MCQOPTIONS
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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.
| 1401. |
Assertion : In a S.H.M., kinetic and potential energies become equal when the displacement is \[1/\sqrt{2}\] times the amplitude. Reason : In SHM, kinetic energy is zero when potential energy is maximum. |
| 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. | |
| 1402. |
When a plane mirror is placed horizontally on a level ground at a distance of 60 m from the foot of a tower, the top of the tower and its image in the mirror subtend an angle of \[{{90}^{o}}\] at the eye. The height of the tower will be |
| A. | 30 m |
| B. | 60 m |
| C. | 90 m |
| D. | 120 m |
| Answer» C. 90 m | |
| 1403. |
A spherical concave mirror of focal length 10 cm is cut in two equal halves and is separated by a distance 4 mm as shown. A small object is kept at 30 cm from the mirrors and between the two halves as shown. The distance between the images by halves of mirror will be |
| A. | 4 mm |
| B. | 6 mm |
| C. | 9 mm |
| D. | 12 mm |
| Answer» C. 9 mm | |
| 1404. |
A man is sitting in a room at 2 m from a wall \[{{W}_{1}}\] wants to see the full height of the wall \[{{W}_{2}}\] behind him 4 m high and 6 m away from the facing wall \[{{W}_{1}}\]. What is the minimum vertical length of mirror on the facing wall required for the purpose? |
| A. | 4 m |
| B. | 2 m |
| C. | 3 m |
| D. | 1 m |
| Answer» E. | |
| 1405. |
If a body of mass 200 g falls from a height 200 m and its total P.E. is converted into K.E. at the point of contact of the body with earth surface, then what is the decrease in P.E. of the body at the contact \[(g=10\,m/{{s}^{2}})\] [AFMC 1997] |
| A. | 200 J |
| B. | 400 J |
| C. | 600 J |
| D. | 900 J |
| Answer» C. 600 J | |
| 1406. |
A solid sphere of radius R is placed on a smooth horizontal surface. A horizontal force F is applied at height h from the lowest point. For the maximum acceleration of the centre of mass, |
| A. | \[h=R\] |
| B. | \[h=2R\] |
| C. | \[h=0\] |
| D. | The acceleration will be same whatever h maybe |
| Answer» E. | |
| 1407. |
Hairs of shaving brush cling together when it is removed from water due to |
| A. | Force of attraction between hair |
| B. | Surface tension |
| C. | Viscosity of water |
| D. | Characteristic property of hairs |
| Answer» C. Viscosity of water | |
| 1408. |
Two quantities A and B have same dimensions which mathematical operation given below is physically meaningful? |
| A. | \[A/B\] |
| B. | \[A+{{B}^{2}}\] |
| C. | \[{{A}^{2}}-B\] |
| D. | \[A={{B}^{2}}\] |
| Answer» B. \[A+{{B}^{2}}\] | |
| 1409. |
Three conducting rods of same material and cross-section are shown in figure. Temperatures of A, D and C are maintained at \[20{}^\circ C,\text{ }90{}^\circ C\] and \[0{}^\circ C\]. The ratio of lengths of BD and BC if there is no heat flow in AB is: |
| A. | 44379 |
| B. | 44234 |
| C. | 44236 |
| D. | 44441 |
| Answer» C. 44236 | |
| 1410. |
In diode, when there is saturation current, the plate resistance \[({{r}_{p}})\] is [AIIMS 1997; Haryana PMT 2000] |
| A. | Zero |
| B. | Infinite |
| C. | Some finite quantity |
| D. | Data is insufficient |
| Answer» C. Some finite quantity | |
| 1411. |
When a tuning fork produces sound waves in air, which one of the following is same in the material of tuning fork as well as in air [AFMC 2005] |
| A. | Wavelength |
| B. | Frequency |
| C. | Velocity |
| D. | Amplitude |
| Answer» C. Velocity | |
