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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.
| 1551. |
An aircraft is moving with a velocity of \[300\,m{{s}^{-1}}.\] If all the forces acting on it are balanced, then [Kerala PMT 2004] |
| A. | It still moves with the same velocity |
| B. | It will be just floating at the same point in space |
| C. | It will fall down instantaneously |
| D. | It will lose its velocity gradually |
| E. | It will explode |
| Answer» B. It will be just floating at the same point in space | |
| 1552. |
A particle of mass \[{{m}_{1}}\] is moving with a velocity \[{{v}_{1}}\]and another particle of mass \[{{m}_{2}}\]is moving with a velocity \[{{v}_{2}}\]. Both of them have the same momentum but their different kinetic energies are \[{{E}_{1}}\]and \[{{E}_{2}}\]respectively. If \[{{m}_{1}}>{{m}_{2}}\] then [CBSE PMT 2004] |
| A. | \[{{E}_{1}}<{{E}_{2}}\] |
| B. | \[\frac{{{E}_{1}}}{{{E}_{2}}}=\frac{{{m}_{1}}}{{{m}_{2}}}\] |
| C. | \[{{E}_{1}}>{{E}_{2}}\] |
| D. | \[{{E}_{1}}={{E}_{2}}\] |
| Answer» B. \[\frac{{{E}_{1}}}{{{E}_{2}}}=\frac{{{m}_{1}}}{{{m}_{2}}}\] | |
| 1553. |
If a particle moves in a circle describing equal angles in equal times, its velocity vector [CPMT 1972, 74; JIPMER 1997] |
| A. | Remains constant |
| B. | Changes in magnitude |
| C. | Changes in direction |
| D. | Changes both in magnitude and direction |
| Answer» D. Changes both in magnitude and direction | |
| 1554. |
Orbital acceleration of electron is |
| A. | \[\frac{{{n}^{2}}{{h}^{2}}}{4{{\pi }^{2}}{{m}^{2}}{{r}^{3}}}\] |
| B. | \[\frac{{{n}^{2}}{{h}^{2}}}{2{{n}^{2}}{{r}^{3}}}\] |
| C. | \[\frac{4{{n}^{2}}{{h}^{2}}}{{{\pi }^{2}}{{m}^{2}}{{r}^{3}}}\] |
| D. | \[\frac{4{{n}^{2}}{{h}^{2}}}{4{{\pi }^{2}}{{m}^{2}}{{r}^{3}}}\] |
| Answer» B. \[\frac{{{n}^{2}}{{h}^{2}}}{2{{n}^{2}}{{r}^{3}}}\] | |
| 1555. |
The wavelength of light emitted from second orbit to first orbits in a hydrogen atom is |
| A. | \[1.215\times {{10}^{-7}}m\] |
| B. | \[1.215\times {{10}^{-5}}m\] |
| C. | \[1.215\times {{10}^{-4}}m\] |
| D. | \[1.215\times {{10}^{-3}}m\] |
| Answer» B. \[1.215\times {{10}^{-5}}m\] | |
| 1556. |
The possible quantum number for 3d electron are |
| A. | \[n=3,\,l=1,\,{{m}_{l}}=+1,\,{{m}_{s}}=-\frac{1}{2}\] |
| B. | \[n=3,\,l=2,\,{{m}_{l}}=+2,\,{{m}_{s}}=-\frac{1}{2}\] |
| C. | \[n=3,\,l=1,\,{{m}_{l}}=-1,\,{{m}_{s}}=+\frac{1}{2}\] |
| D. | \[n=3,\,l=0,\,{{m}_{l}}=+1,\,{{m}_{s}}=-\frac{1}{2}\] |
| Answer» C. \[n=3,\,l=1,\,{{m}_{l}}=-1,\,{{m}_{s}}=+\frac{1}{2}\] | |
| 1557. |
A generator produces a voltage that is given by \[V=240\sin 120\,t\], where t is in seconds. The frequency and r.m.s. voltage are [MP PET 1993; MP PMT 1990] |
| A. | 60 Hz and 240 V |
| B. | 19 Hz and 120 V |
| C. | 19 Hz and 170 V |
| D. | 754 Hz and 70 V |
| Answer» D. 754 Hz and 70 V | |
| 1558. |
One end of a uniform rod of length 1 m is placed in boiling water while its other end is placed in melting ice. A point P on the rod is maintained at a constant temperature of \[800{}^\circ C\]. The mass of steam produced per second is equal to the mass of ice melted per second. If specific latent heat of steam is 7 times the specific latent heat of ice, the distance of P from the steam chamber must be |
| A. | (1/7) m |
| B. | (1/8) m |
| C. | (1/9) m |
| D. | (1/10) m |
| Answer» D. (1/10) m | |
| 1559. |
Core of transformer is made up of [AFMC 2005] |
