUTION :`I=2/5 MR^2` | |
| 12157. |
Starting from rest, a solid sphere rolls down an inclined plane of vertical height h without slipping. If instead another object of the same mass and radius with a different shape is used in the above experiment, will it rach the bottom with the same or different velocity ? |
| Answer» SOLUTION :DIFFERENT VELOCITY | |
| 12158. |
A simple pendulum perform simple harmonic motion about x=0 with an amplitude A and time period T. The speed of the pendulum at x= (A)/(2) will be………. |
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Answer» `(pi A)/(T)` `=(2pi)/(T) sqrt((3A^2)/(4))= (pi A sqrt(3))/(T)`. |
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| 12159. |
A man with a wriswatch on his hand falls from the top of a tower.Does the watch give the correct time during the free fall?Why? |
| Answer» SOLUTION :WRIST WATCH works based on energy stored in the spring or battery. This energy does not change during its free fall.Hence watch SHOWS CORRECT time during free fall. | |
| 12160. |
Given, for air c_(upsilon) =0.162 cal g^(-1) K^(-1) and density at NTP is 0.001293 g cm^(-3) What is the value of c_p ? |
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Answer» `0.123 CAL g^(-1) K^(-1)` |
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| 12161. |
If a body moving in a circular path with uniform speed, then |
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Answer» the acceleration is DIRECTED towards its centre |
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| 12162. |
A mailbag is to be dropped into a post office from an aeroplane flying horizontally with a velocity of 270 kmh^(-1) at a height of 176.4 m above the ground. How far must the aeroplane be from the post office at the time of dropping the bag so that it directly falls into the post office ? |
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| 12163. |
Two waves passing through a region are represented by y = ( 1.0 m) sin [( pi cm^(-1)) x - ( 50 pi s^(-1))t] and y = ( 1.5 cm) sin [( pi //2 cm^(-1)) x - ( 100 pi s^(-1)) t]. Find the displacement of the particle atx = 4.5 cm at timet = 5.0 ms. |
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Answer» SOLUTION :According to the PRINCIPLE of SUPERPOSITION , each wave produces its disturbance independent of the other and the resultant disturbnce is equal to the vector sum of the individual time ` t= 5.0 MS` due to the waves are, ` y_(1) = ( 1.0 cm) sin [( pi cm^(-1)) ( 4.5 cm) - ( 50 pi s^(-1)) ( 5.0 xx 10^(-3) s)]` ` = ( 1.0 cm) sin [ 4.5 pi - (pi)/( 4)]` `= ( 1.0 cm) sin [ 4 pi + (pi)/( 4)] = ( 1.0 cm)/( sqrt( 2))` and `y_(2)= ( 1.5 cm) sin[( pi//2 cm^(-1)) ( 4.5 cm) - ( 100 pi s^(-1) ( 5.0 xx 10^(-3) s)]` ` = ( 1.5 cm) sin [ 2.25 pi - (pi)/(2))]` `= ( 1.5 cm) sin [ 2 pi - (pi)/(4)] = - ( 1.5 cm) sin ( pi)/(4) = - ( 1.5 cm)/( sqrt (2))` The net displacement is `y = y_(1) + y_(2) = - 0.5 // sqrt(2) cm` ` = - 0.35 cm` |
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| 12164. |
The length of a body is measured as 3.51m, if the acuracy is0.01 m, then the percentage errof in the measurement is |
| Answer» ANSWER :C | |
| 12165. |
A Carnot engine takes 3xx10^(6) ca. of heatfroma reservoir at 627^(@)C, and gives it to a sink at 27^(@)c. The work done by the engine is |
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Answer» `4.2xx10^(6)J` |
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| 12166. |
Theequationof statefor 5gof oxygenat a pressureP andtemepratureT, whenoccupyinga volume V, willbe |
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Answer» `PV =(5//32)RT` |
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| 12167. |
in previous question, if 15 cm of water and spirit each are further poured into the respective arms of the tube. Difference in the level of mercury in the two arms is (Take, relvative density of mercury = 13.6) |
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Answer» <P>0.20 CM `P_(1)=h_(w)rho_(w)g` `=(10+15)xx1xxg` `=25 g`  Pressure of mercury level in another arm due to spirit, `P_(2)=h_(s)rho_(s)g=(12.5+15)xx0.8xxg=22g` As the pressure in water arm is more, therefore, the mercury will rise in spirit arm. Let h be the difference in the levels, of mercury in two arms of U TUBE and `rho` be the density of mercury . Then `P_(1)-P_(2)=hrhog` `25g-22 g=hxx13.6xxg` `therefore h=(3)/(13.6)=0.22cm` |
