MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 12583 Mcqs, each offering curated multiple-choice questions to sharpen your Joint Entrance Exam - Main (JEE Main) knowledge and support exam preparation. Choose a topic below to get started.
| 8251. |
Figure gives a system of logic gates. From the study of truth table it can be found that to produce a high output (1) at R, we must have |
| A. | X = 0, Y = 1 |
| B. | X = 1, Y = 1 |
| C. | X = 1, Y = 0 |
| D. | X = 0, Y = 0 |
| Answer» D. X = 0, Y = 0 | |
| 8252. |
A star initially has \[{{10}^{40}}\] deuterons. It produces energy via the processes \[_{1}{{H}^{2}}{{+}_{1}}{{H}^{2}}{{\to }_{1}}{{H}^{3}}+p\] \[_{1}{{H}^{2}}{{+}_{1}}{{H}^{3}}{{\to }_{2}}H{{e}^{4}}+n\] The masses of the nuclei are as follows : \[M({{H}^{2}})=2.014\ amu;\ M(p)=1.007\ amu;\] \[M(n)=1.008\ amu;\ M(H{{e}^{4}})=4.001\ amu\] If the average power radiated by the star is \[{{10}^{16}}W\],the deuteron supply of the star is exhausted in a time of the order of [IIT 1993] |
| A. | \[{{10}^{6}}\]sec |
| B. | \[{{10}^{8}}\]sec |
| C. | \[{{10}^{12}}\]sec |
| D. | \[{{10}^{16}}\]sec |
| Answer» D. \[{{10}^{16}}\]sec | |
| 8253. |
A man is watching two trains, one leaving and the other coming in with equal speeds of 4 m/sec. If they sound their whistles, each of frequency 240 Hz, the number of beats heard by the man (velocity of sound in air = 320 m/sec) will be equal to [NCERT 1984; CPMT 1997; MP PET 1999; RPMT 2000; BHU 2004, 05] |
| A. | 6 |
| B. | 3 |
| C. | 0 |
| D. | 12 |
| Answer» B. 3 | |
| 8254. |
A brass cube of side a and density s is floating in mercury of densityr. If the cube is displaced a bit vertically, it executes S.H.M. Its time period will be |
| A. | \[2\pi \sqrt{\frac{\sigma \,a}{\rho \,g}}\] |
| B. | \[2\pi \sqrt{\frac{\rho \,a}{\sigma \,g}}\] |
| C. | \[2\pi \sqrt{\frac{\rho \,g}{\sigma \,a}}\] |
| D. | \[2\pi \sqrt{\frac{\sigma \,g}{\rho \,a}}\] |
| Answer» B. \[2\pi \sqrt{\frac{\rho \,a}{\sigma \,g}}\] | |
| 8255. |
A solid copper sphere (density \[\rho \] and specific heat capacity c) of radius r at an initial temperature 200K is suspended inside a chamber whose walls are at almost 0K. The time required (in \[\mu \]s) for the temperature of the sphere to drop to 100 K is [IIT-JEE 1991] |
| A. | \[\frac{72}{7}\frac{r\rho c}{\sigma }\] |
| B. | \[\frac{7}{72}\frac{r\rho c}{\sigma }\] |
| C. | \[\frac{27}{7}\frac{r\rho c}{\sigma }\] |
| D. | \[\frac{7}{27}\frac{r\rho c}{\sigma }\] |
| Answer» C. \[\frac{27}{7}\frac{r\rho c}{\sigma }\] | |
| 8256. |
In the shown arrangement of the experiment of the meter bridge if AC corresponding to null deflection of galvanometer is x, what would be its value if the radius of the wire AB is doubled [IIT-JEE (Screening) 2003] |
| A. | x |
| B. | x/4 |
| C. | 4x |
| D. | 2x |
| Answer» B. x/4 | |
| 8257. |
A small sphere carrying a charge ?q? is hanging in between two parallel plates by a string of length L. Time period of pendulum is \[{{T}_{0}}\]. When parallel plates are charged, the time period changes to \[T\]. The ratio \[T/{{T}_{0}}\] is equal to [UPSEAT 2003] |
