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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.
| 601. |
A source of sound of frequency 600 Hz is placed inside water. The speed of sound in water is 1500 m/s and in air is 300 m/s. The frequency of sound recorded by an observer who is standing in air is [IIT-JEE Screening 2004] |
| A. | 200 Hz |
| B. | 3000 Hz |
| C. | 120 Hz |
| D. | 600 Hz |
| Answer» E. | |
| 602. |
A man, standing between two cliffs, claps his hands and starts hearing a series of echoes at intervals of one second. If the speed of sound in air is 340 ms-1, the distance between the cliffs is [KCET 2004] |
| A. | 340 m |
| B. | 1620 m |
| C. | 680 m |
| D. | 1700 m |
| Answer» B. 1620 m | |
| 603. |
A person climbs up a stalled escalator in 60 sec. When he stands on it then he is carried in the moving escalator in 30 sec. How much time will he take in climbing up in a moving escalator? |
| A. | 10 sec |
| B. | 30 sec |
| C. | 20 sec |
| D. | 40 sec |
| Answer» D. 40 sec | |
| 604. |
Two balls of equal masses are thrown upwards, along the same vertical direction at an interval of 2 seconds, with the same initial velocity of 40 m/s. Then these collide at a height of (Take \[g=10\,m/{{s}^{2}}\]) |
| A. | 120 m |
| B. | 75 m |
| C. | 200 m |
| D. | 45 m |
| Answer» C. 200 m | |
| 605. |
The position of a particle vary \[x=4t-2{{t}^{2}}\]. The distance covered by particle in 4 s is |
| A. | 5 m |
| B. | 1 m |
| C. | 2 m |
| D. | 4 m |
| Answer» E. | |
| 606. |
Assertion : Heavy water is used as moderator in nuclear reactor. Reason : Water cool down the fast neutron. |
| 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. | |
| 607. |
A transistor is operated in common emitter configuration at \[{{V}_{C}}=2V\] such that a change in the base current from \[100\,\mu A\] to \[300\,\mu A\] produces a change in the collector current from \[10\,mA\] to\[20\,mA\]. The current gain is |
| A. | \[50\] |
| B. | \[75\] |
| C. | \[100\] |
| D. | \[25\] |
| Answer» B. \[75\] | |
| 608. |
Hydrogen atom emits blue light when it changes from n = 4 energy level to the n = 2 level. Which colour of light would the atom emit when it changes from the n = 5 level to the n = 2 level [KCET 1993] |
| A. | Red |
| B. | Yellow |
| C. | Green |
| D. | Violet |
| Answer» E. | |
| 609. |
A car of weight W is on an inclined road that rises by 100 m over a distance of 1 Km and applies a constant frictional force \[\frac{W}{20}\] on the car. While moving uphill on the road at a speed of\[10\text{ }m{{s}^{-1}}\], the car needs power P. If it needs power \[\frac{P}{2}\] while moving downhill at speed v then value of v is: |
| A. | \[20m{{s}^{-1}}\] |
| B. | \[5m{{s}^{-1}}\] |
| C. | \[15m{{s}^{-1}}\] |
| D. | \[10m{{s}^{-1}}\] |
| Answer» D. \[10m{{s}^{-1}}\] | |
| 610. |
On increasing the number of electrons striking the anode of an X-ray tube, which one of the following parameters of the resulting X-rays would increase [SCRA 1998; DPMT 2000] |
| A. | Penetration power |
| B. | Frequency |
| C. | Wavelength |
| D. | Intensity |
| Answer» E. | |
| 611. |
The displacement x (in metres) of a particle performing simple harmonic motion is related to time t (in seconds) as \[x=0.05\cos \left( 4\,\pi \,t+\frac{\pi }{4} \right)\]. The frequency of the motion will be [MP PMT/PET 1998] |
| A. | 0.5 Hz |
| B. | 1.0 Hz |
| C. | 1.5 Hz |
| D. | 2.0 Hz |
| Answer» E. | |
| 612. |
A particle executing simple harmonic motion of amplitude 5 cm has maximum speed of 31.4 cm/s. The frequency of its oscillation is [CBSE PMT 2005] |
| A. | 3 Hz |
| B. | 2 Hz |
| C. | 4 Hz |
| D. | 1 Hz |
| Answer» E. | |
| 613. |
The temperature of cold junction and neutral temperature of a thermocouple are \[{{15}^{o}}C\] and \[{{280}^{o}}C\] respectively. The temperature of inversion is [AMU (Engg.) 1999] |