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| 12168. |
The wavelength of greatest radiation intensity inside a greenhouse is 9.66xx10^(-6) m. Calculate the corresponding temperature. Wien's constant is 0.00289 mK. |
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Answer» SOLUTION :`lamda_(m)=9.66xx10^(-6)` m, B = 0.00289 MK `T =b/lamda_(m)= 0.00289/(9.66xx10^(-6))=299.2` K |
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| 12169. |
According to the conservation linear momentlum which one of the following statementis correct |
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Answer» MOMENTUM before IMPACT = meontum after imapcat |
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| 12170. |
A passing aeroplane sometimes caused the ratting of the windows of house. Given reason. |
| Answer» SOLUTION :When the frequency of sound waves from the ENGINE of an aeroplane MATCHES with the NATURAL frequency of a window, reasonance takes place which caused the RATTLING window. | |
| 12171. |
The speed of a homogenous solid sphere after rolling down an inclined plane of vertical height h, from rest without sliding is |
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Answer» `sqrt(gh)` `:. K_(T)=(5)/(7)mgh=(1)/(2)mv^(2)` `:.v=sqrt((10)/(7))gh`. |
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| 12172. |
Two perfect gasesat temperatures T_1 and T_2are mixed. There is no loss of energy. Find the temperature of mixture if messesof molecules are m and m and the number of molecules in the gases are n_1 and n_2respectively. |
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Answer» Solution :Before mixing , KINETIC energy of all the molecules of TWO gases `3/2kn_1T1+3/2kn_2T_2` If the is temperature of the MIXTURE, the AVERAGE kinetic energy of all molecules of two gases `3/2k(n_1+n_2)T` As there is no loss of energy, THEREFORE, `3/2k(n_1+n_2)T=3/2k(n_1R_1+n_2T_2)` `T=(n_1T_1+n_2T_2)/(n_1+n_2)` |
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| 12173. |
An ideal gas at pressure P is adiabatically compressed so that its density becomes n times the initial value. The final pressure of the gas will be (gamma = (C_(P))/(C_(V))) |
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Answer» <P>`N^(GAMMA)P` |
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| 12174. |
An air bubble of radius 1cm rises from the bottom portion through a liquid of density l.5g/cc at constant speed of 0.25cm/se. If the density of air is neglected the coefficient of viscosity of the liquid is approximately (In pa. s) |
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Answer» 13000 |
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| 12175. |
It is observed that a metal ball rebounds better than a rubber ball. Why? |
| Answer» Solution :When a rubber BALL strikes a SURFACE (say graound), the ball is distorted DUE to the properties of its moleules. This results in generation of large amount of heat in the ball by rubbing of the molecules against each other. But this generally does not happen in case of hard material LIKE metals, ball loses less energy on STRIKING the surface and hence it will rebound better than a rubber ball. | |
| 12176. |
A block of mass m = 1 kg moving on a horizontal surface with speed v_(i)=2ms^(-1) enters a rough patch ranging from x=0.10m to x=2.01m. The retarding force F_(r ) on the block in this range is inversely proportional to x over this range. F_(r )=(-k)/(X) for 0. 1lt x lt 2.01m = 0 for x lt 0.1m and x gt 2.01 m Where k = 0.5 J. What is the final kinetic energy and speed v_(f) of the block as it crosses this patch ? |
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Answer» Solution :From WORK energy therorem `K_(f)-K_(i)=int FDX` `rArr K_(f)=K_(i)+ int_(0.1)^(2.01)((-k))/(x)dx =(1)/(2)mv_(i)^(2)-k1n(x):|_(0.1)^(2.01)` `=(1)/(2)mv_(i)^(2)-k1n(2.01//0.1)=2-0.5 log_(e )(20.1)` `=2-1.5=0.5 J "" v_(f)=sqrt(2K_(f )//m)=1MS^(-1)` |
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| 12177. |
A rectangular block has a square base measuring axxa,and its height is h, moves on a horizontal surface in a direction perpendi-cular to one of the edges. The coefficient of friction is mu. It will topple if |
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Answer» `mugt(H)/(a)` |
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| 12178. |