| 1412. |
The disc of a siren containing 60 holes rotates at a constant speed of 360 rpm. The emitted sound is in unison with a tuning fork of frequency [KCET 2005] |
| A. | 10 Hz |
| B. | 360 Hz |
| C. | 216 Hz |
| D. | 6 Hz |
| Answer» C. 216 Hz | |
| 1413. |
The patient is asked to drink \[BaS{{O}_{4}}\]for examining the stomach by X-rays because X-rays are |
| A. | Reflected by heavy atoms |
| B. | Refracted by heavy atoms |
| C. | Less absorbed by heavy atoms |
| D. | More absorbed by heavy atoms |
| Answer» E. | |
| 1414. |
A tuning fork makes 256 vibrations per second in air. When the velocity of sound is 330 m/s, then wavelength of the tone emitted is [KCET 1994; AFMC 1998; MH CET 1999; CBSE PMT 1999] |
| A. | 0.56 m |
| B. | 0.89 m |
| C. | 1.11 m |
| D. | 1.29 m |
| Answer» E. | |
| 1415. |
A diesel engine takes in 5 moles of air at \[20{}^\circ C\] and 1 atm, and compresses it adiabatically to \[\frac{1}{10}\text{th}\] of the original volume. If air is diatomic then work done and change in internal energy is |
| A. | - 46 kJ, 46 kJ |
| B. | 36 kJ, - 36 kJ |
| C. | 46 kJ, - 46 kJ |
| D. | - 36 kJ, 36 kJ |
| Answer» B. 36 kJ, - 36 kJ | |
| 1416. |
A gas undergoes a process in which its pressure p and volume V are related as \[V{{p}^{n}}=\] constant the bulk modulus for the gas in the process is |
| A. | np |
| B. | \[{{p}^{1/n}}\] |
| C. | \[\frac{p}{n}\] |
| D. | \[{{p}^{n}}\] |
| Answer» D. \[{{p}^{n}}\] | |
| 1417. |
A monatomic gas undergoes a process given by \[2dU+3dW=0,\] then the process is |
| A. | isobaric |
| B. | adiabatic |
| C. | isothermal |
| D. | none of these |
| Answer» C. isothermal | |
| 1418. |
A Carnot engine works between a source and a sink maintained at constant temperatures \[{{T}_{1}}\] and \[{{T}_{2}}\], For efficiency to be the greatest |
| A. | \[{{T}_{1}}\] and \[{{T}_{2}}\], should be high |
| B. | \[{{T}_{1}}\] and \[{{T}_{2}}\] should be low |
| C. | \[{{T}_{1}}\] should be low and \[{{T}_{2}}\] should be high |
| D. | \[{{T}_{1}}\] should be high and \[{{T}_{2}}\] should be low |
| Answer» E. | |
| 1419. |
Assertion : The threshold frequency of photoelectric effect supports the particle nature of sunlight. Reason : If frequency of incident light is less than the threshold frequency, electrons are not emitted from metal 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» C. If assertion is true but reason is false. | |
| 1420. |
Rays of light from Sun falls on a biconvex lens of focal length f and the circular image of Sun of radius r is formed on the focal plane of the lens. Then |
| A. | area of image is \[\pi {{r}^{2}}\] and area is directly proportional of |
| B. | area of image is \[\pi {{r}^{2}}\] and area is directly proportional to \[{{f}^{2}}\] |
| C. | intensity of image increases if f is increased |
| D. | if lower half of the lens is covered with black paper area will become half |
| Answer» C. intensity of image increases if f is increased | |
| 1421. |
The amplitude of velocity of a particle is given by, \[{{V}_{m}}={{V}_{0}}/(a{{\omega }^{2}}-b\omega +c)\] where \[{{V}_{0}}\], a, b and c are positive: The condition for a single resonant frequency is |
| A. | \[{{b}^{2}}<4ac\] |
| B. | \[{{b}^{2}}=4ac\] |
| C. | \[{{b}^{2}}=5ac\] |
| D. | \[{{b}^{2}}=7ac\] |
| Answer» C. \[{{b}^{2}}=5ac\] | |
| 1422. |
