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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.
| 8051. |
A person runs with a speed u towards a bicycle moving away from him with speed v. The person approaches his image in the mirror fixed at the rear of bicycle with a speed of |
| A. | u ? v |
| B. | u ? 2v |
| C. | 2u ? v |
| D. | 2(u ? v) |
| Answer» E. | |
| 8052. |
Consider the situation shown in figure. Water \[\left( {{\mu }_{w}}=\frac{4}{3} \right)\] is filled in a breaker upto a height of 10 cm. A plane mirror fixed at a height of 5 cm from the surface of water. Distance of image from the mirror after reflection from it of an object O at the bottom of the beaker is |
| A. | 15 cm |
| B. | 12.5 cm |
| C. | 7.5 cm |
| D. | 10 cm |
| Answer» C. 7.5 cm | |
| 8053. |
One side of a glass slab is silvered as shown. A ray of light is incident on the other side at angle of incidence \[i={{45}^{o}}\]. Refractive index of glass is given as 1.5. The deviation of the ray of light from its initial path when it comes out of the slab is |
| A. | 90o |
| B. | 180o |
| C. | 120o |
| D. | 45o |
| Answer» B. 180o | |
| 8054. |
An atomic power nuclear reactor can deliver 300 MW. The energy released due to fission of each nucleus of uranium atom \[{{U}^{238}}\] is 170 MeV. The number of uranium atoms fissioned per hour will be [Pb. PET 2004; Kerala PET 2005] |
| A. | \[30\times {{10}^{25}}\] |
| B. | \[4\times {{10}^{22}}\] |
| C. | \[10\times {{10}^{20}}\] |
| D. | \[5\times {{10}^{15}}\] |
| Answer» C. \[10\times {{10}^{20}}\] | |
| 8055. |
A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10 divisions per milliampere and voltage sensitivity is 2 divisions per millivolt. In order that each division reads 1 volt, the resistance in ohms needed to be connected in series with the coil will be [AIEEE 2005] |
| A. | 99995 |
| B. | 9995 |
| C. | \[{{10}^{3}}\] |
| D. | \[{{10}^{5}}\] |
| Answer» C. \[{{10}^{3}}\] | |
| 8056. |
Condenser \[A\] has a capacity of \[15\mu F\] when it is filled with a medium of dielectric constant 15. Another condenser \[B\] has a capacity of \[1\mu F\]with air between the plates. Both are charged separately by a battery of\[100\ V\]. After charging, both are connected in parallel without the battery and the dielectric medium being removed. The common potential now is [MNR 1994] |
| A. | \[400V\] |
| B. | \[800\ V\] |
| C. | \[1200\ V\] |
| D. | \[1600\ V\] |
| Answer» C. \[1200\ V\] | |
| 8057. |
A 20 cm length of a certain solution causes right-handed rotation of 38°. A 30cm length of another solution causes left-handed rotation of 24°. The optical rotation caused by 30cm length of a mixture of the above solutions in the volume ratio 1 : 2 is [KCET 2001] |
| A. | Left handed rotation of 14° |
| B. | Right handed rotation of 14° |
| C. | Left handed rotation of 3° |
| D. | Right handed rotation of 3° |
| Answer» E. | |
| 8058. |
The rate of disintegration was observed to be \[{{10}^{17}}\] disintegrations per sec when its half life period is 1445 years. The original number of particles are [Pb. PET 2001] |
| A. | \[8.9\times {{10}^{27}}\] |
| B. | \[6.6\times {{10}^{27}}\] |