There are two holes one each along the opposite sides of a wide rectangular tank. The cross section of each hole is 0.01 m^(2) and the vertical distance between the holes is one meter. The tank is filled with water. The net force on the tank in newton when the water flows out of the holes is: (density of water is 1000 "kg/m"^(3) ) |
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Answer» 100 |
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| 12179. |
Given that solar constant on earth surface is S. If sunlight is assumed to be monochroomatic with wavelength lambda and this wavelength is less than the threshold wavelength for earth surface for electron emission. (The solar constant is defined as the intensity of light falling on the earth. Charge on electron is e and velocity of light is c) The photon density (number of photons incidentt per unit volume) near the earth surface is |
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Answer» `(S LAMBDA)/(4hc^(2))` |
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| 12180. |
Given that solar constant on earth surface is S. If sunlight is assumed to be monochroomatic with wavelength lambda and this wavelength is less than the threshold wavelength for earth surface for electron emission. (The solar constant is defined as the intensity of light falling on the earth. Charge on electron is e and velocity of light is c) If quantum efficiency for photoelectric emmission from earth surface is 100% the photoelectric current density from earth surface is |
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Answer» `(SEC)/(h)` |
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| 12181. |
Given that solar constant on earth surface is S. If sunlight is assumed to be monochroomatic with wavelength lambda and this wavelength is less than the threshold wavelength for earth surface for electron emission. (The solar constant is defined as the intensity of light falling on the earth. Charge on electron is e and velocity of light is c) If near the earth surface n_(p) is the photon density and n_(e) is the electron density then we have |
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Answer» `n_(e) gt n_(p)` |
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| 12182. |
A reversible engine converts one-sixth of the heat input into work. When the temperature of the sink is reduced by 62^(@)C, the efficiency of the engine is doubled. The temperature of the source and sink are |
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Answer» `99^(@)C, 27^(@)C` `eta_(2) = 1 - ((T_(2) - 62))/(T_(1)) = 2eta_(1) = (1)/(3)` or `2T_(1) - 3T_(2) = -186` …(II) Solving (i) and (ii), we get `T_(1) = 372 K = 99^(@)C` `T_(2) = (5)/(6)T_(1) = (5)/(6) xx 372 K = 310 K = 37^(@)C` |
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| 12183. |
What is super force ? |
| Answer» SOLUTION :The super force is that single (FIRST) force which SPLITS into the other basic force, YET to be discovered. | |
| 12184. |
In which of the following processes,convection does not take place primarily?(a)Sea and land breeze(b)Boiling of water(c)Warming of glass of bulb due to filament(d)Heating air around a furnace. |
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Answer» Sea and LAND breeze |
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| 12185. |
In the following question select the correct statement. The law of conservation of energy always holds good when: |
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Answer» a BODY moves down a rough plane |
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| 12186. |
Calculate the power of an engine which can pull a mass of 500metric ton up an incline rising 1 in 100 with a velocity of 10 ms^(-1) |
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Answer» Solution :`SIN theta = (1)/(100), V= 10 m//s, m= 500 xx 10^(3)KG` `F= mg sin theta = 500 xx 10^(3) xx 9.8 xx (1)/(100) = 49 xx 10^(3)N` Power `P= FV = 49 xx 10^(3) xx 10= 49 xx 10^(4)` watt = 490 KW |
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| 12187. |
Statement II : Frictional heat generated by themoving ski is the chief factor which promotes sliding in skiing and waxing the ski makes skiing more easy. Statement II : Due to friction energy dissipates in the form of heat. As a result it melts the snow below it. Wax is water repellent. |