Four cubes of ice at \[-10{}^\circ C\] each one gm is taken out from the refrigerator and are put in 150 gm of water at \[20{}^\circ C\]. The temperature of water when thermal equilibrium is attained. Assume that no heat is lost to the outside and water equivalent of container is 46 gm. (Specific heat capacity of water \[=\text{ }1\text{ }cal/gm-{}^\circ C\], Specific heat capacity of ice \[=\text{ }0.5\text{ }cal/gm-{}^\circ C\], Latent heat of fusion of ice \[=\text{ }80\text{ }cal/gm)\] |
| A. | \[0{}^\circ C\] |
| B. | \[-10{}^\circ C\] |
| C. | \[17.9{}^\circ C\] |
| D. | None |
| Answer» D. None | |
| 1423. |
The freezing point on a thermometer is marked as -\[{{20}^{\circ }}\]and the boiling point as \[{{130}^{\circ }}\]. A temperature of human body \[({{34}^{\circ }}C)\]on this thermometer will be read as: |
| A. | \[{{31}^{\circ }}\] |
| B. | \[{{51}^{\circ }}\] |
| C. | \[{{20}^{\circ }}\] |
| D. | none of these |
| Answer» B. \[{{51}^{\circ }}\] | |
| 1424. |
The activity of a radioactive sample is \[{{A}_{1}}\] at time \[{{t}_{1}}\] and \[{{A}_{2}}\] at time\[{{t}_{2}}\]. If \[\tau \] is average life of sample then the number of nuclei decayed in time (\[{{t}_{2}}-{{t}_{1}}\]) is |
| A. | \[{{A}_{1}}{{t}_{1}}-{{A}_{2}}{{t}_{2}}\] |
| B. | \[\frac{\left( {{A}_{2}}-{{A}_{1}} \right)}{2}\tau \] |
| C. | \[\left( {{A}_{1}}-{{A}_{2}} \right)\left( {{t}_{2}}-{{t}_{1}} \right)\] |
| D. | \[\left( {{A}_{1}}-{{A}_{2}} \right)\tau .\] |
| Answer» E. | |
| 1425. |
Dynamo core is laminated because [MP PET 1995] |
| A. | Magnetic field increases |
| B. | Magnetic saturation level in core increases |
| C. | Residual magnetism in core decreases |
| D. | Loss of energy in core due to eddy currents decreases |
| Answer» E. | |
| 1426. |
The potentials of the two plates of capacitor are +10V and ?10 V. The charge on one of the plates is 40 C. The capacitance of the capacitor is [AFMC 2005] |
| A. | 2 F |
| B. | 4 F |
| C. | 0.5 F |
| D. | 0.25 F |
| Answer» B. 4 F | |
| 1427. |
Two bodies of masses m and 2m have same momentum. Their respective kinetic energies \[{{E}_{1}}\] and \[{{E}_{2}}\] are in the ratio [MP PET 1997; KCET 2004] |
| A. | 1 : 2 |
| B. | 2 : 1 |
| C. | \[1:\sqrt{2}\] |
| D. | 1 : 4 |
| Answer» C. \[1:\sqrt{2}\] | |
| 1428. |
If \[E=at+b{{t}^{2}},\] what is the temperature of inversion [DCE 2003] |
| A. | \[-\frac{a}{2b}\] |
| B. | \[+\frac{a}{2b}\] |
| C. | \[-\frac{a}{b}\] |
| D. | \[+\frac{a}{b}\] |
| Answer» B. \[+\frac{a}{2b}\] | |
| 1429. |
Serious draw back of the semiconductor device is [Pb. PMT 2004] |
| A. | They cannot be used with high voltage |
| B. | They pollute the environment |
| C. | They are costly |
| D. | They do not last for long time |
| Answer» B. They pollute the environment | |
| 1430. |
The sum of two forces acting at a point is 16 N. If the resultant force is 8 N and its direction is perpendicular to minimum force then the forces are [CPMT 1997] |
| A. | 6 N and 10 N |
| B. | 8 N and 8 N |
| C. | 4 N and 12 N |
| D. | 2 N and 14 N |
| Answer» B. 8 N and 8 N | |
| 1431. |
A charge of \[{{10}^{-9}}C\] is placed on each of the 64 identical drops of radius \[2cm\]. They are then combined to form a bigger drop. Find its potential [MP PET 1997] |
| A. | \[7.2\times {{10}^{3}}V\] |
| B. | \[7.2\times {{10}^{2}}V\] |
| C. | \[1.44\times {{10}^{2}}V\] |
| D. | \[1.44\times {{10}^{3}}V\] |
| Answer» B. \[7.2\times {{10}^{2}}V\] | |
| 1432. |
Assertion : The positively charged nucleus of an atom has a radius of almost \[{{10}^{-15}}m.\] Reason : In a-particle scattering experiment, the distance of closest approach for a-particles is ≃\[{{10}^{-15}}m.\] |
