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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.
| 3901. |
Pressure inside two soap bubbles are 1.01 and 1.02 atmospheres. Ratio between their volumes is [MP PMT 1991] |
| A. | 102 : 101 |
| B. | \[{{\left( 102 \right)}^{3}}:{{\left( 101 \right)}^{3}}\] |
| C. | 8 : 1 |
| D. | 2 : 1 |
| Answer» D. 2 : 1 | |
| 3902. |
A soap bubble assumes a spherical surface. Which of the following statement is wrong [NCERT 1976] |
| A. | The soap film consists of two surface layers of molecules back to back |
| B. | The bubble encloses air inside it |
| C. | The pressure of air inside the bubble is less than the atmospheric pressure; that is why the atmospheric pressure has compressed it equally from all sides to give it a spherical shape |
| D. | Because of the elastic property of the film, it will tend to shrink to as small a surface area as possible for the volume it has enclosed |
| Answer» D. Because of the elastic property of the film, it will tend to shrink to as small a surface area as possible for the volume it has enclosed | |
| 3903. |
A body of density \[{{d}_{1}}\]is counterpoised by \[Mg\] of weights of density \[{{d}_{2}}\] in air of density d. Then the true mass of the body is |
| A. | M |
| B. | \[M\,\left( 1-\frac{d}{{{d}_{2}}} \right)\] |
| C. | \[M\left( 1-\frac{d}{{{d}_{1}}} \right)\] |
| D. | \[\frac{M(1-d/{{d}_{2}})}{(1-d/{{d}_{1}})}\] |
| Answer» E. | |
| 3904. |
Equal masses of water and a liquid of density 2 are mixed together, then the mixture has a density of |
| A. | 2/3 |
| B. | 4/3 |
| C. | 3/2 |
| D. | 3 |
| Answer» C. 3/2 | |
| 3905. |
Density of ice is \[\rho \] and that of water is \[\sigma \]. What will be the decrease in volume when a mass M of ice melts |
| A. | \[\frac{M}{\sigma -\rho }\] |
| B. | \[\frac{\sigma -\rho }{M}\] |
| C. | \[M\,\left[ \frac{1}{\rho }-\frac{1}{\sigma } \right]\] |
| D. | \[\frac{1}{M}\left[ \frac{1}{\rho }-\frac{1}{\sigma } \right]\] |
| Answer» D. \[\frac{1}{M}\left[ \frac{1}{\rho }-\frac{1}{\sigma } \right]\] | |
| 3906. |
The height of a mercury barometer is 75 cm at sea level and 50 cm at the top of a hill. Ratio of density of mercury to that of air is 104. The height of the hill is |
| A. | 250 m |
| B. | 2.5 km |
| C. | 1.25 km |
| D. | 750 m |
| Answer» C. 1.25 km | |
| 3907. |
A uniformly tapering vessel is filled with a liquid of density 900 kg/m3. The force that acts on the base of the vessel due to the liquid is \[(g=10\,m{{s}^{-2}})\] |
| A. | 3.6 N |
| B. | 7.2 N |
| C. | 9.0 N |
| D. | 14.4 N |
| Answer» C. 9.0 N | |
| 3908. |
Radius of an air bubble at the bottom of the lake is r and it becomes 2r when the air bubbles rises to the top surface of the lake. If P cm of water be the atmospheric pressure, then the depth of the lake is [Kerla PET 2005] |
| A. | 2p |
| B. | 8p |
| C. | 4p |
| D. | 7p |
| Answer» E. | |
| 3909. |
An inverted bell lying at the bottom of a lake 47.6 m deep has 50 cm3 of air trapped in it. The bell is brought to the surface of the lake. The volume of the trapped air will be (atmospheric pressure = 70 cm of Hg and density of Hg = 13.6 g/cm3) [CPMT 1989] |
| A. | 350 cm3 |
| B. | 300 cm3 |
| C. | 250 cm3 |
| D. | 22 cm3 |
| Answer» C. 250 cm3 | |
| 3910. |