| A. | \[{{295}^{o}}C\] |
| B. | \[{{265}^{o}}C\] |
| C. | \[{{545}^{o}}C\] |
| D. | \[{{575}^{o}}C\] |
| Answer» D. \[{{575}^{o}}C\] | |
| 614. |
A pendulum made of a uniform wire of cross sectional area A has time period T. When an additional mass M is added to its bob, the time period changes to\[{{T}_{M}}\]. If the Young's modulus of the material of the wire is Y then\[\frac{1}{Y}\] is equal to: (g = gravitational acceleration) |
| A. | \[\left[ 1-{{\left( \frac{{{T}_{M}}}{T} \right)}^{2}} \right]\frac{A}{Mg}\] |
| B. | \[\left[ 1-{{\left( \frac{T}{{{T}_{M}}} \right)}^{2}} \right]\frac{A}{Mg}\] |
| C. | \[\left[ {{\left( \frac{{{T}_{M}}}{T} \right)}^{2}}-1 \right]\frac{A}{Mg}\] |
| D. | \[\left[ {{\left( \frac{{{T}_{M}}}{T} \right)}^{2}}-1 \right]\frac{Mg}{A}\] |
| Answer» D. \[\left[ {{\left( \frac{{{T}_{M}}}{T} \right)}^{2}}-1 \right]\frac{Mg}{A}\] | |
| 615. |
The wavelength of yellow line of sodium is 5896 Å. Its wave number will be [MP PET 2001] |
| A. | 50883 × 1010 per second |
| B. | 16961 per cm |
| C. | 17581 per cm |
| D. | 50883 per cm |
| Answer» C. 17581 per cm | |
| 616. |
As per Bohr model, the minimum energy (in eV) required to remove an electron from the ground state of doubly ionized Li atom (Z = 3) is [IIT 1997 Re-Exam; MH CET 2000] |
| A. | 1.51 |
| B. | 13.6 |
| C. | 40.8 |
| D. | 122.4 |
| Answer» E. | |
| 617. |
A 100 kg piston encloses 32 g of oxygen gas at a temperature of \[{{27}^{o}}C\] in a vertical cylinder of base area of \[4\text{ }d{{m}^{2}}\]. The air pressure outside is \[1\times {{10}^{5}}Pa\]. The axis of the cylinder is vertical, and the piston can move in it without friction. How much heat is to be transferred to the gas to raise the piston by 20 cm. Use \[R=\frac{25}{3}J/mol/K\] |
| A. | 3500 J |
| B. | 350 J |
| C. | 7000 J |
| D. | 750 J |
| Answer» B. 350 J | |
| 618. |
Calculate the work done on the tool by \[\vec{F}\left( 11.25\hat{i}+11.25\hat{j} \right)N\] if the tool is first moved out along the x-axis to the point \[x=3.00m,\] \[y=0\] and then moved parallel to the y-axis to\[x=3.00m,\]\[y=3.00\text{ }m\]. |
| A. | 67.5 J |
| B. | 85 J |
| C. | 102 J |
| D. | 7.5 J |
| Answer» B. 85 J | |
| 619. |
Work done by a frictional force is |
| A. | Negative |
| B. | Positive |
| C. | Zero |
| D. | All of the above |
| Answer» E. | |
| 620. |
Which of the following is not a unit of energy [AIIMS 1985] |
| A. | \[W\text{-s}\]. |
| B. | \[kg\text{-}m/\sec \] |
| C. | \[N\text{-}m\] |
| D. | Joule |
| Answer» C. \[N\text{-}m\] | |
| 621. |
If the maximum velocity and acceleration of a particle executing SHM are equal in magnitude, the time period will be |
| A. | 1.57 sec |
| B. | 3.14 sec |
| C. | 6.28 sec |
| D. | 12.56 sec |
| Answer» D. 12.56 sec | |
| 622. |
Assertion : If three capacitors of capacitance \[{{C}_{\text{1}}} |
| 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. | |
| 623. |
The masses of the blocks A and B are 0.5 kg and 1 kg respectively. These are arranged as shown in the figure and are connected by a massless string. The coefficient of friction between all contact surfaces is 0.4. The force, necessary to move the block B with constant velocity, will be \[(g=10\,m/{{s}^{2}})\] |
| A. | 5 N |
| B. | 10 N |
| C. | 15 N |
| D. | 20 N |
| Answer» C. 15 N | |
| 624. |
The fringe width in Young?s double slit experiment increases when [MP PMT 2000] |
| A. | Wavelength increases |
| B. | Distance between the slits increases |
| C. | Distance between the source and screen decreases |
| D. | The width of the slits increases |
| Answer» B. Distance between the slits increases | |
| 625. |
In Young?s experiment, monochromatic light is used to illuminate the two slits A and B. Interference fringes are observed on a screen placed in front of the slits. Now if a thin glass plate is placed normally in the path of the beam coming from the slit [UPSEAT 1993, 2000; AIIMS 1999, 2004] |
