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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.
| 8951. |
A part of a long wire carrying a current i is bent into a circle of radius r as shown in figure. The net magnetic field at the centre O of the circular loop is [UPSEAT 2002] |
| A. | \[\frac{{{\mu }_{o}}i}{4r}\] |
| B. | \[\frac{{{\mu }_{o}}i}{2r}\] |
| C. | \[\frac{{{\mu }_{o}}i}{2\pi r}(\pi +1)\] |
| D. | \[\frac{{{\mu }_{o}}i}{2\pi r}(\pi -1)\] |
| Answer» D. \[\frac{{{\mu }_{o}}i}{2\pi r}(\pi -1)\] | |
| 8952. |
If R is the radius of the earth and g the acceleration due to gravity on the earth's surface, the mean density of the earth is [CPMT 1990; BHU 1998; Kerala PMT 2002; MH CET (Med.) 1999; CBSE PMT 1995] |
| A. | \[4\pi G/3gR\] |
| B. | \[3\pi R/4gG\] |
| C. | \[3g/4\pi RG\] |
| D. | \[\pi RG/12G\] |
| Answer» D. \[\pi RG/12G\] | |
| 8953. |
Due to 10 ampere of current flowing in a circular coil of 10 cm radius, the magnetic field produced at its centre is \[3.14\times {{10}^{-3}}\,Weber/{{m}^{2}}\]. The number of turns in the coil will be [MP PET 1996] |
| A. | 5000 |
| B. | 100 |
| C. | 50 |
| D. | 25 |
| Answer» D. 25 | |
| 8954. |
A closed bottle containing water at 30°C is carried to the moon in a space-ship. If it is placed on the surface of the moon, what will happen to the water as soon as the lid is opened [RPMT 2002] |
| A. | Water will boil |
| B. | Water will freeze |
| C. | Nothing will happen on it |
| D. | It will decompose into \[{{H}_{2}}\] and \[{{O}_{2}}\] |
| Answer» B. Water will freeze | |
| 8955. |
At the surface of a certain planet, acceleration due to gravity is one-quarter of that on earth. If a brass ball is transported to this planet, then which one of the following statements is not correct [SCRA 1994] |
| A. | The mass of the brass ball on this planet is a quarter of its mass as measured on earth |
| B. | The weight of the brass ball on this planet is a quarter of the weight as measured on earth |
| C. | The brass ball has the same mass on the other planet as on earth |
| D. | The brass ball has the same volume on the other planet as on earth |
| Answer» B. The weight of the brass ball on this planet is a quarter of the weight as measured on earth | |
| 8956. |
Assertion : The colour of the green flower seen through red glass appears to be dark. Reason : Red glass transmits only red light. [AIIMS 1997] |
| 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. | |
| 8957. |
Assertion : The focal length of the mirror is f and distance of the object from the focus is u, the magnification of the mirror is f / u. Reason : Magnification \[=\frac{\text{Size of image}}{\text{Size of object}}\] [AIIMS 1994] |
| 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. | |
| 8958. |
Assertion : Different colours travel with different speed in vacuum. Reason : Wavelength of light depends on refractive index of medium. [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» F. | |
| 8959. |
The SI unit of mechanical equivalent of heat is [MP PMT/PET 1998] |
| A. | Joule ´ Calorie |
| B. | Joule/Calorie |
| C. | Calorie ´ Erg |
| D. | Erg/Calorie |
| Answer» C. Calorie ´ Erg | |
| 8960. |
If water rises in a capillary tube upto 3 cm. What is the diameter of capillary tube (Surface tension of water\[=\text{ }7.2\text{ }\times {{10}^{2}}N/m\]) [RPMT 2002] |
| A. | \[9.6\times {{10}^{4}}m\] |
| B. | \[9.6\times {{10}^{3}}m\] |
| C. | \[9.6\times {{10}^{2}}m\] |
| D. | \[9.6\times {{10}^{1}}m\] |
| Answer» B. \[9.6\times {{10}^{3}}m\] | |
