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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.
| 9701. |
Assertion : The reverberation time dependent on the the shape of enclosure, position of source and observer. Reason : The unit of absorption coefficient in mks system is metric sabine. [EAMCET 2004] |
| 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. | |
| 9702. |
Two waves of lengths 50 cm and 51 cm produced 12 beats per second. The velocity of sound is [CBSE PMT 1999; Pb. PET 2001; AFMC 2003] |
| A. | 306 m/s |
| B. | 331 m/s |
| C. | 340 m/s |
| D. | 360 m/s |
| Answer» B. 331 m/s | |
| 9703. |
R is the radius of the earth and \[\omega \] is its angular velocity and \[{{g}_{p}}\] is the value of g at the poles. The effective value of g at the latitude \[\lambda =60{}^\circ \] will be equal to [MP PMT 1999] |
| A. | \[{{g}_{p}}-\frac{1}{4}R{{\omega }^{2}}\] |
| B. | \[{{g}_{p}}-\frac{3}{4}R{{\omega }^{2}}\] |
| C. | \[{{g}_{p}}-R{{\omega }^{2}}\] |
| D. | \[{{g}_{p}}+\frac{1}{4}R{{\omega }^{2}}\] |
| Answer» B. \[{{g}_{p}}-\frac{3}{4}R{{\omega }^{2}}\] | |
| 9704. |
The potential to which a conductor is raised, depends on [KCET 2005] |
| A. | The amount of charge |
| B. | Geometry and size of the conductor |
| C. | Both (a) and (b) |
| D. | Only on (a) |
| Answer» D. Only on (a) | |
| 9705. |
Which one of the following devices makes use of the electrons to strike certain substances to produce fluorescence [SCRA 1994] |
| A. | Thermionic valve |
| B. | Photoelectric cell |
| C. | Cathode ray oscilloscope |
| D. | Electron gun |
| Answer» D. Electron gun | |
| 9706. |
The de-Broglie wavelength of an electron in the first Bohr orbit is [KCET 2002] |
| A. | Equal to one fourth the circumference of the first orbit |
| B. | Equal to half the circumference of the first orbit |
| C. | Equal to twice the circumference of the first orbit |
| D. | Equal to the circumference of the first orbit |
| Answer» E. | |
| 9707. |
Assertion : A potentiometer of longer length is used for accurate measurement. Reason : The potential gradient for a potentiometer of longer length with a given source of e.m.f. becomes 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. | |
| 9708. |
When the speed of a dc motor increases the armature current [CPMT 1984, 85; MP PMT 2004] |
| A. | Increases |
| B. | Decreases |
| C. | Does not change |
| D. | Increases and decreases continuously |
| Answer» C. Does not change | |
| 9709. |
If vectors P, Q and R have magnitude 5, 12 and 13 units and \[\overrightarrow{P}+\overrightarrow{Q}=\overrightarrow{R},\] the angle between Q and R is [CEET 1998] |
| A. | \[{{\cos }^{-1}}\frac{5}{12}\] |
| B. | \[{{\cos }^{-1}}\frac{5}{13}\] |
| C. | \[{{\cos }^{-1}}\frac{12}{13}\] |
| D. | \[{{\cos }^{-1}}\frac{7}{13}\] |
| Answer» D. \[{{\cos }^{-1}}\frac{7}{13}\] | |
| 9710. |
There are two force vectors, one of 5 N and other of 12 N at what angle the two vectors be added to get resultant vector of 17 N, 7 N and 13 N respectively |
| A. | \[0{}^\circ \], \[\text{18}0{}^\circ \] and \[\text{9}0{}^\circ \] |
| B. | \[0{}^\circ \], \[\text{9}0{}^\circ \] and \[\text{18}0{}^\circ \] |
| C. | \[0{}^\circ \], \[\text{9}0{}^\circ \] and \[\text{9}0{}^\circ \] |
| D. | \[\text{18}0{}^\circ \], \[0{}^\circ \] and \[\text{9}0{}^\circ \] |
| Answer» B. \[0{}^\circ \], \[\text{9}0{}^\circ \] and \[\text{18}0{}^\circ \] | |
| 9711. |
If at same temperature and pressure, the densities for two diatomic gases are respectively \[{{d}_{1}}\] and \[{{d}_{2}}\], then the ratio of velocities of sound in these gases will be [CPMT 2001] |
| A. | \[\sqrt{\frac{{{d}_{2}}}{{{d}_{1}}}}\] |
| B. | \[\sqrt{\frac{{{d}_{1}}}{{{d}_{2}}}}\] |
| C. | \[{{d}_{1}}{{d}_{2}}\] |
| D. | \[\sqrt{{{d}_{1}}{{d}_{2}}}\] |