| 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. | |
| 1433. |
Transfer characteristics [output voltage \[({{V}_{0}})\] vs input voltage \[({{V}_{1}})\]] for a base biased transistor in CE configuration is as shown in the figure. For using transistor as a switch, it is used |
| A. | in region (III) |
| B. | both in region (I) and (II) |
| C. | in region (II) |
| D. | in region (I) |
| Answer» C. in region (II) | |
| 1434. |
Assertion : Electromagnets are made of soft iron. Reason : Coercivity of soft iron is small. |
| 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. | |
| 1435. |
A gas expands with temperature according to the relation \[V=k{{T}^{2/3}}\]. Calculate work done when the temperature changes by 60 K? |
| A. | 10 R |
| B. | 30 R |
| C. | 40 R |
| D. | 20 R |
| Answer» D. 20 R | |
| 1436. |
From a disc of radius R and mass M, a circular hole of diameter R, whose rim passes through the centre is cut. What is the radius of gyration of the remaining part of the disc about a perpendicular axis, passing through the centre? |
| A. | \[\frac{13}{2}R\] |
| B. | \[\sqrt{\frac{13}{16}R}\] |
| C. | \[\frac{11}{3}R\] |
| D. | \[\sqrt{\frac{13}{9}R}\] |
| Answer» C. \[\frac{11}{3}R\] | |
| 1437. |
Two rigid boxes containing different ideal gases are placed on a table. Box A contains one mole of nitrogen at temperature \[{{T}_{0}},\] While Box B contains one mole of helium at temperature (7/3) \[{{T}_{0}}\]. The boxes are then put into thermal contact with each other and heat flows between them until the gases reach a common final temperature (Ignore the heat capacity of boxes). Then, the final temperature of the gases, \[{{T}_{f}},\] in term of \[{{T}_{0}}\] is |
| A. | \[{{T}_{f}}=\frac{7}{3}{{T}_{0}}\] |
| B. | \[{{T}_{f}}=\frac{3}{2}{{T}_{0}}\] |
| C. | \[{{T}_{f}}=\frac{5}{2}{{T}_{0}}\] |
| D. | \[{{T}_{f}}=\frac{3}{7}{{T}_{0}}\] |
| Answer» C. \[{{T}_{f}}=\frac{5}{2}{{T}_{0}}\] | |
| 1438. |
When a mass m is attached to a spring, it normally extends by 0.2 m. The mass m is given a slight addition extension and released, then its time period will be [MH CET 2001] |
| A. | \[\frac{1}{7}\]sec |
| B. | 1 sec |
| C. | \[\frac{2\pi }{7}\]sec |
| D. | \[\frac{2}{3\pi }\]sec |
| Answer» D. \[\frac{2}{3\pi }\]sec | |
| 1439. |
743 J of heat energy is added to raise the temperature of 5 mole of an ideal gas by 2 K at constant pressure. How much heat energy is required to raise the temperature of the same mass of the gas by 2 K at constant volume? |
| A. | 826 J |
| B. | 743 J |
| C. | 660 J |
| D. | 620 J |
| Answer» D. 620 J | |
| 1440. |
If a body of mass 0.98 kg is made to oscillate on a spring of force constant 4.84 N/m, the angular frequency of the body is [CBSE PMT 2001] |
| A. | 1.22 rad/s |
| B. | 2.22 rad/s |
| C. | 3.22 rad/s |
| D. | 4.22 rad/s |
| Answer» C. 3.22 rad/s | |
| 1441. |
An object is attached to the bottom of a light vertical spring and set vibrating. The maximum speed of the object is 15 cm/sec and the period is 628 milli-seconds. The amplitude of the motion in centimeters is [EAMCET 2003] |
| A. | 3.0 |
| B. | 2.0 |
| C. | 1.5 |
| D. | 1.0 |
| Answer» D. 1.0 | |
| 1442. |
The rectangular surface of area \[8 cm\times 4 cm\]of a black body at temperature \[127{}^\circ C\] emits energy E per second. If the length and breadth are reduced to half of the initial value and the temperature is raised to \[327{}^\circ C\], the rate of emission of energy becomes |