| A. | \[{{\left( \frac{g+\frac{qE}{m}}{g} \right)}^{1/2}}\] |
| B. | \[{{\left( \frac{g}{g+\frac{qE}{m}} \right)}^{3/2}}\] |
| C. | \[{{\left( \frac{g}{g+\frac{qE}{m}} \right)}^{1/2}}\] |
| D. | None of these |
| Answer» D. None of these | |
| 8258. |
Two coherent sources separated by distance\[d\]are radiating in phase having wavelengthl. A detector moves in a big circle around the two sources in the plane of the two sources. The angular position of n = 4 interference maxima is given as |
| A. | \[{{\sin }^{-1}}\frac{n\lambda }{d}\] |
| B. | \[{{\cos }^{-1}}\frac{4\lambda }{d}\] |
| C. | \[{{\tan }^{-1}}\frac{d}{4\lambda }\] |
| D. | \[{{\cos }^{-1}}\frac{\lambda }{4d}\] |
| Answer» C. \[{{\tan }^{-1}}\frac{d}{4\lambda }\] | |
| 8259. |
A spherical surface of radius of curvature R separates air (refractive index 1.0) from glass (refractive index 1.5). The centre of curvature is in the glass. A point object P placed in air is found to have a real image Q in the glass. The line PQ cuts the surface at a point O, and PO = OQ. The distance PO is equal to [IIT JEE 1998; DPMT 2000] |
| A. | 5 R |
| B. | 3 R |
| C. | 2 R |
| D. | 1.5 R |
| Answer» B. 3 R | |
| 8260. |
The following configuration of gate is equivalent to [AMU 1999] |
| A. | NAND |
| B. | XOR |
| C. | OR |
| D. | None of these |
| Answer» C. OR | |
| 8261. |
For uranium nucleus how does its mass vary with volume [IIT-JEE (Screening) 2003] |
| A. | \[m\propto V\] |
| B. | \[m\propto 1/V\] |
| C. | \[m\propto \sqrt{V}\] |
| D. | \[m\propto {{V}^{2}}\] |
| Answer» B. \[m\propto 1/V\] | |
| 8262. |
In order to coincide the parabolas formed by singly ionised ions in one spectrograph and doubly ionized ions in the other Thomson?s mass spectrograph, the electric fields and magnetic fields are kept in the ratios 1 : 2 and 3 : 2 respectively. Then the ratio of masses of the ions is |
| A. | 3 : 4 |
| B. | 1 : 3 |
| C. | 9 : 4 |
| D. | None of these |
| Answer» D. None of these | |
| 8263. |
A conducting rod PQ of length L = 1.0 m is moving with a uniform speed v = 2 m/s in a uniform magnetic field \[B=4.0\,T\] directed into the paper. A capacitor of capacity C = 10 mF is connected as shown in figure. Then |
| A. | qA = + 80 mC and qB = ? 80 mC |
| B. | qA = ? 80 mC and qB = + 80 mC |
| C. | qA = 0 = qB |
| D. | Charge stored in the capacitor increases exponentially with time |
| Answer» B. qA = ? 80 mC and qB = + 80 mC | |
| 8264. |
A silver and a copper voltmeters are connected in parallel across a 6 volt battery of negligible resistance. In half an hour, 1 gm of copper and 2 gm of silver are deposited. The rate at which energy is supplied by the battery will approximately be (Given E.C.E. of copper \[=3.294\times {{10}^{-4}}\,g/C\] and E.C.E. of silver \[=1.118\times {{10}^{-3}}\,g/C)\] |
| A. | 64 W |
| B. | 32 W |
| C. | 96 W |
| D. | 16 W |
| Answer» E. | |
| 8265. |
A wire of density 9´103 kg /m3 is stretched between two clamps 1 m apart and is subjected to an extension of 4.9 ´ 10-4 m. The lowest frequency of transverse vibration in the wire is (Y = 9 ´ 1010 N / m2) [UPSEAT 2000; Pb. PET 2004] |