| 8961. |
Taking Rydberg?s constant \[{{R}_{H}}=1.097\times {{10}^{7}}m\] first and second wavelength of Balmer series in hydrogen spectrum is [Pb. PMT 2004] |
| A. | 2000 Å, 3000 Å |
| B. | 1575 Å, 2960 Å |
| C. | 6529 Å, 4280 Å |
| D. | 6552 Å, 4863 Å |
| Answer» E. | |
| 8962. |
Assertion : Earth has an atmosphere but the moon does not. Reason : Moon is very small in comparison to earth. |
| 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. | |
| 8963. |
The energy of hydrogen atom in its ground state is ? 13.6 eV. The energy of the level corresponding to the quantum number n is equal 5 is [KCET (Engg./Med.) 2001] |
| A. | ? 5.40 eV |
| B. | ? 2.72 eV |
| C. | ? 0.85 eV |
| D. | ? 0.54 eV |
| Answer» E. | |
| 8964. |
A 0.7 henry inductor is connected across a 120V ? 60 Hz ac source. The current in the inductor will be very nearly [MP PMT 2002] |
| A. | 4.55 amp |
| B. | 0.355 amp |
| C. | 0.455 amp |
| D. | 3.55 amp |
| Answer» D. 3.55 amp | |
| 8965. |
Assertion : The velocity increases, when water flowing in broader pipe enter a narrow pipe. Reason : According to equation of continuity, product of area and velocity is constant. |
| 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. | |
| 8966. |
Work done by an external agent in separating the parallel plate capacitor is [AIEEE 2002] |
| A. | \[CV\] |
| B. | \[\frac{1}{2}{{C}^{2}}V\] |
| C. | \[\frac{1}{2}C{{V}^{2}}\] |
| D. | None of these |
| Answer» D. None of these | |
| 8967. |
A particle executes harmonic motion with an angular velocity and maximum acceleration of 3.5 rad/sec and 7.5 m/s2 respectively. The amplitude of oscillation is [AIIMS 1999; Pb. PET 1999] |
| A. | 0.28 m |
| B. | 0.36 m |
| C. | 0.53 m |
| D. | 0.61 m |
| Answer» E. | |
| 8968. |
A circular coil of radius R carries an electric current. The magnetic field due to the coil at a point on the axis of the coil located at a distance r from the centre of the coil, such that r >> R, varies as [EAMCET 1987; AIIMS 2004] |
| A. | \[\frac{1}{r}\] |
| B. | \[\frac{1}{{{r}^{3/2}}}\] |
| C. | \[\frac{1}{{{r}^{2}}}\] |
| D. | \[\frac{1}{{{r}^{3}}}\] |
| Answer» C. \[\frac{1}{{{r}^{2}}}\] | |
| 8969. |
For an ac circuit \[V=15\sin \omega t\] and \[I=20\cos \omega t\] the average power consumed in this circuit is [RPET 1999] |
| A. | 300 Watt |
| B. | 150 Watt |
| C. | 75 Watt |
| D. | zero |
| Answer» E. | |
| 8970. |
There is an air filled \[1pF\] parallel plate capacitor. When the plate separation is doubled and the space is filled with wax, the capacitance increases to\[2pF\]. The dielectric constant of wax is [MNR 1998; KCET 2005] |
| A. | 2 |
| B. | 4 |
| C. | 6 |
| D. | 8 |
| Answer» C. 6 | |
| 8971. |
Assertion : A piece of ice floats in water, the level of water remains unchanged when the ice melts completely. Reason : According to Archimede's principle, the loss in weight of the body in the liquid is equal to the weight of the liquid displaced by the immersed part 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. | |
| 8972. |
A wavelength 0.60 cm is produced in air and it travels at a speed of 300 ms?1. It will be an [UPSEAT 2000] |
| A. | Audible wave |
| B. | Infrasonic wave |
| C. | Ultrasonic wave |
| D. | None of the above |
| Answer» D. None of the above | |
| 8973. |
Speed of sound in mercury at a certain temperature is 1450 m/s. Given the density of mercury as 13.6 ´ 103 kg / m3, the bulk modulus for mercury is [JIPMER 2000] |
| A. | 2.86 ´1010 N/m3 |
| B. | 3.86 ´1010 N/m3 |