| C. | \[1.4\times {{10}^{16}}\] |
| D. | \[1.2\times {{10}^{17}}\] |
| Answer» C. \[1.4\times {{10}^{16}}\] | |
| 8059. |
The resistance of the series combination of two resistance is S. When they are joined in parallel the total resistance is P. If S = nP, then the minimum possible value of n is [AIEEE 2004] |
| A. | 4 |
| B. | 3 |
| C. | 2 |
| D. | 1 |
| Answer» B. 3 | |
| 8060. |
A parallel plate capacitor of capacitance C is connected to a battery and is charged to a potential difference V. Another capacitor of capacitance 2C is connected to another battery and is charged to potential difference 2V. The charging batteries are now disconnected and the capacitors are connected in parallel to each other in such a way that the positive terminal of one is connected to the negative terminal of the other. The final energy of the configuration is [IIT 1995] |
| A. | Zero |
| B. | \[\frac{25C{{V}^{2}}}{6}\] |
| C. | \[\frac{3C{{V}^{2}}}{2}\] |
| D. | \[\frac{9C{{V}^{2}}}{2}\] |
| Answer» D. \[\frac{9C{{V}^{2}}}{2}\] | |
| 8061. |
Specific rotation of sugar solution is 0.01 SI units. 200\[kg{{m}^{-3}}\]of impure sugar solution is taken in a polarimeter tube of length 0.25m and an optical rotation of 0.4rad is observed. The percentage of purity of sugar is the sample is [KCET 2004] |
| A. | 80% |
| B. | 89% |
| C. | 11% |
| D. | 20% |
| Answer» B. 89% | |
| 8062. |
A plane mirror is placed at the bottom of the tank containing a liquid of refractive index \[\mu \]. P is a small object at a height h above the mirror. An observer O-vertically above P outside the liquid see P and its image in the mirror. The apparent distance between these two will be |
| A. | \[2\mu h\] |
| B. | \[\frac{2h}{\mu }\] |
| C. | \[\frac{2h}{\mu -1}\] |
| D. | \[h\,\left( 1+\frac{1}{\mu } \right)\] |
| Answer» C. \[\frac{2h}{\mu -1}\] | |
| 8063. |
Excitation energy of a hydrogen like ion in its first excitation state is 40.8 eV. Energy needed to remove the electron from the ion in ground state is [KCET 2004] |
| A. | 54.4 eV |
| B. | 13.6 eV |
| C. | 40.8 eV |
| D. | 27.2 eV |
| Answer» B. 13.6 eV | |
| 8064. |
The reading of the ideal voltmeter in the adjoining diagram will be |
| A. | 4 V |
| B. | 8 V |
| C. | 12 V |
| D. | 14 V |
| Answer» C. 12 V | |
| 8065. |
Figure given below shows two identical parallel plate capacitors connected to a battery with switch \[S\]closed. The switch is now opened and the free space between the plate of capacitors is filled with a dielectric of dielectric constant 3. What will be the ratio of total electrostatic energy stored in both capacitors before and after the introduction of the dielectric [IIT 1983] |
| A. | 3 : 1 |
| B. | 5 : 1 |
| C. | 3 : 5 |
| D. | 5 : 3 |
| Answer» D. 5 : 3 | |
| 8066. |
If an object moves towards a plane mirror with a speed v at an angle \[\theta \] to the perpendicular to the plane of the mirror, find the relative velocity between the object and the image |
| A. | v |
| B. | 2v |
| C. | \[2v\cos \theta \] |
| D. | \[2v\sin \theta \] |
| Answer» D. \[2v\sin \theta \] | |
| 8067. |