| A. | 40 Hz |
| B. | 35 Hz |
| C. | 30 Hz |
| D. | 25 Hz |
| Answer» C. 30 Hz | |
| 8266. |
A simple pendulum is hanging from a peg inserted in a vertical wall. Its bob is stretched in horizontal position from the wall and is left free to move. The bob hits on the wall the coefficient of restitution is \[\frac{2}{\sqrt{5}}\]. After how many collisions the amplitude of vibration will become less than 60° [UPSEAT 1999] |
| A. | 6 |
| B. | 3 |
| C. | 5 |
| D. | 4 |
| Answer» C. 5 | |
| 8267. |
A hot metallic sphere of radius \[r\] radiates heat. It's rate of cooling is |
| A. | Independent of \[r\] |
| B. | Proportional to \[r\] |
| C. | Proportional to \[{{r}^{2}}\] |
| D. | Proportional to \[1/r\] |
| Answer» E. | |
| 8268. |
A group of N cells whose emf varies directly with the internal resistance as per the equation EN = 1.5 rN are connected as shown in the figure below. The current I in the circuit is [KCET 2003] |
| A. | 0.51 amp |
| B. | 5.1 amp |
| C. | 0.15 amp |
| D. | 1.5 amp |
| Answer» E. | |
| 8269. |
An infinite number of electric charges each equal to 5 nano-coulomb (magnitude) are placed along X-axis at \[x=1\]cm, \[x=2\]cm, \[x=4\]cm \[x=8\]cm ???. and so on. In the setup if the consecutive charges have opposite sign, then the electric field in Newton/Coulomb at \[x=0\] is \[\left( \frac{1}{4\pi {{\varepsilon }_{0}}}=9\times {{10}^{9}}N-{{m}^{2}}/{{c}^{2}} \right)\] [EAMCET 2003] |
| A. | \[12\times {{10}^{4}}\] |
| B. | \[24\times {{10}^{4}}\] |
| C. | \[36\times {{10}^{4}}\] |
| D. | \[48\times {{10}^{4}}\] |
| Answer» D. \[48\times {{10}^{4}}\] | |
| 8270. |
A beam with wavelength l falls on a stack of partially reflecting planes with separation d. The angle q that the beam should make with the planes so that the beams reflected from successive planes may interfere constructively is (where n =1, 2,??) |
| A. | \[{{\sin }^{-1}}\left( \frac{n\lambda }{d} \right)\] |
| B. | \[{{\tan }^{-1}}\left( \frac{n\lambda }{d} \right)\] |
| C. | \[{{\sin }^{-1}}\left( \frac{n\lambda }{2d} \right)\] |
| D. | \[{{\cos }^{-1}}\left( \frac{n\lambda }{2d} \right)\] |
| Answer» D. \[{{\cos }^{-1}}\left( \frac{n\lambda }{2d} \right)\] | |
| 8271. |
The refractive index of the material of the prism and liquid are 1.56 and 1.32 respectively. What will be the value of q for the following refraction [BHU 2003; CPMT 2004] |
| A. | \[\sin \theta \ge \frac{13}{11}\] |
| B. | \[\sin \theta \ge \frac{11}{13}\] |
| C. | \[\sin \theta \ge \frac{\sqrt{3}}{2}\] |
| D. | \[\sin \theta \ge \frac{1}{\sqrt{2}}\] |
| Answer» C. \[\sin \theta \ge \frac{\sqrt{3}}{2}\] | |
| 8272. |
A heavy nucleus at rest breaks into two fragments which fly off with velocities in the ratio 8 : 1. The ratio of radii of the fragments is [EAMCET (Engg.) 2001] |
| A. | 1 : 2 |
| B. | 1 : 4 |
| C. | 4 : 1 |
| D. | 2 : 1 |
| Answer» B. 1 : 4 | |
| 8273. |