| C. | 4.86 ´1010 N/m3 |
| D. | 5.86 ´1010 N/m3 |
| Answer» B. 3.86 ´1010 N/m3 | |
| 8974. |
Assertion : Radio waves can be polarised. Reason : Sound waves in air are longitudinal in nature. [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» C. If assertion is true but reason is false. | |
| 8975. |
Assertion : The earth without atmosphere would be inhospitably cold. Reason : All heat would escape in the absence of atmosphere. [AIIMS 2002] |
| 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. | |
| 8976. |
Assertion : Environmental damage has increased the amount of ozone in the atmosphere. Reason : Increase of ozone increases the amount of ultraviolet radiation on earth. [AIIMS 1996] |
| 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. | |
| 8977. |
The pointer of a dead-beat galvanometer gives a steady deflection because [MP PMT 1994] |
| A. | Eddy currents are produced in the conducting frame over which the coil is wound |
| B. | Its magnet is very strong |
| C. | Its pointer is very light |
| D. | Its frame is made of abonite |
| Answer» B. Its magnet is very strong | |
| 8978. |
If the resultant of the two forces has a magnitude smaller than the magnitude of larger force, the two forces must be |
| A. | Different both in magnitude and direction |
| B. | Mutually perpendicular to one another |
| C. | Possess extremely small magnitude |
| D. | Point in opposite directions |
| Answer» E. | |
| 8979. |
Assertion : Work done by friction on a body sliding down an inclined plane is positive. Reason : Work done is greater than zero, if angle between force and displacement is acute or both are in same direction. |
| 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. | |
| 8980. |
The working of dynamo is based on principle of [CPMT 1984] |
| A. | Electromagnetic induction |
| B. | Conversion of energy into electricity |
| C. | Magnetic effects of current |
| D. | Heating effects of current |
| Answer» B. Conversion of energy into electricity | |
| 8981. |
Assertion : A large soap bubble expands while a small bubble shrinks, when they are connected to each other by a capillary tube. Reason : The excess pressure inside bubble (or drop) is inversely proportional to the radius. |
| 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. | |
| 8982. |
The mass of a particle is 400 times than that of an electron and the charge is double. The particle is accelerated by 5 V. Initially the particle remained in rest, then its final kinetic energy will be [MP PMT 1990] |
| A. | 5 eV |
| B. | 10 eV |
| C. | 100 eV |
| D. | 2000 eV |
| Answer» C. 100 eV | |
| 8983. |
A transformer with efficiency 80% works at 4 kW and 100 V. If the secondary voltage is 200 V, then the primary and secondary currents are respectively [Kerala PMT 2005] |
| A. | 40 A, 16 A |
| B. | 16 A, 40 A |
| C. | 20 A, 40 A |
| D. | 40 A, 20 A |
| Answer» B. 16 A, 40 A | |
| 8984. |
The magnetic field at the centre of current carrying coil is [CPMT 1996; RPET 2002, 03] |
| A. | \[\frac{{{\mu }_{0}}ni}{2r}\] |
| B. | \[\frac{{{\mu }_{0}}}{2\pi }\frac{ni}{r}\] |
| C. | \[\frac{{{\mu }_{0}}ni}{4r}\] |
| D. | \[{{\mu }_{0}}ni\] |
| Answer» B. \[\frac{{{\mu }_{0}}}{2\pi }\frac{ni}{r}\] | |
| 8985. |
What is the phase difference between two successive crests in the wave [RPMT 2001, 02; MH CET 2004] |
| A. | p |
| B. | p/2 |
| C. | 2p |
| D. | 4p |
| Answer» D. 4p | |
| 8986. |
A wave of frequency 500 Hz has velocity 360 m/sec. The distance between two nearest points 60° out of phase, is [NCERT 1979; MP PET 1989; JIPMER 1997; RPMT 2002, 03; CPMT 1979, 90, 2003; BCECE 2005] |