Why the dam of water reservoir is thick at the bottom [AFMC 2005] |
| A. | Quantity of water increases with depth |
| B. | Density of water increases with depth |
| C. | Pressure of water increases with depth |
| D. | Temperature of water increases with depth |
| Answer» D. Temperature of water increases with depth | |
| 3911. |
A given shaped glass tube having uniform cross section is filled with water and is mounted on a rotatable shaft as shown in figure. If the tube is rotated with a constant angular velocity \[\omega \]then [AIIMS 2005] |
| A. | Water levels in both sections A and B go up |
| B. | Water level in Section A goes up and that in B comes down |
| C. | Water level in Section A comes down and that in B it goes up |
| D. | Water levels remains same in both sections |
| Answer» B. Water level in Section A goes up and that in B comes down | |
| 3912. |
Three liquids of densities \[d,\,2d\] and \[3d\] are mixed in equal proportions of weights. The relative density of the mixture is |
| A. | \[\frac{11d}{7}\] |
| B. | \[\frac{18d}{11}\] |
| C. | \[\frac{13d}{9}\] |
| D. | \[\frac{23d}{18}\] |
| Answer» C. \[\frac{13d}{9}\] | |
| 3913. |
Three liquids of densities \[d,\,2d\] and \[3d\] are mixed in equal volumes. Then the density of the mixture is |
| A. | d |
| B. | 2d |
| C. | 3d |
| D. | 5d |
| Answer» C. 3d | |
| 3914. |
With rise in temperature, density of a given body changes according to one of the following relations |
| A. | \[\rho ={{\rho }_{0}}[1+\gamma \,d\theta ]\] |
| B. | \[\rho ={{\rho }_{0}}[1-\gamma \,d\theta ]\] |
| C. | \[\rho ={{\rho }_{0}}\gamma d\theta \] |
| D. | \[\rho ={{\rho }_{0}}/\gamma d\theta \] |
| Answer» C. \[\rho ={{\rho }_{0}}\gamma d\theta \] | |
| 3915. |
The density \[\rho \] of water of bulk modulus B at a depth y in the ocean is related to the density at surface \[{{\rho }_{0}}\] by the relation |
| A. | \[\rho ={{\rho }_{0}}\left[ 1-\frac{{{\rho }_{0}}gy}{B} \right]\] |
| B. | \[\rho ={{\rho }_{0}}\left[ 1+\frac{{{\rho }_{0}}gy}{B} \right]\] |
| C. | \[\rho ={{\rho }_{0}}\left[ 1+\frac{Beta }{{{\rho }_{0}}hgy} \right]\] |
| D. | \[\rho ={{\rho }_{0}}\left[ 1-\frac{B}{{{\rho }_{0}}gy} \right]\] |
| Answer» C. \[\rho ={{\rho }_{0}}\left[ 1+\frac{Beta }{{{\rho }_{0}}hgy} \right]\] | |
| 3916. |
If two liquids of same volume but different densities \[{{\rho }_{1}}\] and \[{{\rho }_{2}}\] are mixed, then density of mixture is given by |
| A. | \[\rho =\frac{{{\rho }_{1}}+{{\rho }_{2}}}{2}\] |
| B. | \[\rho =\frac{{{\rho }_{1}}+{{\rho }_{2}}}{2{{\rho }_{1}}{{\rho }_{2}}}\] |
| C. | \[\rho =\frac{2{{\rho }_{1}}{{\rho }_{2}}}{{{\rho }_{1}}+{{\rho }_{2}}}\] |
| D. | \[\rho =\frac{{{\rho }_{1}}{{\rho }_{2}}}{{{\rho }_{1}}+{{\rho }_{2}}}\] |
| Answer» B. \[\rho =\frac{{{\rho }_{1}}+{{\rho }_{2}}}{2{{\rho }_{1}}{{\rho }_{2}}}\] | |
| 3917. |
If two liquids of same masses but densities \[{{\rho }_{1}}\] and \[{{\rho }_{2}}\] respectively are mixed, then density of mixture is given by |
| A. | \[\rho =\frac{{{\rho }_{1}}+{{\rho }_{2}}}{2}\] |
| B. | \[\rho =\frac{{{\rho }_{1}}+{{\rho }_{2}}}{2{{\rho }_{1}}{{\rho }_{2}}}\] |
| C. | \[\rho =\frac{2{{\rho }_{1}}{{\rho }_{2}}}{{{\rho }_{1}}+{{\rho }_{2}}}\] |
| D. | \[\rho =\frac{{{\rho }_{1}}{{\rho }_{2}}}{{{\rho }_{1}}+{{\rho }_{2}}}\] |