After 280 days, the activity of a radioactive sample is 6000 dps. The activity reduces to 3000 dps after another 140 days. The initial activity of the sample in dps is [IIT-JEE (Screening) 2004] |
| A. | 6000 |
| B. | 9000 |
| C. | 3000 |
| D. | 24000 |
| Answer» E. | |
| 8068. |
In the figure below, what is the potential difference between the point A and B and between B and C respectively in steady state [IIT 1979] |
| A. | \[{{V}_{AB}}={{V}_{BC}}=100\,V\] |
| B. | \[{{V}_{AB}}=75\,V,\ {{V}_{BC}}=25\ V\] |
| C. | \[{{V}_{AB}}=25\,V,\ {{V}_{BC}}=75\ V\] |
| D. | \[{{V}_{AB}}={{V}_{BC}}=50\ V\] |
| Answer» D. \[{{V}_{AB}}={{V}_{BC}}=50\ V\] | |
| 8069. |
Figure shows a cubical room ABCD with the wall CD as a plane mirror. Each side of the room is 3m. We place a camera at the midpoint of the wall AB. At what distance should the camera be focussed to photograph an object placed at A |
| A. | 1.5 m |
| B. | 3 m |
| C. | 6 m |
| D. | More than 6 m |
| Answer» E. | |
| 8070. |
The voltage gain of the following amplifier is [AIIMS 2005] |
| A. | 10 |
| B. | 100 |
| C. | 1000 |
| D. | 9.9 |
| Answer» C. 1000 | |
| 8071. |
Half life of a radio-active substance is 20 minutes. The time between 20% and 80% decay will be [KCET 2003] |
| A. | 20 minutes |
| B. | 40 minutes |
| C. | 30 minutes |
| D. | 25 minutes |
| Answer» C. 30 minutes | |
| 8072. |
An earthquake generates both transverse (S) and longitudinal (P) sound waves in the earth. The speed of S waves is about 4.5 km/s and that of P waves is about 8.0 km/s. A seismograph records P and S waves from an earthquake. The first P wave arrives 4.0 min before the first S wave. The epicenter of the earthquake is located at a distance about [AIIMS 2003] |
| A. | 25 km |
| B. | 250 km |
| C. | 2500 km |
| D. | 5000 km |
| Answer» D. 5000 km | |
| 8073. |
In the adjoining circuit diagram each resistance is of 10 W. The current in the arm AD will be |
| A. | \[\frac{2i}{5}\] |
| B. | \[\frac{3i}{5}\] |
| C. | \[\frac{4i}{5}\] |
| D. | \[\frac{i}{5}\] |
| Answer» B. \[\frac{3i}{5}\] | |
| 8074. |
Two condensers of capacities \[2C\] and C are joined in parallel and charged upto potential V. The battery is removed and the condenser of capacity C is filled completely with a medium of dielectric constant K. The p.d. across the capacitors will now be [IIT 1988] |
| A. | \[\frac{3V}{K+2}\] |
| B. | \[\frac{3V}{K}\] |
| C. | \[\frac{V}{K+2}\] |
| D. | \[\frac{V}{K}\] |
| Answer» B. \[\frac{3V}{K}\] | |
| 8075. |
One end of a uniform wire of length L and of weight W is attached rigidly to a point in the roof and a weight \[{{W}_{1}}\] is suspended from its lower end. If S is the area of cross-section of the wire, the stress in the wire at a height 3L/4 from its lower end is [IIT 1992] |
| A. | \[\frac{{{W}_{1}}}{S}\] |
| B. | \[\frac{{{W}_{1}}+(W/4)}{S}\] |
| C. | \[\frac{{{W}_{1}}+(3W/4)}{S}\] |
| D. | \[\frac{{{W}_{1}}+W}{S}\] |
| Answer» D. \[\frac{{{W}_{1}}+W}{S}\] | |
| 8076. |
Suppose the gravitational force varies inversely as the \[{{n}^{th}}\] power of distance. Then the time period of a planet in circular orbit of radius R around the sun will be proportional to [AIEEE 2004] |
| A. | \[{{R}^{\left( \frac{n+1}{2} \right)}}\] |