| A. | The fringes will disappear |
| B. | The fringe width will increase |
| C. | The fringe width will increase |
| D. | There will be no change in the fringe width but the pattern shifts |
| Answer» E. | |
| 626. |
In a double slit experiment, instead of taking slits of equal widths, one slit is made twice as wide as the other. Then in the interference pattern [IIT-JEE (Screening) 2000] |
| A. | The intensities of both the maxima and the minima increase |
| B. | The intensity of maxima increases and the minima has zero intensity |
| C. | The intensity of maxima decreases and that of the minima increases |
| D. | The intensity of maxima decreases and the minima has zero intensity |
| Answer» B. The intensity of maxima increases and the minima has zero intensity | |
| 627. |
Two slits separated by a distance of 1 mm are illuminated with red light of wavelength\[6.5\times {{10}^{-7}}m\]. The interference fringes are observed on a screen placed 1 m from the silts. The distance of the third dark fringe from the central fringe will be equal to: |
| A. | 0.65 mm |
| B. | 1.30mm |
| C. | 1.62 mm |
| D. | 1.95mm |
| Answer» D. 1.95mm | |
| 628. |
Two masses of 1kg and 16kg are moving with equal K.E. The ratio of magnitude of the linear momentum is [AIEEE 2002] |
| A. | 1 : 2 |
| B. | 1 : 4 |
| C. | \[1\,:\,\sqrt{2}\] |
| D. | \[\sqrt{2}\,:\,1\] |
| Answer» C. \[1\,:\,\sqrt{2}\] | |
| 629. |
Assertion : The quantity L/R possesses dimensions of time. Reason : To reduce the rate of increases of current through a solenoid should increase the time constant (L/R). [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» C. If assertion is true but reason is false. | |
| 630. |
A liquid film is formed in a loop of area 0.05 m2. Increase in its potential energy will be (T = 0.2 N/m) [RPMT 2002] |
| A. | \[5\times {{10}^{-2}}J\] |
| B. | \[2\times {{10}^{-2}}J\] |
| C. | \[3\times {{10}^{-2}}J\] |
| D. | None of these |
| Answer» C. \[3\times {{10}^{-2}}J\] | |
| 631. |
GaAs is [RPMT 2000] |
| A. | Element semiconductor |
| B. | Alloy semiconductor |
| C. | Bad conductor |
| D. | Metallic semiconductor |
| Answer» C. Bad conductor | |
| 632. |
In case of a forced vibration, the resonance wave becomes very sharp when the [CBSE PMT 2003] |
| A. | Restoring force is small |
| B. | Applied periodic force is small |
| C. | Quality factor is small |
| D. | Damping force is small |
| Answer» E. | |
| 633. |
Resonance is an example of [CBSE PMT 1999; BHU 1999; 2005] |
| A. | Tuning fork |
| B. | Forced vibration |
| C. | Free vibration |
| D. | Damped vibration |
| Answer» C. Free vibration | |
| 634. |
A S.H.M. is represented by \[x=5\sqrt{2}(\sin 2\pi t+\cos 2\pi t).\]The amplitude of the S.H.M. is [MH CET 2004] |
| A. | 10 cm |
| B. | 20 cm |
| C. | \[5\sqrt{2}\]cm |
| D. | 50 cm |
| Answer» B. 20 cm | |
| 635. |
The equivalent inductance of two inductances is 2.4 henry when connected in parallel and 10 henry when connected in series. The difference between the two inductances is [MP PMT 2000] |
| A. | 2 henry |
| B. | 3 henry |
| C. | 4 henry |
| D. | 5 henry |
| Answer» B. 3 henry | |
| 636. |
Calculate the K.E and RE. of the ball half way up, when a ball of mass 0.1 kg is thrown vertically upwards with an initial speed of \[20\text{ }m{{s}^{-1}}\]. |
| A. | \[10\text{ }J,\text{ }20\text{ }J\] |
| B. | \[10\,J,\text{ }10\,J\] |
| C. | \[15\text{ }J,\text{ }8\text{ }J\] |
| D. | \[8\,J,16\,J\] |
| Answer» C. \[15\text{ }J,\text{ }8\text{ }J\] | |
| 637. |
Critical angle is that angle of incidence in the denser medium for which the angle of refraction in rarer medium is [MP PMT 1996] |
| A. | \[0{}^\circ \] |
| B. | \[57{}^\circ \] |