| Answer» D. \[\rho =\frac{{{\rho }_{1}}{{\rho }_{2}}}{{{\rho }_{1}}+{{\rho }_{2}}}\] | |
| 3918. |
A triangular lamina of area A and height h is immersed in a liquid of density \[\rho \] in a vertical plane with its base on the surface of the liquid. The thrust on the lamina is |
| A. | \[\frac{1}{2}A\rho gh\] |
| B. | \[\frac{1}{3}A\rho gh\] |
| C. | \[\frac{1}{6}A\rho gh\] |
| D. | \[\frac{2}{3}A\rho gh\] |
| Answer» C. \[\frac{1}{6}A\rho gh\] | |
| 3919. |
Two bodies are in equilibrium when suspended in water from the arms of a balance. The mass of one body is 36 g and its density is 9 g / cm3. If the mass of the other is 48 g, its density in g / cm3 is [CBSE PMT 1994] |
| A. | \[\frac{4}{3}\] |
| B. | \[\frac{3}{2}\] |
| C. | 3 |
| D. | 5 |
| Answer» D. 5 | |
| 3920. |
The height to which a cylindrical vessel be filled with a homogeneous liquid, to make the average force with which the liquid presses the side of the vessel equal to the force exerted by the liquid on the bottom of the vessel, is equal to |
| A. | Half of the radius of the vessel |
| B. | Radius of the vessel |
| C. | One-fourth of the radius of the vessel |
| D. | Three-fourth of the radius of the vessel |
| Answer» C. One-fourth of the radius of the vessel | |
| 3921. |
A barometer tube reads 76 cm of mercury. If the tube is gradually inclined at an angle of 60o with vertical, keeping the open end immersed in the mercury reservoir, the length of the mercury column will be |
| A. | 152 cm |
| B. | 76 cm |
| C. | 38 cm |
| D. | \[38\sqrt{3}cm\] |
| Answer» B. 76 cm | |
| 3922. |
A closed rectangular tank is completely filled with water and is accelerated horizontally with an acceleration a towards right. Pressure is (i) maximum at, and (ii) minimum at |
| A. | (i) B (ii) D |
| B. | (i) C (ii) D |
| C. | (i) B (ii) C |
| D. | (i) B (ii) A |
| Answer» B. (i) C (ii) D | |
| 3923. |
A beaker containing a liquid is kept inside a big closed jar. If the air inside the jar is continuously pumped out, the pressure in the liquid near the bottom of the liquid will |
| A. | Increases |
| B. | Decreases |
| C. | Remain constant |
| D. | First decrease and then increase |
| Answer» C. Remain constant | |
| 3924. |
The value of g at a place decreases by 2%. The barometric height of mercury |
| A. | Increases by 2% |
| B. | Decreases by 2% |
| C. | Remains unchanged |
| D. | Sometimes increases and sometimes decreases |
| Answer» B. Decreases by 2% | |
| 3925. |
The volume of an air bubble becomes three times as it rises from the bottom of a lake to its surface. Assuming atmospheric pressure to be 75 cm of Hg and the density of water to be 1/10 of the density of mercury, the depth of the lake is [AMU 1995] |
| A. | 5 m |
| B. | 10 m |
| C. | 15 m |
| D. | 20 m |
| Answer» D. 20 m | |
| 3926. |
The pressure at the bottom of a tank containing a liquid does not depend on [Kerala (Engg.) 2002] |
| A. | Acceleration due to gravity |
| B. | Height of the liquid column |
| C. | Area of the bottom surface |
| D. | Nature of the liquid |
| Answer» D. Nature of the liquid | |
| 3927. |
When a large bubble rises from the bottom of a lake to the surface. Its radius doubles. If atmospheric pressure is equal to that of column of water height H, then the depth of lake is [AIIMS 1995; AFMC 1997] |