| A. | Soft iron |
| B. | Steel |
| C. | Iron |
| D. | Alnico |
| Answer» B. Steel | |
| 1560. |
The ratio of Young's modulus of the material of two wires is 2 : 3. If the same stress is applied on both, then the ratio of elastic energy per unit volume will be |
| A. | 3 : 2 |
| B. | 2 : 3 |
| C. | 3 : 4 |
| D. | 4 : 3 |
| Answer» B. 2 : 3 | |
| 1561. |
Pure \[Si\] at \[500K\] has equal number of electron \[({{n}_{e}})\] and hole \[({{n}_{h}})\] concentrations of \[1.5\times {{10}^{16}}{{m}^{-3}}.\] Doping by indium increases \[{{n}_{h}}\] to \[4.5\times {{10}^{22}}{{m}^{-3}}.\] The doped semiconductor is of |
| A. | n-type with electron concentration \[{{n}_{e}}=5\times {{10}^{22}}{{m}^{-3}}\] |
| B. | p-type with electron concentration \[{{n}_{e}}=2.5\times {{10}^{10}}{{m}^{-3}}\] |
| C. | n-type with electron concentration \[{{n}_{e}}=2.5\times {{10}^{23}}{{m}^{-3}}\] |
| D. | p-type having electron concentration \[{{n}_{e}}=5\times {{10}^{9}}{{m}^{-3}}\] |
| Answer» E. | |
| 1562. |
A body floats in a liquid contained in a beaker. If the whole system as shown in figure falls freely under gravity, then the upthrust on the body due to liquid is [Manipal MEE 1995] |
| A. | Zero |
| B. | Equal to the weight of liquid displaced |
| C. | Equal to the weight of the body in air |
| D. | None of these |
| Answer» B. Equal to the weight of liquid displaced | |
| 1563. |
Assertion : In meter bridge experiment, a high resistance is always connected in series with a galvanometer. Reason : As resistance increases current through the circuit increases. |
| 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» D. If the assertion and reason both are false. | |
| 1564. |
A rocket can go vertically upwards in earth's atmosphere because [CPMT 1980] |
| A. | It is lighter than air |
| B. | Of gravitational pull of the sun |
| C. | It has a fan which displaces more air per unit time than the weight of the rocket |
| D. | Of the force exerted on the rocket by gases ejected by it |
| Answer» E. | |
| 1565. |
Assertion : A man would feel iron or wooden balls equally hot at 98.4°F. Reason : At 98.4°F both iron and wood have same thermal conductivity. |
| 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» D. If the assertion and reason both are false. | |
| 1566. |
A black body of surface area \[10\,c{{m}^{2}}\] is heated to \[127{}^\circ C\] and is suspended in a room at temperature \[27{}^\circ C\]. The initial rate of loss of heat from the body at the room temperature will be |
| A. | 2.99 W |
| B. | 1.89 W |
| C. | 1.18 W |
| D. | 0.99 W |
| Answer» E. | |
| 1567. |
Two black metallic spheres of radius 4m, at 2000 K and 1m at 4000 K will have ratio of energy radiation as |
| A. | 0.0423611111111111 |
| B. | 0.167361111111111 |
| C. | 0.0444444444444444 |
| D. | 0.0840277777777778 |
| Answer» B. 0.167361111111111 | |
| 1568. |
The coil of choke in a circuit [AIIMS 2001] |
| A. | Increases the current |
| B. | Decreases the current |
| C. | Does not change the current |
| D. | Has high resistance to dc circuit |
| Answer» C. Does not change the current | |
| 1569. |
A thick-walled hollow sphere has outside radius\[{{R}_{0}}\]. It rolls down an incline without slipping and its speed at the bottom is\[{{v}_{0}}\]. Now the incline is waxed, so that it is practically frictionless and the sphere is observed to slide down (without any rolling). Its speed at the bottom is observed to be\[5{{v}_{0}}/4\]. The radius of gyration of the hollow sphere about an axis through its centre is |
