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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.
| 201. |
A coil of inductance 40 henry is connected in 0series with a resistance of 8 ohm and the combination is joined to the terminals of a 2 volt battery. The time constant of the circuit is [MP PET 2000] |
| A. | 40 seconds |
| B. | 20 seconds |
| C. | 8 seconds |
| D. | 5 seconds |
| Answer» E. | |
| 202. |
Ampere hour is the unit of [Orissa JEE 2005] |
| A. | Quantity of charge |
| B. | Potential |
| C. | Energy |
| D. | Current |
| Answer» B. Potential | |
| 203. |
Find out the e.m.f. produced when the current changes from 0 to 1 A in 10 second, given L = 10 mH [DCE 2001] |
| A. | 1 V |
| B. | 1 mV |
| C. | 1 mV |
| D. | 0.1 V |
| Answer» C. 1 mV | |
| 204. |
Assertion : The mass of a nucleus can be either less than or more than the sum of the masses of nucleons present in it. Reason : The whole mass of the atom is considered in the nucleus. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» F. | |
| 205. |
If the value of ?g? acceleration due to gravity, at earth surface is \[10\,m/{{s}^{2}}\], its value in \[m/{{s}^{2}}\] at the centre of the earth, which is assumed to be a sphere of radius ?R? metre and uniform mass density is [AIIMS 2002] |
| A. | 5 |
| B. | 10/R |
| C. | 10/2R |
| D. | Zero |
| Answer» E. | |
| 206. |
A light of wavelength \[6000\overset{o}{\mathop{A}}\,\] shines on two narrow slits separated by a distance 1.0 mm and illuminates a screen at a distance 1.5 m away. When one slit is covered by a thin glass plate of refractive index 1.8 and other slit by a thin glass plate of refractive index\[\mu \], the central maxima shifts by 0.1 rad. Both plates have the same thickness of 0.5 mm. The value of refractive index \[\mu \]of the glass is |
| A. | 1.4 |
| B. | l5 |
| C. | 1.6 |
| D. | None of these |
| Answer» D. None of these | |
| 207. |
If the wavelength of the first line of the Balmer series of hydrogen is\[6561\ {AA}\], the wavelength of the second line of the series should be [CPMT 1984; DPMT 2004] |
| A. | \[13122\ {AA}\] |
| B. | \[3280\ {AA}\] |
| C. | \[4860\ {AA}\] |
| D. | \[2187\ {AA}\] |
| Answer» D. \[2187\ {AA}\] | |
| 208. |
Read the assertion and reason carefully to mark the correct option out of the options given below: Assertion : On a rainy day, it is difficult to drive a car or bus at high speed. Reason : The value of coefficient of friction is lowered due to wetting of the surface. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion. | |
| 209. |
X-rays are known to be electromagnetic radiations. Therefore the X-ray photon has [MP PET 1993] |
| A. | Electric charge |
| B. | Magnetic moment |
| C. | Both electric charge and magnetic moment |
| D. | Neither electric charge nor magnetic moment |
| Answer» E. | |
| 210. |
Copper has face centered cubic (fcc) lattice with interatomic spacing equal to \[2.54{AA}\]. The value of the lattice constant for this lattice is [CBSE PMT 2005] |
| A. | \[1.27\,{AA}\] |
| B. | \[5.08\,{AA}\] |
| C. | \[2.54\,{AA}\] |
| D. | \[3.59\,{AA}\] |
| Answer» E. | |
| 211. |
A glass plate 0.40 micron thick is illuminated by a beam of white light normal to the plate. The refractive index of glass is 1.50 and the limits of the visible spectrum are \[{{\lambda }_{V}}=4000\,\overset{o}{\mathop{A}}\,\] and\[{{\lambda }_{R}}=7000\,\overset{o}{\mathop{A}}\,\] The wavelengths that get intensified in the reflected beam are |
| A. | \[\text{4800 }\overset{o}{\mathop{A}}\,\]and \[5200\overset{o}{\mathop{A}}\,\] |
| B. | \[4800\overset{o}{\mathop{A}}\,\]and \[6700\overset{o}{\mathop{A}}\,\] |
| C. | \[4800\overset{o}{\mathop{A}}\,\]only |
| D. | \[5200\overset{o}{\mathop{A}}\,\]only |
| Answer» D. \[5200\overset{o}{\mathop{A}}\,\]only | |
| 212. |
Order of q/m ratio of proton, \[\alpha \]-particle and electron is [AFMC 2004] |
| A. | \[e>p>\alpha \] |
| B. | \[p>\alpha >e\] |
| C. | \[e>\alpha >p\] |
| D. | None of these |
| Answer» B. \[p>\alpha >e\] | |
| 213. |