| A. | H |
| B. | 2H |
| C. | 7H |
| D. | 8H |
| Answer» D. 8H | |
| 3928. |
If pressure at half the depth of a lake is equal to 2/3 pressure at the bottom of the lake then what is the depth of the lake [RPET 2000] |
| A. | 10 m |
| B. | 20 m |
| C. | 60 m |
| D. | 30 m |
| Answer» C. 60 m | |
| 3929. |
Power of a water pump is 2 kW. If \[g=10\,m/{{\sec }^{2}}\], the amount of water it can raise in one minute to a height of 10 m is [CBSE PMT 1990; Kerala PMT 2004] |
| A. | 2000 litre |
| B. | 1000 litre |
| C. | 100 litre |
| D. | 1200 litre |
| Answer» E. | |
| 3930. |
A weight lifter lifts 300 kg from the ground to a height of 2 meter in 3 second. The average power generated by him is [CPMT 1989; JIPMER 2001,02] |
| A. | 5880 watt |
| B. | 4410 watt |
| C. | 2205 watt |
| D. | 1960 watt |
| Answer» E. | |
| 3931. |
An electric motor creates a tension of 4500 newton in a hoisting cable and reels it in at the rate of 2 m/sec. What is the power of electric motor [MNR 1984] |
| A. | 15 kW |
| B. | 9 kW P = Fv \[=4500\times 2=9000\,W=9\,kW\] |
| C. | 225 W |
| D. | 9000 HP |
| Answer» E. | |
| 3932. |
An electric motor exerts a force of 40 N on a cable and pulls it by a distance of 30 m in one minute. The power supplied by the motor (in Watts) is [EAMCET 1984] |
| A. | 20 |
| B. | 200 |
| C. | 2 |
| D. | 10 |
| Answer» B. 200 | |
| 3933. |
A motor boat is travelling with a speed of 3.0 m/sec. If the force on it due to water flow is 500 N, the power of the boat is [EAMCET 1982] |
| A. | 150 kW |
| B. | 15 kW |
| C. | 1.5 kW |
| D. | 150 W |
| Answer» D. 150 W | |
| 3934. |
A 12 HP motor has to be operated 8 hours/day. How much will it cost at the rate of 50 paisa/kWh in 10 days |
| A. | Rs. 350/- |
| B. | Rs. 358/- |
| C. | Rs. 375/- |
| D. | Rs. 397/- |
| Answer» C. Rs. 375/- | |
| 3935. |
A man does a given amount of work in 10 sec. Another man does the same amount of work in 20 sec. The ratio of the output power of first man to the second man is [J&K CET 2005] |
| A. | 1 |
| B. | 1/2 |
| C. | 2/1 |
| D. | None of these |
| Answer» D. None of these | |
| 3936. |
If the heart pushes 1 cc of blood in one second under pressure 20000 N/m2 the power of heart is [J&K CET 2005] |
| A. | 0.02 W |
| B. | 400 W |
| C. | 5 × 10?10 W |
| D. | 0.2 W |
| Answer» B. 400 W | |
| 3937. |
From an automatic gun a man fires 360 bullet per minute with a speed of 360 km/hour. If each weighs 20 g, the power of the gun is [Pb. PET 2003] |
| A. | \[600W\] |
| B. | \[300W\] |
| C. | \[150W\] |
| D. | \[75W\] |
| Answer» B. \[300W\] | |
| 3938. |
The power of pump, which can pump 200 kg of water to a height of 50 m in 10 sec, will be [DPMT 2003] |
| A. | \[10\times {{10}^{3}}\,watt\] |
| B. | \[20\times {{10}^{3}}\,watt\] |
| C. | \[4\times {{10}^{3\,}}watt\] |
| D. | \[60\times {{10}^{3}}\,watt\] |
| Answer» B. \[20\times {{10}^{3}}\,watt\] | |
| 3939. |
A force of \[2\hat{i}+3\hat{j}+4\hat{k}\ N\]acts on a body for 4 second, produces a displacement of \[(3\hat{i}+4\hat{j}+5\hat{k})m.\]The power used is [Pb. PET 2001; CBSE PMT 2001] |
| A. | 9.5 W |
| B. | 7.5 W |
| C. | 6.5 W |
| D. | 4.5 W |
| Answer» B. 7.5 W | |
| 3940. |