| A. | \[3{{R}_{0}}/2\] |
| B. | \[3{{R}_{0}}/4\] |
| C. | \[9{{R}_{0}}/16\] |
| D. | \[3{{R}_{0}}\] |
| Answer» C. \[9{{R}_{0}}/16\] | |
| 1570. |
Radius of a soap bubble is increased from R to 2R work done in this process in terms of surface tension is [BHU 2003, RPET 2001; CPMT 2004] |
| A. | \[24\pi {{R}^{2}}S\] |
| B. | \[48\pi {{R}^{2}}S\] |
| C. | \[12\pi {{R}^{2}}S\] |
| D. | \[36\pi {{R}^{2}}S\] |
| Answer» B. \[48\pi {{R}^{2}}S\] | |
| 1571. |
In a Young's double slit experiment, the two slits act as coherent sources of wave of equal amplitude A and wavelength X. In another experiment with the same arrangement the two slits are made to act as incoherent sources of waves of same amplitude and wavelength. If the intensity at the middle point of the screen in the first case is\[{{I}_{1}}\]and in the second case is\[{{I}_{2}}\], then the ratio\[\frac{{{I}_{1}}}{{{I}_{2}}}\]is |
| A. | 2 |
| B. | 1 |
| C. | 0.5 |
| D. | 4 |
| Answer» B. 1 | |
| 1572. |
If a body looses half of its velocity on penetrating 3 cm in a wooden block, then how much will it penetrate more before coming to rest [AIEEE 2002; DCE 2002] |
| A. | 1 cm |
| B. | 2 cm |
| C. | 3 cm |
| D. | 4 cm |
| Answer» B. 2 cm | |
| 1573. |
When a tuning fork vibrates, the waves produced in the fork are [AFMC 2001] |
| A. | Longitudinal |
| B. | Transverse |
| C. | Progressive |
| D. | Stationary |
| Answer» B. Transverse | |
| 1574. |
Two vibrating tuning forks produce progressive waves given by \[{{Y}_{1}}=4\sin 500\pi t\]and \[{{Y}_{2}}=2\sin 506\pi t.\] Number of beats produced per minute is [CBSE PMT 2005] |
| A. | 360 |
| B. | 180 |
| C. | 3 |
| D. | 60 |
| Answer» C. 3 | |
| 1575. |
A rubber pipe of density \[1.5\times {{10}^{3}}\,N/{{m}^{2}}\] and Young's modulus \[5\times {{10}^{6}}\,N/{{m}^{2}}\] is suspended from the roof. The length of the pipe is 8 m. What will be the change in length due to its own weight [RPET 1996] |
| A. | 9.6 m |
| B. | \[9.6\times {{10}^{3}}\,m\] |
| C. | \[19.2\times {{10}^{-2}}\,m\] |
| D. | \[9.6\times {{10}^{-2}}\,m\] |
| Answer» E. | |
| 1576. |
The frequency of tuning forks A and B are respectively 3% more and 2% less than the frequency of tuning fork C. When A and B are simultaneously excited, 5 beats per second are produced. Then the frequency of the tuning fork 'A' (in Hz) is [EAMCET 2001] |
| A. | 98 |
| B. | 100 |
| C. | 103 |
| D. | 105 |
| Answer» D. 105 | |
| 1577. |
Assertion : The electromagnetic waves of shorter wavelength can travel longer distances on earth's surface than those of longer wavelengths. Reason : Shorter the wavelength, the larger is the velocity of wave propagation. |
| 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» D. If the assertion and reason both are false. | |
| 1578. |
In the circuit given below, the value of the current is |
| A. | 0 amp |
| B. | \[{{10}^{-2}}\] amp |
| C. | \[{{10}^{2}}\]amp |
| D. | \[{{10}^{-3}}\]amp |
| Answer» C. \[{{10}^{2}}\]amp | |
| 1579. |
The height of liquid column in a U tube is 0.3 m. If the liquid in one of the limbs is depressed and then released, then the time period of the liquid column will be |
| A. | 1.1 sec |
| B. | 19 sec |
| C. | 0.11 sec |
| D. | 2 sec |
| Answer» B. 19 sec | |