Wave nature of light follows because [MP PMT 1993] |
| A. | Light rays travel in a straight line |
| B. | Light exhibits the phenomena of reflection and refraction |
| C. | Light exhibits the phenomenon of interference |
| D. | Light causes the phenomenon of photoelectric effect |
| Answer» D. Light causes the phenomenon of photoelectric effect | |
| 214. |
If L is the coherence length and c the velocity of light, the coherent time is [MP PMT 1996] |
| A. | cL |
| B. | \[\frac{L}{c}\] |
| C. | \[\frac{c}{L}\] |
| D. | \[\frac{1}{Lc}\] |
| Answer» C. \[\frac{c}{L}\] | |
| 215. |
Assertion : According to classical theory, the proposed path of an electron in Rutherford atom model will be parabolic. Reason : According to electromagnetic theory an accelerated particle continuously emits radiation. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» F. | |
| 216. |
Assertion : The surface charge densities of two spherical conductors of different radii are equal. Then the electric field intensities near their surface are also equal. Reason : Surface charge density is equal to charge per unit area. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» C. If assertion is true but reason is false. | |
| 217. |
Which one of the following is the weakest kind of bonding in solids [CBSE PMT 1992; KCET 1992] |
| A. | Ionic |
| B. | Metallic |
| C. | Vander Waals |
| D. | Covalent |
| Answer» D. Covalent | |
| 218. |
In a certain system of units, 1 unit of time is 5 sec, 1 unit of mass is 20 kg and 1 unit of length is 10m. In this system, one unit of power will correspond to- |
| A. | 16 watts |
| B. | \[\frac{1}{16}\]watts |
| C. | 25 watts |
| D. | \[\frac{1}{25}\]watts |
| Answer» C. 25 watts | |
| 219. |
In a vessel, as shown in Fig. point P is just visible when no liquid is filled in vessel through a telescope in the air. When liquid is filled in the vessel completely, point Q is visible without moving the vessel or telescope. Find the refractive index of the liquid. |
| A. | \[\frac{\sqrt{14}}{3}\] |
| B. | \[\frac{\sqrt{85}}{5}\] |
| C. | \[\sqrt{2}\] |
| D. | \[\sqrt{3}\] |
| Answer» C. \[\sqrt{2}\] | |
| 220. |
Potassium has a bcc structure with nearest neighbour distance 4.525 Å. Its molecular weight is 39. Its density in kg/m3 is [DCE 1997] |
| A. | 900 |
| B. | 494 |
| C. | 602 |
| D. | 802 |
| Answer» B. 494 | |
| 221. |
A ray of light travelling in a transparent medium falls on a surface separating the medium from air at an angle of incidence of 45°. The ray undergoes total internal reflection. If n is the refractive index of the medium with respect to air, select the possible value (s) of n from the following [IIT-JEE 1998] |
| A. | 1.3 |
| B. | 1.4 |
| C. | 1.5 |
| D. | 1.6 |
| Answer» E. | |
| 222. |
When a ray of light emerges from a block of glass, the critical angle is [KCET 1994] |
| A. | Equal to the angle of reflection |
| B. | The angle between the refracted ray and the normal |
| C. | The angle of incidence for which the refracted ray travels along the glass-air boundary |
| D. | The angle of incidence |
| Answer» D. The angle of incidence | |
| 223. |
A gas at NTP is suddenly compressed to one-fourth of its original volume. If \[\gamma \] is supposed to be \[\frac{3}{2}\], then the final pressure is [BHU 1995] |
| A. | 4 atmosphere |
| B. | \[\frac{3}{2}\] atmosphere |
| C. | 8 atmosphere |
| D. | \[\frac{1}{4}\] atmosphere |
| Answer» D. \[\frac{1}{4}\] atmosphere | |
| 224. |
The phenomenon utilised in an optical fibre is [KCET 1994; AMU 1995; CBSE PMT 2001; DCE 1999, 2000, 01, 02; AIEEE 2002] |
| A. | Refraction |
| B. | Interference |
| C. | Polarization |
| D. | Total internal reflection |
| Answer» E. | |
| 225. |
Assertion : If objective and eye lenses of a microscope are interchanged then it can work as telescope. Reason : The objective of telescope has small focal length. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» E. If assertion is false but reason is true. | |
| 226. |