| Answer» B. \[\sqrt{\frac{{{d}_{1}}}{{{d}_{2}}}}\] | |
| 9712. |
In Searle's method for finding conductivity of metals, the temperature gradient along the bar [MP PMT 1984] |
| A. | Is greater nearer the hot end |
| B. | Is greater nearer to the cold end |
| C. | Is the same at all points along the bar |
| D. | Increases as we go from hot end to cold end |
| Answer» D. Increases as we go from hot end to cold end | |
| 9713. |
It is not possible to write directly on blotting paper or newspaper with ink pen |
| A. | Because of viscosity |
| B. | Because of inertia |
| C. | Because of friction |
| D. | Because of capillarity |
| Answer» E. | |
| 9714. |
Assertion : In series LCR circuit resonance can take place. Reason : Resonance takes place if inductance and capacitive reactances are equal and opposite. [AIIMS 1998] |
| 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. | |
| 9715. |
The direction of magnetic lines of forces close to a straight conductor carrying current will be [RPMT 2002; RPET 2003; MP PET 2003] |
| A. | Along the length of the conductor |
| B. | Radially outward |
| C. | Circular in a plane perpendicular to the conductor |
| D. | Helical |
| Answer» D. Helical | |
| 9716. |
The plates of a parallel plate capacitor of capacity \[50\mu C\] are charged to a potential of \[100\ volts\] and then separated from each other so that the distance between them is doubled. How much is the energy spent in doing so [MP PET 1997; JIPMER 2000] |
| A. | \[25\times {{10}^{-2}}J\] |
| B. | \[-12.5\times {{10}^{-2}}J\] |
| C. | \[-25\times {{10}^{-2}}J\] |
| D. | \[12.5\times {{10}^{-2}}J\] |
| Answer» B. \[-12.5\times {{10}^{-2}}J\] | |
| 9717. |
Assertion : The refractive index of diamond is \[\sqrt{6}\] and that of liquid is \[\sqrt{3}\]. If the light travels from diamond to the liquid, it will totally reflected when the angle of incidence is 30o. Reason : \[\mu =\frac{1}{\sin C},\] where m is the refractive index of diamond with respect to liquid. [AIIMS 2000] |
| 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. | |
| 9718. |
Assertion : A body that is a good radiator is also a good absorber of radiation at a given wavelength. Reason : According to Kirchoff?s law the absorptivity of a body is equal to its emissivity at a given wavelength. [AIIMS 2005] |
| 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. | |
| 9719. |
A solid conducting sphere of radius a has a net positive charge 2Q. A conducting spherical shell of inner radius \[b\] and outer radius c is concentric with the solid sphere and has a net charge ? Q. The surface charge density on the inner and outer surfaces of the spherical shell will be [AMU 2002] |
| A. | \[-\frac{2Q}{4\pi {{b}^{2}}},\frac{Q}{4\pi {{c}^{2}}}\] |
| B. | \[-\frac{Q}{4\pi {{b}^{2}}},\frac{Q}{4\pi {{c}^{2}}}\] |
| C. | \[0,\frac{Q}{4\pi {{c}^{2}}}\] |
| D. | None of the above |
| Answer» B. \[-\frac{Q}{4\pi {{b}^{2}}},\frac{Q}{4\pi {{c}^{2}}}\] | |
| 9720. |
Which of the following is the unit of specific heat [MH CET 2004] |
| A. | \[J\,kg\,{}^\circ {{C}^{-1}}\] |
| B. | \[J/kg\,{}^\circ C\] |
| C. | \[kg\,{}^\circ C/J\] |
| D. | \[J/kg\,{}^\circ {{C}^{-2}}\] |
| Answer» B. \[J/kg\,{}^\circ C\] | |
| 9721. |
Assertion : When a particle moves in a circle with a uniform speed, its velocity and acceleration both changes. Reason : The centripetal acceleration in circular motion is dependent on angular velocity of the body. |
| 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. | |
| 9722. |
Two planets have the same average density but their radii are \[{{R}_{1}}\] and \[{{R}_{2}}\]. If acceleration due to gravity on these planets be \[{{g}_{1}}\] and \[{{g}_{2}}\] respectively, then [AIIMS 1985] |
| A. | \[\frac{{{g}_{1}}}{{{g}_{2}}}=\frac{{{R}_{1}}}{{{R}_{2}}}\] |