A proton, a deutron and an a-particle having the same momentum, enters a region of uniform electric field between the parallel plates of a capacitor. The electric field is perpendicular to the initial path of the particles. Then the ratio of deflections suffered by them is |
| A. | 1 : 2 : 8 |
| B. | 1 : 2 : 4 |
| C. | 1 : 1 : 2 |
| D. | None of these |
| Answer» B. 1 : 2 : 4 | |
| 8274. |
A conductor ABOCD moves along its bisector with a velocity of 1 m/s through a perpendicular magnetic field of 1 wb/m2, as shown in fig. If all the four sides are of 1m length each, then the induced emf between points A and D is |
| A. | 0 |
| B. | 1.41 volt |
| C. | 0.71 volt |
| D. | None of the above |
| Answer» C. 0.71 volt | |
| 8275. |
If 1 A of current is passed through \[CuS{{O}_{4}}\] solution for 10 seconds, then the number of copper ions deposited at the cathode will be about |
| A. | \[1.6\times {{10}^{19}}\] |
| B. | \[3.1\times {{10}^{19}}\] |
| C. | \[4.8\times {{10}^{19}}\] |
| D. | \[6.2\times {{10}^{19}}\] |
| Answer» C. \[4.8\times {{10}^{19}}\] | |
| 8276. |
A metal wire of linear mass density of 9.8 g/m is stretched with a tension of 10 kg weight between two rigid supports 1 metre apart. The wire passes at its middle point between the poles of a permanent magnet, and it vibrates in resonance when carrying an alternating current of frequency n. The frequency n of the alternating source is [AIEEE 2003] |
| A. | 25 Hz |
| B. | 50 Hz |
| C. | 100 Hz |
| D. | 200 Hz |
| Answer» C. 100 Hz | |
| 8277. |
A simple pendulum has time period T1. The point of suspension is now moved upward according to equation \[y=k{{t}^{2}}\] where\[k=1\,m/se{{c}^{2}}\]. If new time period is T2 then ratio \[\frac{T_{1}^{2}}{T_{2}^{2}}\] will be [IIT-JEE (Screening) 2005] |
| A. | 2/3 |
| B. | 5/6 |
| C. | 6/5 |
| D. | 3/2 |
| Answer» D. 3/2 | |
| 8278. |
Five rods of same dimensions are arranged as shown in the figure. They have thermal conductivities K1, K2, K3, K4 and K5. When points A and B are maintained at different temperatures, no heat flows through the central rod if [KCET 2002] |
| A. | \[{{K}_{1}}={{K}_{4}}\,\text{and}\,\ {{K}_{2}}={{K}_{3}}\] |
| B. | \[{{K}_{1}}{{K}_{4}}={{K}_{2}}{{K}_{3}}\] |
| C. | \[{{K}_{1}}{{K}_{2}}={{K}_{3}}{{K}_{4}}\] |
| D. | \[\frac{{{K}_{1}}}{{{K}_{4}}}=\frac{{{K}_{2}}}{{{K}_{3}}}\] |
| Answer» C. \[{{K}_{1}}{{K}_{2}}={{K}_{3}}{{K}_{4}}\] | |
| 8279. |
Two cylinders A and B fitted with pistons contain equal amounts of an ideal diatomic gas at 300 K. The piston of A is free to move while that of B is held fixed. The same amount of heat is given to the gas in each cylinder. If the rise in temperature of the gas in A is 30 K, then the rise in temperature of the gas in B is [IIT 1998] |
| A. | 30 K |
| B. | 18 K |
| C. | 50 K |
| D. | 42 K |
| Answer» E. | |
| 8280. |
The current in a conductor varies with time t as \[I=2t+3{{t}^{2}}\] where I is in ampere and t in seconds. Electric charge flowing through a section of the conductor during t = 2 sec to t = 3 sec is [Orissa JEE 2003] |
| A. | 10 C |
| B. | 24 C |
| C. | 33 C |
| D. | 44 C |
| Answer» C. 33 C | |
| 8281. |