Assertion : Although the surfaces of a goggle lens are curved, it does not have any power. Reason : In case of goggles, both the curved surfaces have equal radii of curvature. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion. | |
| 227. |
Assertion : The illuminance of an image produced by a convex lens is greater in the middle and less towards the edges. Reason : The middle part of image is formed by undeflected rays while outer part by inclined rays. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion. | |
| 228. |
If the separation between slits in Young?s double slit experiment is reduced to \[\frac{1}{3}rd,\] the fringe width becomes n times. The value of n is [MP PET 2003] |
| A. | 3 |
| B. | \[\frac{1}{3}\] |
| C. | 9 |
| D. | \[\frac{1}{9}\] |
| Answer» B. \[\frac{1}{3}\] | |
| 229. |
The mass and diameter of a planet have twice the value of the corresponding parameters of earth. Acceleration due to gravity on the surface of the planet is [NCERT 1971; Pb. PMT 2000] |
| A. | \[9.8\,m/{{\sec }^{2}}\] |
| B. | \[4.9\,m/{{\sec }^{2}}\] |
| C. | \[980\,m/{{\sec }^{2}}\] |
| D. | \[19.6\,m/{{\sec }^{2}}\] |
| Answer» C. \[980\,m/{{\sec }^{2}}\] | |
| 230. |
Binding energy per nucleon vs mass number curve for nuclei is shown in the Figure. W, X, F and Z are four nuclei indicated on the curve. The process that would release energy is |
| A. | \[Y\to 2Z~\] |
| B. | \[W\to X+Z\,\] |
| C. | \[W\to 2Y\] |
| D. | \[X\to Y+Z\] |
| Answer» D. \[X\to Y+Z\] | |
| 231. |
A variable condenser is permanently connected to a 100 \[V\] battery. If the capacity is changed from \[2\mu \,F\] to \[10\,\mu \,F\], then change in energy is equal to [BHU 2000] |
| A. | \[2\times {{10}^{-2}}\,J\] |
| B. | \[2.5\times {{10}^{-2}}\,J\] |
| C. | \[3.5\times {{10}^{-2}}\,J\] |
| D. | \[4\times {{10}^{-2}}\,J\] |
| Answer» E. | |
| 232. |
In the case of a common emitter transistor amplifier the ratio of the collector current to the emitter current \[{{I}_{c}}/{{I}_{e}}\] is \[0.96\]. The current gain of the amplifier is |
| A. | \[6\] |
| B. | \[48\] |
| C. | \[24\] |
| D. | \[12\] |
| Answer» D. \[12\] | |
| 233. |
A uniform rope of length L and mass mi hangs vertically from a rigid support. A block of mass \[{{m}_{2}}\]is attached to the free end of the rope. A transverse pulse of wavelength \[{{\lambda }_{1}}\] is produced at the lower end of the rope. The wavelength of the pulse when it reaches the top of the rope is \[{{\lambda }_{2}}\] the ratio\[{{\lambda }_{2}}/{{\lambda }_{1}}\] is |
| A. | \[\sqrt{\frac{{{m}_{1}}}{{{m}_{2}}}}\] |
| B. | \[\sqrt{\frac{{{m}_{1}}+{{m}_{2}}}{{{m}_{2}}}}\] |
| C. | \[\sqrt{\frac{{{m}_{2}}}{{{m}_{1}}}}\] |
| D. | \[\sqrt{\frac{{{m}_{1}}+{{m}_{2}}}{{{m}_{1}}}}\] |
| Answer» C. \[\sqrt{\frac{{{m}_{2}}}{{{m}_{1}}}}\] | |
| 234. |
Assertion : Inductance coil are made of copper. Reason : Induced current is more in wire having less resistance. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion. | |
| 235. |
In an experiment with sonometer a tuning fork of frequency 256 Hz resonates with a length of 25 cm and another tuning fork resonates with a length of 16 cm. Tension of the string remaining constant the frequency of the second tuning fork is [KCET 2005] |
| A. | 163.84 Hz |
| B. | 400 Hz |
| C. | 320 Hz |
| D. | 204.8 Hz |
| Answer» E. | |
| 236. |
Which one of the following quantities does not have the unit of force per unit area [MP PMT 1992] |
| A. | Stress |
| B. | Strain |
| C. | Young's modulus of elasticity |
| D. | Pressure |
| Answer» C. Young's modulus of elasticity | |
| 237. |
The fundamental frequency of a sonometre wire is n. If its radius is doubled and its tension becomes half, the material of the wire remains same, the new fundamental frequency will be [BCECE 2005] |
| A. | n |
| B. | \[\frac{n}{\sqrt{2}}\] |
| C. | \[\frac{n}{2}\] |
| D. | \[\frac{n}{2\sqrt{2}}\] |
| Answer» E. | |
| 238. |
A beaker is completely filled with water at 4°C. It will overflow if [EAMCET 1992; BHU 1994; AFMC 2005] |
| A. | Heated above 4°C |
| B. | Cooled below 4°C |
| C. | Both heated and cooled above and below 4°C respectively |