| B. | \[\frac{{{g}_{1}}}{{{g}_{2}}}=\frac{{{R}_{2}}}{{{R}_{1}}}\] |
| C. | \[\frac{{{g}_{1}}}{{{g}_{2}}}=\frac{R_{1}^{2}}{R_{2}^{2}}\] |
| D. | \[\frac{{{g}_{1}}}{{{g}_{2}}}=\frac{R_{1}^{3}}{R_{2}^{3}}\] |
| Answer» B. \[\frac{{{g}_{1}}}{{{g}_{2}}}=\frac{{{R}_{2}}}{{{R}_{1}}}\] | |
| 9723. |
A closely wound flat circular coil of 25 turns of wire has diameter of 10 cm and carries a current of 4 ampere. Determine the flux density at the centre of a coil [AIIMS 2001] |
| A. | \[1.679\times {{10}^{-5}}tesla\] |
| B. | \[2.028\times {{10}^{-4}}tesla\] |
| C. | \[1.257\times {{10}^{-3}}tesla\] |
| D. | \[1.512\times {{10}^{-6}}tesla\] |
| Answer» D. \[1.512\times {{10}^{-6}}tesla\] | |
| 9724. |
Consider a compound slab consisting of two different materials having equal thickness and thermal conductivities K and 2K respectively. The equivalent thermal conductivity of the slab is [CBSE PMT 2003] |
| A. | \[\sqrt{2K}\] |
| B. | \[3K\] |
| C. | \[\frac{4}{3}K\] |
| D. | \[\frac{2}{3}K\] |
| Answer» D. \[\frac{2}{3}K\] | |
| 9725. |
Assertion : In photoemissive cell inert gas is used. Reason : Inert gas in the photoemissive cell gives greater current. |
| 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. | |
| 9726. |
Assertion : Diode lasers are used as optical sources in optical communication. Reason : Diode lasers consume less energy. [AIIMS 2005] |
| 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. | |
| 9727. |
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. | |
| 9728. |
A gas is suddenly compressed to 1/4 th of its original volume at normal temperature. The increase in its temperature is \[(\gamma =1.5)\] [DCE 2004] |
| A. | 273 K |
| B. | 573 K |
| C. | 373 K |
| D. | 473 K |
| Answer» B. 573 K | |
| 9729. |
Assertion : Electric appliances with metallic body have three connections, whereas an electric bulb has a two pin connection. Reason : Three pin connections reduce heating of connecting wires. |
| 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. | |
| 9730. |
Four metal conductors having different shapes 1. A sphere 2. Cylindrical 3. Pear 4. Lightning conductor Are mounted on insulating stands and charged. The one which is best suited to retain the charges for a longer time is [KCET 2005] |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» B. 2 | |
| 9731. |
20 ampere current is flowing in a long straight wire. The intensity of magnetic field at a distance 10 cm from the wire will be [Pb. PMT 2003] |
| A. | 4 ´ 10?5 Wb/m2 |
| B. | 9 ´ 10?5 Wb/m2 |
| C. | 8 ´ 10?5 Wb/m2 |
| D. | 6 ´ 10?5 Wb/m2 |
| Answer» B. 9 ´ 10?5 Wb/m2 | |
| 9732. |
Two sound sources when sounded simultaneously produce four beats in 0.25 second. the difference in their frequencies must be [BCECE 2003] |
| A. | 4 |
| B. | 8 |
| C. | 16 |
| D. | 1 |
| Answer» D. 1 | |
| 9733. |
No current flows between two charged bodies connected together when they have the same [MP PMT 1984; CPMT 1971, 83] |
| A. | Capacitance or \[\frac{Q}{V}\] ratio |
| B. | Charge |
| C. | Resistance |
| D. | Potential or \[\frac{Q}{C}\]ratio |
| Answer» E. | |
| 9734. |
Assertion : The slope of displacement-time graph of a body moving with high velocity is steeper than the slope of displacement-time graph of a body with low velocity. Reason : Slope of displacement-time graph = Velocity of the body. |
| 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. | |
| 9735. |
In any Bohr orbit of the hydrogen atom, the ratio of kinetic energy to potential energy of the electron is [MP PET 1994] |
| A. | 1/2 |
| B. | 2 |
| C. | \[-1/2\] |
| D. | ? 2 |
| Answer» D. ? 2 | |
| 9736. |
The following phenomenon cannot be observed for sound waves [NCERT 1982; CPMT 1985, 97; AFMC 2002; RPMT 2003] |