| A. | \[\frac{3}{8}\operatorname{E}\] |
| B. | \[\frac{81}{16}\operatorname{E}\] |
| C. | \[\frac{9}{16}\operatorname{E}\] |
| D. | \[\frac{81}{64}\operatorname{E}\] |
| Answer» E. | |
| 1443. |
What should be the angular speed of earth, so that body lying on equator may appear weightlessness \[(g=10\,m/{{s}^{2}},\,\,R=6400\,km)\] [Pb. PET 2000] |
| A. | \[\frac{1}{800}rad/s\] |
| B. | \[\frac{1}{400}rad/s\] |
| C. | \[\frac{1}{600}rad/s\] |
| D. | \[\frac{1}{100}rad/s\] |
| Answer» B. \[\frac{1}{400}rad/s\] | |
| 1444. |
A tangential force of 20 N is applied on a cylinder of mass 4 kg and moment of inertia \[0.02\,kg\,{{m}^{2}}\] about its own axis. If the cylinder rolls without slipping, then linear acceleration of its centre of mass will be |
| A. | \[6.7m/{{s}^{2}}\] |
| B. | \[10m/{{s}^{2}}\] |
| C. | \[3.3m/{{s}^{2}}\] |
| D. | None of these |
| Answer» B. \[10m/{{s}^{2}}\] | |
| 1445. |
In a Young's double slit experiment with light of wavelength \[\beta \], fringe pattern on the screen has fringe width\[\beta \]. When two thin transparent glass (refractive index u) plates of thickness\[{{t}_{1}}\] and\[{{t}_{2}}\]\[({{t}_{1}}>{{t}_{2}})\] are placed in the path of the two beams respectively, the fringe pattern will shift by a distance |
| A. | \[\frac{\beta (\mu -1)}{\lambda }\left( \frac{{{t}_{1}}}{{{t}_{2}}} \right)\] |
| B. | \[\frac{\mu \beta }{\lambda }\frac{{{t}_{1}}}{{{t}_{2}}}\] |
| C. | \[\frac{\beta (\mu -1)}{\lambda }({{t}_{1}}-{{t}_{2}})\] |
| D. | \[(\mu -1)\frac{\lambda }{\beta }({{t}_{1}}+{{t}_{2}})\] |
| Answer» D. \[(\mu -1)\frac{\lambda }{\beta }({{t}_{1}}+{{t}_{2}})\] | |
| 1446. |
Assertion : When temperature of cold junction of a thermocouple is lowered, the value of neutral temperature of this thermocouple is raised. Reason : When the difference of temperature of two junction is raised, more thermo e.m.f. is produced. |
| 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. | |
| 1447. |
An electron revolves in air in a circle in a plane perpendicular to the principal axis. The air has a uniform magnetic field parallel to the principal axis and of magnitude 2 tesla with centre of circle at a distance 10 cm from the pole of the spherical curved glass \[(\mu =1.5)\] surface of radius of curvature 10 cm as shown in figure. An observer from P sees radius of circle to be 10 mm. The linear momentum of electron is |
| A. | \[0.4\times {{10}^{-21}}kg-m/s\] |
| B. | \[0.8\times {{10}^{-21}}kg-m/s\] |
| C. | \[1.6\times {{10}^{-21}}kg-m/s\] |
| D. | \[2.4\times {{10}^{-21}}kg-m/s\] |
| Answer» D. \[2.4\times {{10}^{-21}}kg-m/s\] | |
| 1448. |
A transparent cylinder has its right half polished so as to act as a mirror. A paraxial light ray is incident from left that is parallel to principal axis, exits parallel to the incident ray as shown. The refractive index n of the material of the cylinder is: |
| A. | 1.2 |
| B. | 1.5 |
| C. | 1.8 |
| D. | 2 |
| Answer» E. | |
| 1449. |
An equiconvex lens has a power of 5 diopter. If it is made of glass of refractive index 1.5 then the radius of the curvature of each surface will be |
| A. | 20 cm |
| B. | 10 cm |
| C. | 5 cm |
| D. | zero |
| Answer» B. 10 cm | |
| 1450. |
Recently, the phenomenon of superconductivity has been observed at 95 K. This temperature is nearly equal to [CPMT 1990] |
| A. | ? 288°F |
| B. | ? 146°F |
| C. | ? 368°F |
| D. | +178°F |
| Answer» B. ? 146°F | |