Two rods of different materials having coefficients of linear expansion \[{{\alpha }_{1}},\,{{\alpha }_{2}}\] and Young's moduli \[{{Y}_{1}}\] and \[{{Y}_{2}}\] respectively are fixed between two rigid massive walls. The rods are heated such that they undergo the same increase in temperature. There is no bending of rods. If \[{{\alpha }_{1}}:{{\alpha }_{2}}=2:3\], the thermal stresses developed in the two rods are equally provided \[{{Y}_{1}}:{{Y}_{2}}\] is equal to [IIT 1989] |
| A. | 2 : 3 |
| B. | 1 : 1 |
| C. | 3 : 2 |
| D. | 4 : 9 |
| Answer» D. 4 : 9 | |
| 8282. |
A satellite S is moving in an elliptical orbit around the earth. The mass of the satellite is very small compared to the mass of earth [IIT 1998] |
| A. | The acceleration of S is always directed towards the centre of the earth |
| B. | The angular momentum of S about the centre of the earth changes in direction but its magnitude remains constant |
| C. | The total mechanical energy of S varies periodically with time |
| D. | The linear momentum of S remains constant in magnitude |
| Answer» B. The angular momentum of S about the centre of the earth changes in direction but its magnitude remains constant | |
| 8283. |
If \[{{W}_{1}},\,{{W}_{2}}\] and \[{{W}_{3}}\] represent the work done in moving a particle from A to B along three different paths 1, 2 and 3 respectively (as shown) in the gravitational field of a point mass m, find the correct relation between \[{{W}_{1}},\,{{W}_{2}}\] and \[{{W}_{3}}\] [IIT-JEE Screening 2003] |
| A. | \[{{W}_{1}}>{{W}_{2}}>{{W}_{3}}\] |
| B. | \[{{W}_{1}}={{W}_{2}}={{W}_{3}}\] |
| C. | \[{{W}_{1}}<{{W}_{2}}<{{W}_{3}}\] |
| D. | \[{{W}_{2}}>{{W}_{1}}>{{W}_{3}}\] |
| Answer» C. \[{{W}_{1}}<{{W}_{2}}<{{W}_{3}}\] | |
| 8284. |
The kinetic energy \[k\] of a particle moving along a circle of radius \[R\] depends on the distance covered \[s\] as \[k=a{{s}^{2}}\] where \[a\] is a constant. The force acting on the particle is [MNR 1992; JIPMER 2001, 02; AMU (Engg.) 1999] |
| A. | \[2a\frac{{{s}^{2}}}{R}\] |
| B. | \[2as{{\left( 1+\frac{{{s}^{2}}}{{{R}^{2}}} \right)}^{1/2}}\] |
| C. | \[2as\] |
| D. | \[2a\frac{{{R}^{2}}}{s}\] |
| Answer» C. \[2as\] | |
| 8285. |
Number of particles is given by \[n=-D\frac{{{n}_{2}}-{{n}_{1}}}{{{x}_{2}}-{{x}_{1}}}\] crossing a unit area perpendicular to X-axis in unit time, where \[{{n}_{1}}\] and \[{{n}_{2}}\] are number of particles per unit volume for the value of \[x\] meant to \[{{x}_{2}}\] and \[{{x}_{1}}\]. Find dimensions of \[D\] called as diffusion constant [CPMT 1979] |
| A. | \[{{M}^{0}}L{{T}^{2}}\] |
| B. | \[{{M}^{0}}{{L}^{2}}{{T}^{-4}}\] |
| C. | \[{{M}^{0}}L{{T}^{-3}}\] |
| D. | \[{{M}^{0}}{{L}^{2}}{{T}^{-1}}\] |
| Answer» E. | |
| 8286. |
In Young's double slit experiment, if monochromatic light is replaced by white light [AIIMS 2001; Kerala PET 2000; KCET 2004] |
| A. | All bright fringes become white |
| B. | All bright fringes have colours between violet and red |
| C. | Only the central fringe is white, all other fringes are coloured |
| D. | No fringes are observed |
| Answer» D. No fringes are observed | |