| A. | Refraction |
| B. | Interference |
| C. | Diffraction |
| D. | Polarisation |
| Answer» E. | |
| 9737. |
Assertion : A man sitting in a boat which is floating on a pond. If the man drinks some water from the pond, the level of the water in the pond decreases. Reason : According to Archimede's principle the weight displaced by body is equal to the weight of the body. |
| 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. | |
| 9738. |
Large transformers, when used for some time, become hot and are cooled by circulating oil. The heating of transformer is due to [MP PET 2001] |
| A. | Heating effect of current alone |
| B. | Hysteresis loss alone |
| C. | Both the hysteresis loss and heating effect of current |
| D. | None of the above |
| Answer» D. None of the above | |
| 9739. |
Velocity of sound is maximum in [AFMC 1998; BCECE 2001; RPMT 1999, 02] |
| A. | Air |
| B. | Water |
| C. | Vacuum |
| D. | Steel |
| Answer» E. | |
| 9740. |
Assertion : The ratio of inertial mass to gravitational mass is equal to one. Reason : The inertial mass and gravitational mass of a body are equivalent. |
| 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. | |
| 9741. |
Assertion : A body becomes weightless at the centre of earth. Reason : As the distance from centre of earth decreases, acceleration due to gravity 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. | |
| 9742. |
A bulb is connected first with dc and then ac of same voltage then it will shine brightly with [RPET 2000] |
| A. | AC |
| B. | DC |
| C. | Brightness will be in ratio 1/1.4 |
| D. | Equally with both |
| Answer» E. | |
| 9743. |
An electron beam is moving between two parallel plates having electric field \[1.125\times {{10}^{-6}}N/m\]. A magnetic field \[3\times {{10}^{-10}}T\] is also applied so that beam of electrons do not deflect. The velocity of the electron is [MH CHT 2004] |
| A. | \[4225\ m/s\] |
| B. | \[3750\ m/s\] |
| C. | \[2750\ m/s\] |
| D. | \[3200\ m/s\] |
| Answer» C. \[2750\ m/s\] | |
| 9744. |
Water rises to a height h in a capillary at the surface of earth. On the surface of the moon the height of water column in the same capillary will be [MP PMT 2001] |
| A. | 6h |
| B. | \[\frac{1}{6}h\] |
| C. | h |
| D. | Zero |
| Answer» B. \[\frac{1}{6}h\] | |
| 9745. |
Assertion : The principle of superposition is not valid for gravitational force. Reason : Gravitational force is a conservative force. |
| 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. | |
| 9746. |
Two capillary tubes P and Q are dipped in water. The height of water level in capillary P is 2/3 to the height in Q capillary. The ratio of their diameters is [MP PMT 1985] |
| A. | 2 : 3 |
| B. | 3 : 2 |
| C. | 3 : 4 |
| D. | 4 : 3 |
| Answer» C. 3 : 4 | |
| 9747. |
Two sound waves having a phase difference of 60° have path difference of [CBSE PMT 1996; AIIMS 2001] |
| A. | 2l |
| B. | l/2 |
| C. | l/6 |
| D. | l/3 |
| Answer» D. l/3 | |
| 9748. |
If m1 and m2 are the refractive indices of the materials of core and cladding of an optical fibre, then the loss of light due to its leakage can be minimised by having [BVP 2003] |
| A. | m1 > m2 |
| B. | m1 < m2 |
| C. | m1 = m2 |
| D. | None of these |
| Answer» B. m1 < m2 | |
| 9749. |
An object of m kg with speed of v m/s strikes a wall at an angle q and rebounds at the same speed and same angle. The magnitude of the change in momentum of the object will be |
| A. | \[2m\,v\,\cos \theta \] |
| B. | \[2\,m\,v\,\sin \theta \] |
| C. | 0 |
| D. | \[2\,m\,v\] |
| Answer» B. \[2\,m\,v\,\sin \theta \] | |
| 9750. |
Assertion : Semiconductors do not Obey's Ohm's law. Reason : Current is determined by the rate of flow of charge carriers. |
| 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. | |