| B. | \[{{R}^{\left( \frac{n-1}{2} \right)}}\] |
| C. | \[{{R}^{n}}\] |
| D. | \[{{R}^{\left( \frac{n-2}{2} \right)}}\] |
| Answer» B. \[{{R}^{\left( \frac{n-1}{2} \right)}}\] | |
| 8077. |
The displacement x of a particle moving in one dimension under the action of a constant force is related to the time t by the equation \[t=\sqrt{x}+3\], where x is in meters and t is in seconds. The work done by the force in the first 6 seconds is [IIT 1979] |
| A. | 9 J |
| B. | 6 J |
| C. | 0 J |
| D. | 3 J |
| Answer» D. 3 J | |
| 8078. |
A particle of mass \[m\] is moving in a circular path of constant radius \[r\] such that its centripetal acceleration \[{{a}_{c}}\] is varying with time t as, \[{{a}_{c}}={{k}^{2}}r{{t}^{2}}\], The power delivered to the particle by the forces acting on it is [IIT 1994] |
| A. | \[2\pi m{{k}^{2}}{{r}^{2}}t\] |
| B. | \[m{{k}^{2}}{{r}^{2}}t\] |
| C. | \[\frac{m{{k}^{4}}{{r}^{2}}{{t}^{5}}}{3}\] |
| D. | Zero |
| Answer» C. \[\frac{m{{k}^{4}}{{r}^{2}}{{t}^{5}}}{3}\] | |
| 8079. |
If the dimensions of length are expressed as \[{{G}^{x}}{{c}^{y}}{{h}^{z}}\]; where \[G,\,c\] and \[h\] are the universal gravitational constant, speed of light and Planck's constant respectively, then [IIT 1992] |
| A. | \[x=\frac{1}{2},\,\,y=\frac{1}{2}\] |
| B. | \[x=\frac{1}{2},\,\,z=\frac{1}{2}\] |
| C. | \[y=\frac{1}{2},\,\,z=\frac{3}{2}\] |
| D. | \[y=-\frac{3}{2},\,\,z=\frac{1}{2}\] |
| Answer» C. \[y=\frac{1}{2},\,\,z=\frac{3}{2}\] | |
| 8080. |
In Young's double slit experiment, white light is used. The separation between the slits is b. The screen is at a distance d (d>> b) from the slits. Some wavelengths are missing exactly in front of one slit. These wavelengths are [IIT 1984; AIIMS 1995] |
| A. | \[\lambda =\frac{{{b}^{2}}}{d}\] |
| B. | \[\lambda =\frac{2{{b}^{2}}}{d}\] |
| C. | \[\lambda =\frac{{{b}^{2}}}{3d}\] |
| D. | \[\lambda =\frac{2{{b}^{2}}}{3d}\] |
| Answer» B. \[\lambda =\frac{2{{b}^{2}}}{d}\] | |
| 8081. |
A thin rod of length\[f/3\] lies along the axis of a concave mirror of focal length \[f.\] One end of its magnified image touches an end of the rod. The length of the image is [MP PET 1995] |
| A. | \[f\] |
| B. | \[\frac{1}{2}f\] |
| C. | \[2f\] |
| D. | \[\frac{1}{4}f\] |
| Answer» C. \[2f\] | |
| 8082. |
When a potential difference is applied across, the current passing through [IIT-JEE 1999] |
| A. | An insulator at \[0K\] is zero |
| B. | A semiconductor at \[0K\] is zero |
| C. | A metal at \[0K\] is finite |
| D. | A P-N diode at \[300K\] is finite, if it is reverse biased |
| Answer» C. A metal at \[0K\] is finite | |
| 8083. |
A transmitter supplies 9 kW to the aerial when unmodulated. The power radiated when modulated to 40% is |
| A. | 5 kW |
| B. | 9.72 kW |
| C. | 10 kW |
| D. | 12 kW |
| Answer» C. 10 kW | |
| 8084. |
An energy of 24.6 eV is required to remove one of the electrons from a neutral helium atom. The energy (in eV) required to remove both the electrons from a neutral helium atom is [IIT 1995] |
| A. | 79.0 |
| B. | 51.8 |
| C. | 49.2 |
| D. | 38.2 |
| Answer» B. 51.8 | |
| 8085. |