| 8287. |
A square of side \[3cm\] is placed at a distance of \[25cm\] from a concave mirror of focal length \[10cm.\] The centre of the square is at the axis of the mirror and the plane is normal to the axis. The area enclosed by the image of the square is |
| A. | \[4c{{m}^{2}}\] |
| B. | \[6c{{m}^{2}}\] |
| C. | \[16c{{m}^{2}}\] |
| D. | \[36c{{m}^{2}}\] |
| Answer» B. \[6c{{m}^{2}}\] | |
| 8288. |
The typical ionisation energy of a donor in silicon is [IIT-JEE 1992] |
| A. | \[10.0\,eV\] |
| B. | \[1.0\,eV\] |
| C. | \[0.1\,eV\] |
| D. | \[0.001\,eV\] |
| Answer» D. \[0.001\,eV\] | |
| 8289. |
In hydrogen atom, electron makes transition from n=4 to n=1 level. Recoil momentum of the H atom will be [MP PMT 1994] |
| A. | \[3.4\times {{10}^{-27}}N\text{-}\]sec |
| B. | \[6.8\times {{10}^{-27}}N\text{-}\]sec |
| C. | \[3.4\times {{10}^{-24}}N\text{-}\]sec |
| D. | \[6.8\times {{10}^{-24}}N\text{-}\]sec |
| Answer» C. \[3.4\times {{10}^{-24}}N\text{-}\]sec | |
| 8290. |
A photon and an electron have equal energy E. \[{{\lambda }_{\text{photon}}}/{{\lambda }_{\text{electron}}}\] is proportional to [UPSEAT 2003; IIT-JEE (Screening) 2004] |
| A. | \[\sqrt{E}\] |
| B. | \[1/\sqrt{E}\] |
| C. | \[1/E\] |
| D. | Does not depend upon E |
| Answer» C. \[1/E\] | |
| 8291. |
One 10 V, 60 W bulb is to be connected to 100 V line. The required induction coil has self inductance of value \[(f=50\,Hz)\] [RPET 1997] |
| A. | 0.052 H |
| B. | 2.42 H |
| C. | 16.2 mH |
| D. | 1.62 mH |
| Answer» B. 2.42 H | |
| 8292. |
Two different coils have self-inductance \[{{L}_{1}}=8\]mH, \[{{L}_{2}}=2mH\]. The current in one coil is increased at a constant rate. The current in the second coil is also increased at the same rate. At a certain instant of time, the power given to the two coils is the same. At that time the current, the induced voltage and the energy stored in the first coil are \[{{i}_{1}},\ {{V}_{1}}\]and \[{{W}_{1}}\]respectively. Corresponding values for the second coil at the same instant are \[{{i}_{2}},\ {{V}_{2}}\] and \[{{W}_{2}}\] respectively. Then [IIT JEE 1994] |
| A. | \[\frac{{{i}_{1}}}{{{i}_{2}}}=\frac{1}{4}\] |
| B. | \[\frac{{{i}_{1}}}{{{i}_{2}}}=4\]8 |
| C. | \[\frac{{{W}_{2}}}{{{W}_{1}}}=4\] |
| D. | \[\frac{{{V}_{2}}}{{{V}_{1}}}=\frac{1}{4}\] |
| Answer» D. \[\frac{{{V}_{2}}}{{{V}_{1}}}=\frac{1}{4}\] | |
| 8293. |
Two identical short bar magnets, each having magnetic moment M, are placed a distance of 2d apart with axes perpendicular to each other in a horizontal plane. The magnetic induction at a point midway between them is [IIT-JEE (Screening) 2000] |
| A. | \[\frac{{{\mu }_{0}}}{4\pi }(\sqrt{2})\frac{M}{{{d}^{3}}}\] |
| B. | \[\frac{{{\mu }_{0}}}{4\pi }(\sqrt{3})\frac{M}{{{d}^{3}}}\] |
| C. | \[\left( \frac{2{{\mu }_{0}}}{\pi } \right)\,\frac{M}{{{d}^{3}}}\] |
| D. | \[\frac{{{\mu }_{0}}}{4\pi }(\sqrt{5})\frac{M}{{{d}^{3}}}\] |
| Answer» E. | |
| 8294. |