| D. | None of the above |
| Answer» D. None of the above | |
| 239. |
The luminous dials watches are usually made by mixing a zinc sulphide phosphor with an \[\alpha \]- particle emitter. The mass of radium (mass number 226, half-life 1620 years) that is needed to produce an average of 10 \[\alpha \]-particles per second for this purpose is |
| A. | \[2.77\text{ }mg\] |
| B. | \[2.77\text{ }g\] |
| C. | \[2.77\times {{10}^{-23}}g\] |
| D. | \[2.77\times {{10}^{-13}}kg\] |
| Answer» E. | |
| 240. |
A body moves in a straight line along x-axis. Its distance from the origin is given by\[x=9t-3{{t}^{2}}\]. The average velocity between \[t=0\] to \[t=4\] is |
| A. | \[-3\,m{{s}^{-1}}\] |
| B. | \[4\,m{{s}^{-1}}\] |
| C. | \[-16\,m{{s}^{-1}}\] |
| D. | \[-12\,m{{s}^{-1}}\] |
| Answer» B. \[4\,m{{s}^{-1}}\] | |
| 241. |
The change in internal energy of a thermo- dynamical system which has absorbed 2 kcal of heat and done 400 J of work is \[(1\text{ }cal=4.2J)\] |
| A. | 2 kJ |
| B. | 8 kJ |
| C. | 3.5 kJ |
| D. | 5.5 kJ |
| Answer» C. 3.5 kJ | |
| 242. |
If a white light is used in Young?s double slit experiments then a very large number of coloured fringes can be seen [KCET 2001] |
| A. | With first order violet fringes being closer to the central white fringes |
| B. | First order red fringes being closer to the central white fringes |
| C. | With a central white fringe |
| D. | With a central black fringe |
| Answer» D. With a central black fringe | |
| 243. |
In a Young?s double slit experiment, 12 fringes are observed to be formed in a certain segment of the screen when light of wavelength 600 nm is used. If the wavelength of light is changed to 400 nm, number of fringes observed in the same segment of the screen is given by [IIT-JEE (Screening) 2001] |
| A. | 12 |
| B. | 18 |
| C. | 24 |
| D. | 30 |
| Answer» C. 24 | |
| 244. |
In the Young?s double slit experiment with sodium light. The slits are 0.589 m a part. The angular separation of the third maximum from the central maximum will be (given l = 589 mm) [Pb. PMT 2002] |
| A. | \[{{\sin }^{-1}}(0.33\times {{10}^{8}})\] |
| B. | \[{{\sin }^{-1}}(0.33\times {{10}^{-6}})\] |
| C. | \[{{\sin }^{-1}}(3\times {{10}^{-8}})\] |
| D. | \[{{\sin }^{-1}}(3\times {{10}^{-6}})\] |
| Answer» E. | |
| 245. |
In a transformer, the coefficient of mutual inductance between the primary and the secondary coil is 0.2 henry. When the current changes by 5 ampere/second in the primary, the induced e.m.f. in the secondary will be [MP PMT 1989] |
| A. | 5 V |
| B. | 1 V |
| C. | 25 V |
| D. | 10 V |
| Answer» C. 25 V | |
| 246. |
Two particles which are initially at rest, move towards each other under the action of their internal attraction. If their speeds are v and 2v at any instant, then the speed of centre of mass of the system will be: |
| A. | 2v |
| B. | zero |
| C. | 1.5 |
| D. | v |
| Answer» C. 1.5 | |
| 247. |
When a beam of light is used to determine the position of an object, the maximum accuracy is achieved if the light is [AIIMS 2003] |
| A. | Polarised |
| B. | Of longer wavelength |
| C. | Of shorter wavelength |
| D. | Of high intensity |
| Answer» D. Of high intensity | |
| 248. |
If the distance between a point source and screen is doubled, then intensity of light on the screen will become [RPET 1997; RPMT 1999] |
| A. | Four times |
| B. | Double |
| C. | Half |
| D. | One-fourth |
| Answer» E. | |
| 249. |
Huygen wave theory allows us to know [AFMC 2004] |
| A. | The wavelength of the wave |
| B. | The velocity of the wave |
| C. | The amplitude of the wave |
| D. | The propagation of wave fronts |
| Answer» E. | |
| 250. |
In young?s double slit experiment with a source of light of wavelength\[6320\,\,{AA}\], the first maxima will occur when [Roorkee 1999] |
| A. | Path difference is\[9480\,\,{AA}\] |
| B. | Phase difference is 2p radian |
| C. | Path difference is\[6320\,\,{AA}\] |
| D. | Phase difference is p radian |
| Answer» C. Path difference is\[6320\,\,{AA}\] | |