An image of the sun is formed by a lens of focal length of 30 cm on the metal surface of a photoelectric cell and a photoelectric current I is produced. The lens forming the image is then replaced by another of the same diameter but of focal length 15 cm. The photoelectric current in this case is [Manipal MEE 1995] |
| A. | \[\frac{I}{2}\] |
| B. | I |
| C. | 2I |
| D. | 4I |
| Answer» E. | |
| 8086. |
Two conducting circular loops of radii \[{{R}_{1}}\] and \[{{R}_{2}}\] are placed in the same plane with their centres coinciding. If \[{{R}_{1}}>>{{R}_{2}}\], the mutual inductance M between them will be directly proportional to [MP PMT 1994; MP PET 2001] |
| A. | \[{{R}_{1}}/{{R}_{2}}\] |
| B. | \[{{R}_{2}}/{{R}_{1}}\] |
| C. | \[R_{1}^{2}/{{R}_{2}}\] |
| D. | \[R_{2}^{2}/{{R}_{1}}\] |
| Answer» E. | |
| 8087. |
A short bar magnet with its north pole facing north forms a neutral point at P in the horizontal plane. If the magnet is rotated by 90o in the horizontal plane, the net magnetic induction at P is (Horizontal component of earth?s magnetic field = \[{{B}_{H}}\]) [EAMCET (Engg.) 2000] |
| A. | 0 |
| B. | 2 BH |
| C. | \[\frac{\sqrt{5}}{2}{{B}_{H}}\] |
| D. | \[\sqrt{5}\,{{B}_{H}}\] |
| Answer» E. | |
| 8088. |
A cell is connected between the points A and C of a circular conductor ABCD of centre O with angle A\[OC={{60}^{o}}\]. If \[{{B}_{1}}\] and \[{{B}_{2}}\] are the magnitudes of the magnetic fields at O due to the currents in ABC and ADC respectively, the ratio \[\frac{{{B}_{1}}}{{{B}_{2}}}\] is [KCET 1999; Pb PET 2000] |
| A. | 0.2 |
| B. | 6 |
| C. | 1 |
| D. | 5 |
| Answer» D. 5 | |
| 8089. |
Water boils in an electric kettle in 15 minutes after switching on. If the length of the heating wire is decreased to \[2/3\] of its initial value, then the same amount of water will boil with the same supply voltage in [MP PMT 1994] |
| A. | 15 minutes |
| B. | 12 minutes |
| C. | 10 minutes |
| D. | 8 minutes |
| Answer» D. 8 minutes | |
| 8090. |
Two identical flutes produce fundamental notes of frequency 300 Hz at \[{{27}^{o}}\]C. If the temperature of air in one flute is increased to \[{{31}^{o}}\]C, the number of the beats heard per second will be [UPSEAT 2002] |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 8091. |
Three rods made of the same material and having the same cross section have been joined as shown in the figure. Each rod is of the same length. The left and right ends are kept at \[{{0}^{o}}C\] and \[{{90}^{o}}C\] respectively. The temperature of the junction of the three rods will be [IIT-JEE (Screening) 2001] |
| A. | \[{{45}^{o}}C\] |
| B. | \[{{60}^{o}}C\] |
| C. | \[{{30}^{o}}C\] |
| D. | \[{{20}^{o}}C\] |
| Answer» C. \[{{30}^{o}}C\] | |
| 8092. |
A monoatomic ideal gas, initially at temperature \[{{T}_{1}},\] is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature. \[{{T}_{2}}\] by releasing the piston suddenly. If \[{{L}_{1}}\] and \[{{L}_{2}}\]are the lengths of the gas column before and after expansion respectively, then \[{{T}_{1}}/{{T}_{2}}\] is given by [IIT-JEE (Screening) 2000] |
| A. | \[{{\left( \frac{{{L}_{1}}}{{{L}_{2}}} \right)}^{2/3}}\] |
| B. | \[\frac{{{L}_{1}}}{{{L}_{2}}}\] |
| C. | \[\frac{{{L}_{2}}}{{{L}_{1}}}\] |