The magnetic field at the centre of a circular coil of radius r is \[\pi \] times that due to a long straight wire at a distance r from it, for equal currents. Figure here shows three cases : in all cases the circular part has radius r and straight ones are infinitely long. For same current the B field at the centre P in cases 1, 2, 3 have the ratio [CPMT 1989] |
| A. | \[\left( -\frac{\pi }{2} \right):\left( \frac{\pi }{2} \right):\left( \frac{3\pi }{4}-\frac{1}{2} \right)\] |
| B. | \[\left( -\frac{\pi }{2}+1 \right):\left( \frac{\pi }{2}+1 \right):\left( \frac{3\pi }{4}+\frac{1}{2} \right)\] |
| C. | \[-\frac{\pi }{2}:\frac{\pi }{2}:3\frac{\pi }{4}\] |
| D. | \[\left( -\frac{\pi }{2}-1 \right):\left( \frac{\pi }{2}-\frac{1}{4} \right):\left( \frac{3\pi }{4}+\frac{1}{2} \right)\] |
| Answer» B. \[\left( -\frac{\pi }{2}+1 \right):\left( \frac{\pi }{2}+1 \right):\left( \frac{3\pi }{4}+\frac{1}{2} \right)\] | |
| 8295. |
In the circuit shown in figure, the heat produced in 5 ohm resistance is 10 calories per second. The heat produced in 4 resistance is [IIT 1981; UPSEAT 2002] |
| A. | 1 cal / sec |
| B. | 2 cal/sec |
| C. | 3 cal / sec |
| D. | 4 cal/sec |
| Answer» C. 3 cal / sec | |
| 8296. |
In a large room, a person receives direct sound waves from a source 120 metres away from him. He also receives waves from the same source which reach him, being reflected from the 25 metre high ceiling at a point halfway between them. The two waves interfere constructively for wavelength of [Roorkee 1982] |
| A. | 20, 20/3, 20/5 etc |
| B. | 10, 5, 2.5 etc |
| C. | 10, 20, 30 etc |
| D. | 15, 25, 35 etc |
| Answer» B. 10, 5, 2.5 etc | |
| 8297. |
A particle of mass m is executing oscillations about the origin on the x-axis. Its potential energy is \[U(x)=k{{[x]}^{3}}\], where k is a positive constant. If the amplitude of oscillation is a, then its time period T is [IIT-JEE 1998] |
| A. | Proportional to \[\frac{1}{\sqrt{a}}\] |
| B. | Independent of a |
| C. | Proportional to \[\sqrt{a}\] |
| D. | Proportional to \[{{a}^{3/2}}\] |
| Answer» B. Independent of a | |
| 8298. |
During the melting of a slab of ice at 273 K at atmospheric pressure [IIT 1998] |
| A. | Positive work is done by ice-water system on the atmosphere |
| B. | Positive work is done on the ice-water system by the atmosphere |
| C. | The internal energy of the ice-water system increases |
| D. | The internal energy of the ice-water system decreases |
| Answer» C. The internal energy of the ice-water system increases | |
| 8299. |
Solids expand on heating because [CPMT 1990] |
| A. | Kinetic energy of the atoms increases |
| B. | Potential energy of the atoms increases |
| C. | Total energy of the atoms increases |
| D. | The potential energy curve is asymmetric about the equilibrium distance between neighbouring atoms |
| Answer» E. | |
| 8300. |
A wooden block, with a coin placed on its top, floats in water as shown in fig. the distance l and h are shown there. After some time the coin falls into the water. Then [IIT-JEE (Screening) 2002] |
| A. | l decreases and h increases |
| B. | l increases and h decreases |
| C. | Both l and h increase |
| D. | Both l and h decrease |
| Answer» E. | |