| 1580. |
Identify the wrong statement in the following. Coulomb's law correctly describes the electric force that [KCET 2005] |
| A. | Binds the electrons of an atom to its nucleus |
| B. | Binds the protons and neutrons in the nucleus of an atom |
| C. | Binds atoms together to form molecules |
| D. | Binds atoms and molecules together to form solids |
| Answer» C. Binds atoms together to form molecules | |
| 1581. |
If a load of 9 kg is suspended on a wire, the increase in length is 4.5 mm. The force constant of the wire is |
| A. | \[0.49\times {{10}^{4}}\,N/m\] |
| B. | \[1.96\times {{10}^{4}}\,N/m\] |
| C. | \[4.9\times {{10}^{4}}\,N/m\] |
| D. | \[0.196\times {{10}^{4}}\,N/m\] |
| Answer» C. \[4.9\times {{10}^{4}}\,N/m\] | |
| 1582. |
In YDSE a light containing two wavelengths 500 nm and 700 nm are used. Find the minimum distance where maxima of two wavelengths coincide. Given \[D/d={{10}^{3}}\], where D is the distance between the slits and the screen and d is the distance between the slits. |
| A. | 1.2 m |
| B. | 3.5 mm |
| C. | 2.8 cm |
| D. | 8.1 mm |
| Answer» C. 2.8 cm | |
| 1583. |
One Tesla is equal to [AFMC 1998] |
| A. | \[{{10}^{7}}\,gauss\] |
| B. | \[{{10}^{-4}}\,gauss\] |
| C. | \[{{10}^{4}}\,gauss\] |
| D. | \[{{10}^{-8}}\,gauss\] |
| Answer» D. \[{{10}^{-8}}\,gauss\] | |
| 1584. |
Assertion : Only microwaves are used in radar. Reason : Because microwaves have very small wavelength. |
| 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. | |
| 1585. |
Assertion : In Hertz experiment, the electric vector of radiation produced by the source gap is parallel to the gap. Reason : Production of sparks between the detector gap is maximum when it is placed perpendicular to the source gap. |
| 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» D. If the assertion and reason both are false. | |
| 1586. |
Assertion : The electrical conductivity of earth?s atmosphere decrease with altitude. Reason : The high energy particles (i.e. g-rays and cosmic rays) coming from outer space and entering our earth?s atmosphere causes ionisation of the atoms of the gases present there and the pressure of gases decreases with increase in altitude. |
| 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. | |
| 1587. |
A wooden stick 2m long is floating on the surface of water. The surface tension of water 0.07 N/m. By putting soap solution on one side of the sticks the surface tension is reduced to 0.06 N/m. The net force on the stick will be [Pb. PMT 2002] |
| A. | 0.07 N |
| B. | 0.06 N |
| C. | 0.01 N |
| D. | 0.02 N |
| Answer» E. | |
| 1588. |
Mark the wrong statement [MP PMT 2003] |
| A. | All S.H.M.?s have fixed time period |
| B. | All motion having same time period are S.H.M. |
| C. | In S.H.M. total energy is proportional to square of amplitude |
| D. | Phase constant of S.H.M. depends upon initial conditions |
| Answer» C. In S.H.M. total energy is proportional to square of amplitude | |
| 1589. |
A particle in SHM is described by the displacement equation \[x(t)=A\cos (\omega t+\theta ).\]If the initial (t = 0) position of the particle is 1 cm and its initial velocity is \[\pi \]cm/s, what is its amplitude? The angular frequency of the particle is \[\pi {{s}^{-1}}\] [DPMT 2004] |
| A. | 1 cm |
| B. | \[\sqrt{2}\]cm |
| C. | 2 cm |
| D. | 2.5 cm |
| Answer» C. 2 cm | |
| 1590. |