| D. | \[{{\left( \frac{{{L}_{2}}}{{{L}_{1}}} \right)}^{2/3}}\] |
| Answer» E. | |
| 8093. |
A glass flask of volume one litre at 0°C is filled, level full of mercury at this temperature. The flask and mercury are now heated to 100°C. How much mercury will spill out, if coefficient of volume expansion of mercury is \[1.82\times {{10}^{-4}}/{}^\circ C\] and linear expansion of glass is\[0.1\times {{10}^{-4}}/{}^\circ C\] respectively [MNR 1994] |
| A. | 21.2 cc |
| B. | 15.2 cc |
| C. | 1.52 cc |
| D. | 2.12 cc |
| Answer» C. 1.52 cc | |
| 8094. |
A body floats in a liquid contained in a beaker. The whole system as shown falls freely under gravity. The upthrust on the body due to the liquid is [IIT-JEE 1982] |
| A. | Zero |
| B. | Equal to the weight of the liquid displaced |
| C. | Equal to the weight of the body in air |
| D. | Equal to the weight of the immersed position of the body |
| Answer» B. Equal to the weight of the liquid displaced | |
| 8095. |
The resistance of a wire is \[{{10}^{-6}}\Omega \] per metre. It is bend in the form of a circle of diameter \[2\,m\]. A wire of the same material is connected across its diameter. The total resistance across its diameter AB will be |
| A. | \[\frac{4}{3}\pi \times {{10}^{-6}}\Omega \] |
| B. | \[\frac{2}{3}\pi \times {{10}^{-6}}\Omega \] |
| C. | \[0.88\times {{10}^{-6}}\Omega \] |
| D. | \[14\pi \times {{10}^{-6}}\Omega \] |
| Answer» D. \[14\pi \times {{10}^{-6}}\Omega \] | |
| 8096. |
A vector \[\overrightarrow{a}\] is turned without a change in its length through a small angle \[d\theta .\]The value of \[|\Delta \overrightarrow{a}|\] and \[\Delta a\] are respectively |
| A. | \[0,\,a\,d\theta \] |
| B. | \[a\,d\theta ,\,0\,\] |
| C. | 0, 0 |
| D. | None of these |
| Answer» C. 0, 0 | |
| 8097. |
If on the concentric hollow spheres of radii \[r\] and \[R(>r)\] the charge \[Q\] is distributed such that their surface densities are same then the potential at their common centre is [IIT 1981; MP PMT 2003] |
| A. | \[\frac{Q({{R}^{2}}+{{r}^{2}})}{4\pi {{\varepsilon }_{0}}(R+r)}\] |
| B. | \[\frac{QR}{R+r}\] |
| C. | Zero |
| D. | \[\frac{Q(R+r)}{4\pi {{\varepsilon }_{0}}({{R}^{2}}+{{r}^{2}})}\] |
| Answer» E. | |
| 8098. |
A room (cubical) is made of mirrors. An insect is moving along the diagonal on the floor such that the velocity of image of insect on two adjacent wall mirrors is 10 cms?1. The velocity of image of insect in ceiling mirror is |
| A. | 10 cms?1 |
| B. | 20 cms?1 |
| C. | \[\frac{10}{\sqrt{2}}\] cms?1 |
| D. | \[10\sqrt{2}\] cms?1 |
| Answer» E. | |
| 8099. |
The slopes of anode and mutual characteristics of a triode are 0.02 mA V?1 and 1 mA V?1 respectively. What is the amplification factor of the valve [MP PMT 1990] |
| A. | 5 |
| B. | 50 |
| C. | 500 |
| D. | 0.5 |
| Answer» C. 500 | |
| 8100. |
A and B are two radioactive substances whose half lives are 1 and 2 years respectively. Initially 10 gm of A and 1 gm of B is taken. The time (approximate) after which they will have same quantity remaining is [UPSEAT 2003] |
| A. | 6.62 years |
| B. | 5 years |
| C. | 3.2 years |
| D. | 7 years |
| Answer» B. 5 years | |