| A. | 0.6 cm |
| B. | 12 cm |
| C. | 60 cm |
| D. | 120 cm |
| Answer» C. 60 cm | |
| 8987. |
The vectors \[5i+8j\]and\[2i+7j\]are added. The magnitude of the sum of these vector is [BHU 2000] |
| A. | \[\sqrt{274}\] |
| B. | 38 |
| C. | 238 |
| D. | 560 |
| Answer» B. 38 | |
| 8988. |
The field due to a long straight wire carrying a current I is proportional to [MP PMT 1993] |
| A. | I |
| B. | \[{{I}^{3}}\] |
| C. | \[\sqrt{I}\] |
| D. | \[1/I\] |
| Answer» B. \[{{I}^{3}}\] | |
| 8989. |
The radio waves of frequency 300 MHz to 3000 MHz belong to [AMU 2002] |
| A. | High frequency band |
| B. | Very high frequency band |
| C. | Ultra high frequency band |
| D. | Super high frequency band |
| Answer» D. Super high frequency band | |
| 8990. |
Assertion : Corpuscular theory fails in explaining the velocities of light in air and water. Reason : According to corpuscular theory, light should travel faster in denser medium than, in rarer medium. [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. | |
| 8991. |
Assertion : Microwave communication is preferred over optical communication. Reason : Microwaves provide large number of channels and band width compared to optical signals. [AIIMS 2003] |
| 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. | |
| 8992. |
A lamp consumes only 50% of peak power in an a.c. circuit. What is the phase difference between the applied voltage and the circuit current [MP PMT 2004] |
| A. | \[\frac{\pi }{6}\] |
| B. | \[\frac{\pi }{3}\] |
| C. | \[\frac{\pi }{4}\] |
| D. | \[\frac{\pi }{2}\] |
| Answer» C. \[\frac{\pi }{4}\] | |
| 8993. |
When a body is taken from the equator to the poles, its weight [EAMCET 1978] |
| A. | Remains constant |
| B. | Increases |
| C. | Decreases |
| D. | Increases at N-pole and decreases at S-pole |
| Answer» C. Decreases | |
| 8994. |
The dielectric constant \[k\] of an insulator cannot be [CPMT 1974] |
| A. | 3 |
| B. | 6 |
| C. | 8 |
| D. | \[\infty \] |
| Answer» E. | |
| 8995. |
A transformer is used to [MP PET 1999] |
| A. | Change the alternating potential |
| B. | Change the alternating current |
| C. | To prevent the power loss in alternating current flow |
| D. | To increase the power of current source |
| Answer» B. Change the alternating current | |
| 8996. |
Assertion : The frequency of a second pendulum in an elevator moving up with an acceleration half the acceleration due to gravity is 0.612 s?1. Reason : The frequency of a second pendulum does not depend upon acceleration due to gravity. |
| 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. | |
| 8997. |
Assertion : Damped oscillation indicates loss of energy. Reason : The energy loss in damped oscillation may be due to friction, air resistance etc. |
| 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. | |
| 8998. |
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 | |
| 8999. |
An ideal transformer has 100 turns in the primary and 250 turns in the secondary. The peak value of the ac is 28 V. The r.m.s. secondary voltage is nearest to [MP PMT 1992] |
| A. | 50 V |
| B. | 70 V |
| C. | 100 V |
| D. | 40 V |
| Answer» B. 70 V | |
| 9000. |
Water rises upto a height h in a capillary on the surface of earth in stationary condition. Value of h increases if this tube is taken [RPET 2000] |
| A. | On sun |
| B. | On poles |
| C. | In a lift going upward with acceleration |
| D. | In a lift going downward with acceleration |
| Answer» E. | |