An engine pumps up 100 kg of water through a height of 10 m in 5 s. Given that the efficiency of the engine is 60% . If \[g=10m{{s}^{-2}}\], the power of the engine is [DPMT 2004] |
| A. | \[3.3kW\] |
| B. | \[0.33kW\] |
| C. | \[0.033kW\] |
| D. | \[33kW\] |
| Answer» B. \[0.33kW\] | |
| 3941. |
A quarter horse power motor runs at a speed of 600 r.p.m. Assuming 40% efficiency the work done by the motor in one rotation will be [Kerala PET 2002] |
| A. | 7.46 J |
| B. | 7400 J |
| C. | 7.46 ergs |
| D. | 74.6 J |
| Answer» B. 7400 J | |
| 3942. |
A car of mass 1000 kg accelerates uniformly from rest to a velocity of 54 km/hour in 5s. The average power of the engine during this period in watts is (neglect friction) [Kerala PET 2002] |
| A. | 2000 W |
| B. | 22500 W |
| C. | 5000 W |
| D. | 2250 W |
| Answer» C. 5000 W | |
| 3943. |
A body of mass m accelerates uniformly from rest to \[{{v}_{1}}\] in time \[{{t}_{1}}\]. As a function of time t, the instantaneous power delivered to the body is [AIEEE 2004] |
| A. | \[\frac{m{{v}_{1}}t}{{{t}_{1}}}\] |
| B. | \[\frac{mv_{1}^{2}t}{{{t}_{1}}}\] |
| C. | \[\frac{m{{v}_{1}}{{t}^{2}}}{{{t}_{1}}}\] |
| D. | \[\frac{mv_{1}^{2}t}{t_{1}^{2}}\] |
| Answer» E. | |
| 3944. |
A 60 kg man runs up a staircase in 12 seconds while a 50 kg man runs up the same staircase in 11, seconds, the ratio of the rate of doing their work is [AMU (Engg.) 2001] |
| A. | 6 : 5 |
| B. | 12 : 11 |
| C. | 11 : 10 |
| D. | 10 : 11 |
| Answer» D. 10 : 11 | |
| 3945. |
A truck of mass 30,000kg moves up an inclined plane of slope 1 in 100 at a speed of 30 kmph. The power of the truck is (given \[g=10m{{s}^{-1}})\] [Kerala (Engg.) 2001] |
| A. | 25 kW |
| B. | 10 kW |
| C. | 5 kW |
| D. | 2.5 kW |
| Answer» B. 10 kW | |
| 3946. |
A car of mass 1250 kg is moving at 30m/s. Its engine delivers 30 kW while resistive force due to surface is 750N. What max acceleration can be given in the car [RPET 2000] |
| A. | \[\frac{1}{3}\,m/{{s}^{2}}\] |
| B. | \[\frac{1}{4}m/{{s}^{2}}\] |
| C. | \[\frac{1}{5}\,m/{{s}^{2}}\] |
| D. | \[\frac{1}{6}\,m/{{s}^{2}}\] |
| Answer» D. \[\frac{1}{6}\,m/{{s}^{2}}\] | |
| 3947. |
A force applied by an engine of a train of mass \[2.05\times {{10}^{6}}kg\] changes its velocity from \[5m/s\] to 25\[m/s\] in \[5\] minutes. The power of the engine is [EAMCET 2001] |
| A. | \[1.025MW\] |
| B. | \[2.05MW\] |
| C. | \[5MW\] |
| D. | \[6MW\] |
| Answer» C. \[5MW\] | |
| 3948. |
A 10 H.P. motor pumps out water from a well of depth 20m and fills a water tank of volume 22380 litres at a height of 10m from the ground. the running time of the motor to fill the empty water tank is \[(g=10m{{s}^{-2}}\]) [EAMCET (Engg.) 2000] |
| A. | 5 minutes |
| B. | 10 minutes |
| C. | 15 minutes |
| D. | 20 minutes |
| Answer» D. 20 minutes | |
| 3949. |
The power of a pump, which can pump 200kg of water to a height of 200m in 10sec is \[(g=10m/{{s}^{2}})\] [CBSE PMT 2000] |
| A. | 40 kW |
| B. | 80 kW |
| C. | 400 kW |
| D. | 960 kW |
| Answer» B. 80 kW | |
| 3950. |
From a waterfall, water is falling down at the rate of 100 kg/s on the blades of turbine. If the height of the fall is 100 m, then the power delivered to the turbine is approximately equal to [KCET 1994; BHU 1997; MP PET 2000] |
| A. | 100 kW |
| B. | 10 kW |
| C. | 1 kW |
| D. | 1000 kW |
| Answer» B. 10 kW | |