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Answer» Statement I is TRUE, statement II is true, statement II is a CORRECT EXPLANATION for statement I. |
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| 12188. |
A car of mass 1000 kg negotiates a banked curve of radius 90 m on a frictionless road. If the banking angle is 45^@, the speed of the car is |
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Answer» `20 ms^(-1)` forbanking` tan theta= (v^2)/(Rg)` `orv= sqrt(Rg tan theta )= sqrt(90 xx10 xx tan 45^@ )= 30ms^(-1)` |
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| 12189. |
Prove vectorially that sum_(S=0)^(S=N-1) "cos"(2piS)/N=0 and sum_(S=0)^(S=N-1) "sin"(2piS)/N=0 |
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| 12190. |
(A) : The velocity of flow of a liquid is smaller when pressure is larger and viceversa. (R ) : According to Bernoulli's theorem, for the stream line flow of an ideal liquid, the total energy per unit mass remains constant. |
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Answer» Both (A) and (R ) are TRUE and (R ) is the correct EXPLANATION of (A) |
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| 12191. |
A bridge over a canal is in the form of a circular arc of radius 5m. The maximum speed with which a motor cycle crosses the bridge without leaving the ground at the highest point is g= 10ms^(-2), (in m/s) |
| Answer» ANSWER :D | |
| 12192. |
A bomb explodeson falling on a horizontal floor. Different parts of the bomb are scattered indifferent directions,each with velocity u. Find the area of the floor which is littered by the fragment. |
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Answer» |
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| 12193. |
The equation of trajectory of a projectile is y = 10x - ((5)/(9)) x^(2). If we assume g = 10 ms^(-2) the range of projectile (in meters) is |
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Answer» 36 |
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| 12194. |
Can a body in free fall be in equilibrium ?Explain ? |
| Answer» SOLUTION :When a BODY was allowed to free FALL in the liquid, if the weight of the body is equal to the BUOYANT force then the body is in EQUILIBRIUM. | |
| 12195. |
When a conservative force does positive work on a body, the potential energy of the body………. |
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Answer» increases |
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| 12196. |
Passengers on a boat should not be allowed to stand up on the boat while crossing a river. Why? |
| Answer» Solution :The centre of GRAVITY of a BOAT with its passengers should be as low as POSSIBLE so that it may always be in a stable EQUILIBRIUM. But it the passengers stand up on the boat, the centre of gravity of the system also moves up. The system then attains an unstable condition. Then, EVEN for a very small tilting the boat may capsize. So the passengers on a boat are not allowed to stand up while crossing a river. | |
| 12197. |
While calculating the volume coefficient of a liquid, we do not consider the pressure, Why? |
| Answer» Solution :Volume coefficient of a liquid DEPENDS on the NATURE of the liquid. If the TEMPERATURE is increased, volume of the liquid changes CONSIDERABLY but not the pressure since the liquids are not compressible. | |
| 12198. |
Calculate the viscous force on a ball of radius Imm moving through a liquid of viscosity 0.2 Nsm^(-2) at a speed of 0.07 ms^(-1) . |
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Answer» Solution :`"Radius of the ball" (a) = 1 mm =1 xx 10^(-3)m` `"Co-effecient of VISCOSITY of LIQUID" (eta)= 0.2 NSM^(-2)` `"SPEED of the ball" (v)= 0.07 ms^(-1)` According to Stoke.s law `"Viscous force" F = 6pietaav` `6 xx 3.14 xx 1 xx 10^(-3) xx 0.2 xx 0.07` `=0.26376 xx 10^(-3) = 2.64 xx 10^(-4) N` |
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| 12199. |
Indicate which pair of physical quantities gives below has not the same units and dimensions? |
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Answer» Momentum and impulse |
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| 12200. |
Do we have an atomic standard of mass? Why? |
| Answer» SOLUTION :No. Because it is not possible to MEASURE MASSES on atomic scale with much PRECISION. | |