A particle executes SHM in a line 4 cm long. Its velocity when passing through the centre of line is 12 cm/s. The period will be [Pb. PET 2000] |
| A. | 2.047 s |
| B. | 1.047 s |
| C. | 3.047 s |
| D. | 0.047 s |
| Answer» C. 3.047 s | |
| 1591. |
In an ore containing uranium, the ratio of \[{{U}^{238}}\] to \[P{{b}^{206}}\]nuclei is 3. Calculate the age of the ore, assuming that all the lead present in the ore in the final stable product of \[{{U}^{238}}\]. Take the half-life of \[{{U}^{238}}\]to be \[4.5\times {{10}^{9}}\]ear. |
| A. | \[1.8\times {{10}^{9}}\] year |
| B. | \[2.3\times {{10}^{10}}\]year |
| C. | \[5.1\times {{10}^{7}}\] year |
| D. | \[6.2\times {{10}^{6}}\]year |
| Answer» B. \[2.3\times {{10}^{10}}\]year | |
| 1592. |
The electron in a hydrogen atom makes a transition\[{{n}_{1}}\to {{n}_{2}}\], where \[{{n}_{1}}\] and \[{{n}_{2}}\] are the principal quantum numbers of the two states. Assume the Bohr model to be valid. The time period of the electron in the initial state is eight times that in the final state. The possible values of n1 and n2 are [IIT 1998; KCET 2005] |
| A. | \[{{n}_{1}}=4,\ {{n}_{2}}=2\] |
| B. | \[{{n}_{1}}=8,\ {{n}_{2}}=2\] |
| C. | \[{{n}_{1}}=8,\ {{n}_{2}}=1\] |
| D. | \[{{n}_{1}}=6,\ {{n}_{2}}=3\] |
| Answer» E. | |
| 1593. |
Assertion : If \[|\vec{A}+\vec{B}|\ =\ |\vec{A}-\vec{B}|\], then angle between \[\vec{A}\] and \[\vec{B}\] is 90° Reason : \[\vec{A}+\vec{B}\ =\ \vec{B}+\vec{A}\] |
| 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. | |
| 1594. |
When a 1.0kg mass hangs attached to a spring of length 50 cm, the spring stretches by 2 cm. The mass is pulled down until the length of the spring becomes 60 cm. What is the amount of elastic energy stored in the spring in this condition, if g = 10 m/s2 [MP PET 2001] |
| A. | 1.5 Joule |
| B. | 2.0 Joule |
| C. | 2.5 Joule |
| D. | 3.0 Joule |
| Answer» D. 3.0 Joule | |
| 1595. |
A radioactive element decays by p emission. A detector records n beta particles in 2 second and in next 2 seconds it records \[0.75\text{ }n\] beta particles. Find mean life corrected to nearest whole number. Given \[\ell n2=0.6931\] and \[\ell n3=1.0986.\]. |
| A. | \[6.9\text{ }sec\] |
| B. | \[9.9\text{ }sec\] |
| C. | \[10.1\text{ }sec\] |
| D. | \[12.2\text{ }sec\] |
| Answer» B. \[9.9\text{ }sec\] | |
| 1596. |
At zero Kelvin a piece of germanium [MP PET 1999] |
| A. | Becomes semiconductor |
| B. | Becomes good conductor |
| C. | Becomes bad conductor |
| D. | Has maximum conductivity |
| Answer» D. Has maximum conductivity | |
| 1597. |
Hydrogen atoms are excited from ground state of the principal quantum number 4. Then the number of spectral lines observed will be [CBSE PMT 1993] |
| A. | 3 |
| B. | 6 |
| C. | 5 |
| D. | 2 |
| Answer» C. 5 | |
| 1598. |
A N-type semiconductor is [AFMC 1988; RPMT 1999] |
| A. | Negatively charged |
| B. | Positively charged |
| C. | Neutral |
| D. | None of these |
| Answer» D. None of these | |
| 1599. |
The ratio of minimum to maximum wavelength in Balmer series is [MP PET 2000] |
| A. | 5 : 9 |
| B. | 5 : 36 |
| C. | 1 : 4 |
| D. | 3 : 4 |
| Answer» B. 5 : 36 | |
| 1600. |
In an A.C. circuit the current [CPMT 2005] |
| A. | Always leads the voltage |
| B. | Always lags behind the voltage |
| C. | Is always in phase with the voltage |
| D. | May lead or lag behind or be in phase with the voltage |
| Answer» E. | |