| C. | \[90{}^\circ \] |
| D. | \[180{}^\circ \] |
| Answer» D. \[180{}^\circ \] | |
| 638. |
A hospital uses an ultrasonic scanner to locate tumours in a tissue. The operating frequency of the scanner is 4.2 MHz. The speed of sound in a tissue is 1.7 km/s. The wavelength of sound in tissue is close to |
| A. | \[4\times {{10}^{-4}}m\] |
| B. | \[8\times {{10}^{-4}}m\] |
| C. | \[4\times {{10}^{-3}}m\] |
| D. | \[8\times {{10}^{-3}}m\] |
| Answer» B. \[8\times {{10}^{-4}}m\] | |
| 639. |
The distance between the body centred atom and a corner atom in sodium \[(a=4.225{AA})\] is [CBSE PMT 1995] |
| A. | \[3.66\,{AA}\] |
| B. | \[3.17\,{AA}\] |
| C. | \[2.99\,{AA}\] |
| D. | \[2.54\,{AA}\] |
| Answer» B. \[3.17\,{AA}\] | |
| 640. |
A simple pendulum is vibrating in an evacuated chamber, it will oscillate with [Pb. PMT 2004] |
| A. | Increasing amplitude |
| B. | Constant amplitude |
| C. | Decreasing amplitude |
| D. | First (c) then (a) |
| Answer» C. Decreasing amplitude | |
| 641. |
Beats are the result of [CPMT 1971; J & K CET 2002] |
| A. | Diffraction |
| B. | Destructive interference |
| C. | Constructive and destructive interference |
| D. | Superposition of two waves of nearly equal frequency |
| Answer» E. | |
| 642. |
The frequency of light ray having the wavelength 3000 Å is [DPMT 2002] |
| A. | 9 ´ 1013 cycles/sec |
| B. | 1015 cycles/sec |
| C. | 90 cycles/sec |
| D. | 3000 cycles/sec |
| Answer» C. 90 cycles/sec | |
| 643. |
Two coherent sources of different intensities send waves which interfere. The ratio of maximum intensity to the minimum intensity is 25. The intensities of the sources are in the ratio [UPSEAT 2002] |
| A. | 25 : 1 |
| B. | 5 : 1 |
| C. | 9 : 4 |
| D. | 25 : 16 |
| Answer» D. 25 : 16 | |
| 644. |
Two waves have their amplitudes in the ratio 1 : 9. The maximum and minimum intensities when they interfere are in the ratio [KCET 2002] |
| A. | \[\frac{25}{16}\] |
| B. | \[\frac{16}{26}\] |
| C. | \[\frac{1}{9}\] |
| D. | \[\frac{9}{1}\] |
| Answer» B. \[\frac{16}{26}\] | |
| 645. |
Penetrating power of X-rays does not depend on [MP PET 2001] |
| A. | Wavelength |
| B. | Energy |
| C. | Potential difference |
| D. | Current in the filament |
| Answer» E. | |
| 646. |
When \[{{10}^{14}}\] electrons are removed from a neutral metal sphere, the charge on the sphere becomes [Manipal JEE 1995] |
| A. | \[16\,\mu \,C\] |
| B. | \[-16\,\mu \,C\] |
| C. | \[32\,\mu \,C\] |
| D. | \[-32\,\mu \,C\] |
| Answer» B. \[-16\,\mu \,C\] | |
| 647. |
Assertion : The surface wave propagation is used for medium wave band and for television broadcasting. Reason : The surface waves travel directly from transmitting antenna to receiver antenna through atmosphere. |
| 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. | |
| 648. |
Every series of hydrogen spectrum has an upper and lower limit in wavelength. The spectral series which has an upper limit of wavelength equal to 18752 Å is [MP PMT 1993] |
| A. | Balmer series |
| B. | Lyman series |
| C. | Paschen series |
| D. | Pfund series (Rydberg constant \[R=1.097\times {{10}^{7}}\]per metre) |
| Answer» D. Pfund series (Rydberg constant \[R=1.097\times {{10}^{7}}\]per metre) | |
| 649. |
The phase difference between incident wave and reflected wave is \[180{}^\circ \] when light ray |
| A. | enters into glass from air |
| B. | enters into air from glass |
| C. | enters into glass from diamond |
| D. | enters into water from glass |
| Answer» B. enters into air from glass | |
| 650. |
One centimeter on the main scale of a vernier calipers is divided into 10 equal parts. If 10 divisions of vernier coincide with 8 small divisions of the main scale, the least count of vernier calipers is |
| A. | 0.01 cm |
| B. | 0.02 cm |
| C. | 0.05 cm |
| D. | 0.005 cm |
| Answer» C. 0.05 cm | |