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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.
| 3751. |
According to Newton?s law of cooling, the rate of cooling of a body is proportional to \[{{(\Delta \theta )}^{n}}\], where \[\Delta \theta \] is the difference of the temperature of the body and the surroundings, and n is equal to [AIEEE 2003] |
| A. | One |
| B. | Two |
| C. | Three |
| D. | Four |
| Answer» B. Two | |
| 3752. |
A calorimeter of mass 0.2 kg and specific heat 900 J/kg-K. Containing 0.5 kg of a liquid of specific heat 2400J /kg-K. Its temperature falls from \[{{60}^{o}}C\,\text{to}\,\,\text{5}{{\text{5}}^{\text{o}}}C\] in one minute. The rate of cooling is [MP PET 2003] |
| A. | 5 J/s |
| B. | 15 J/s |
| C. | 100 J/s |
| D. | 115 J/s |
| Answer» E. | |
| 3753. |
It takes 10 minutes to cool a liquid from 61oC to 59oC. If room temperature is 30oC then time taken in cooling from 51oC to 49oC is [RPET 2003] |
| A. | 10 min |
| B. | 11 min |
| C. | 13 min |
| D. | 15 min |
| Answer» E. | |
| 3754. |
The temperature of a body falls from \[{{50}^{o}}C\]to \[{{40}^{o}}C\] in 10 minutes. If the temperature of the surroundings is \[{{20}^{o}}C\]Then temperature of the body after another 10 minutes will be [Pb. PMT 2002] |
| A. | \[{{36.6}^{o}}C\] |
| B. | \[{{33.3}^{o}}C\] |
| C. | \[{{35}^{o}}C\] |
| D. | \[{{30}^{o}}C\] |
| Answer» E. | |
| 3755. |
A body takes 5 minutes for cooling from \[{{50}^{o}}C\] to \[{{40}^{o}}C.\] Its temperature comes down to \[{{33.33}^{o}}C\] in next 5 minutes. Temperature of surroundings is [MP PMT 2002] |
| A. | \[{{15}^{o}}C\] |
| B. | \[{{20}^{o}}C\][L1] |
| C. | \[{{25}^{o}}C\] |
| D. | \[{{10}^{o}}C\] |
| Answer» C. \[{{25}^{o}}C\] | |
| 3756. |
A body cools in 7 minutes from \[{{60}^{o}}C\] to \[{{40}^{o}}C\] What time (in minutes) does it take to cool from \[{{40}^{o}}C\] to \[{{28}^{o}}C\] if the surrounding temperature is \[{{10}^{o}}C\]? Assume Newton?s Law of cooling holds [Kerala (Engg.) 2001] |
| A. | 3.5 |
| B. | 11 |
| C. | 7 |
| D. | 10 |
| Answer» D. 10 | |
| 3757. |
According to ?Newton?s Law of cooling?, the rate of cooling of a body is proportional to the [MP PET 2001] |
| A. | Temperature of the body |
| B. | Temperature of the surrounding |
| C. | Fourth power of the temperature of the body |
| D. | Difference of the temperature of the body and the surroundings |
| Answer» E. | |
| 3758. |
In a room where the temperature is \[{{30}^{o}}C\], a body cools from \[{{61}^{o}}C\] to \[{{59}^{o}}C\] in 4 minutes. The time (in min.) taken by the body to cool from \[{{51}^{0}}C\]to \[{{49}^{0}}C\] will be [UPSEAT 2000] |
| A. | 4 min |
| B. | 6 min |
| C. | 5 min |
| D. | 8 min |
| Answer» C. 5 min | |
| 3759. |
Newton?s law of cooling, holds good only if the temperature difference between the body and the surroundings is [BHU 2000] |
| A. | Less than \[{{10}^{o}}C\] |
| B. | More than \[{{10}^{o}}C\] |
| C. | Less than \[{{100}^{o}}C\] |
| D. | More than \[{{100}^{o}}C\] |
| Answer» B. More than \[{{10}^{o}}C\] | |
| 3760. |
Hot water kept in a beaker placed in a room cools from \[{{70}^{o}}C\] to 60°C in 4 minutes. The time taken by it to cool from \[{{69}^{o}}C\] to \[{{59}^{o}}c\] will be [JIPMER 1999] |
| A. | The same 4 minutes |
| B. | More than 4 minutes |
| C. | Less than 4 minutes |
| D. | We cannot say definitely |
| Answer» C. Less than 4 minutes | |
| 3761. |
A bucket full of hot water cools from \[{{75}^{o}}C\] to \[{{70}^{0}}C\] in time \[{{T}_{1}}\], from \[{{70}^{o}}C\] to \[{{65}^{o}}C\] in time \[{{T}_{2}}\] and from \[{{65}^{o}}C\] to \[{{60}^{o}}C\] in time \[{{T}_{3}}\], then [NCERT 1980; MP PET 1989; CBSE PMT 1995; KCET 2003; MH CET 1999] |
| A. | \[{{T}_{1}}={{T}_{2}}={{T}_{3}}\] |
| B. | \[{{T}_{1}}>{{T}_{2}}>{{T}_{3}}\] |
| C. | \[{{T}_{1}}<{{T}_{2}}<{{T}_{3}}\] |
| D. | \[{{T}_{1}}>{{T}_{2}}<{{T}_{3}}\] |
| Answer» D. \[{{T}_{1}}>{{T}_{2}}<{{T}_{3}}\] | |
| 3762. |
A body cools from \[{{50.0}^{o}}C\] to \[{{49.9}^{o}}C\] in \[5\ s\]. How long will it take to cool from \[{{40.0}^{o}}C\] to \[{{39.9}^{o}}C\]? Assume the temperature of surroundings to be \[{{30.0}^{o}}C\] and Newton's law of cooling to be valid [CBSE PMT 1994] |
| A. | 2.5 s |
| B. | 10 s |
| C. | 20 s |
| D. | 5 s |
| Answer» C. 20 s | |
| 3763. |
A container contains hot water at \[{{100}^{o}}C\]. If in time \[{{T}_{1}}\] temperature falls to \[{{80}^{o}}C\] and in time \[{{T}_{2}}\] temperature falls to \[{{60}^{o}}C\] from \[{{80}^{o}}C\], then [CPMT 1997] |
| A. | \[{{T}_{1}}={{T}_{2}}\] |
| B. | \[{{T}_{1}}>{{T}_{2}}\] |
| C. | \[{{T}_{1}}<{{T}_{2}}\] |
| D. | None |
| Answer» D. None | |
| 3764. |
A body cools from \[{{60}^{o}}C\] to \[{{50}^{o}}C\] in 10 minutes. If the room temperature is \[{{25}^{o}}C\] and assuming Newton's law of cooling to hold good, the temperature of the body at the end of the next 10 minutes will be [MP PMT/PET 1998; BHU 2000; Pb. PMT 2001] |
| A. | \[{{38.5}^{o}}C\] |
| B. | \[{{40}^{o}}C\] |
| C. | \[{{42.85}^{o}}C\] |
| D. | \[{{45}^{o}}C\] |
| Answer» D. \[{{45}^{o}}C\] | |
| 3765. |
The temperature of a liquid drops from \[365K\] to 361 K in 2 minutes. Find the time during which temperature of the liquid drops from \[344\ K\] to \[342K\]. Temperature of room is \[293\ K\] [RPET 1997] |
| A. | 84 sec |
| B. | 72 sec |
| C. | 66 sec |
| D. | 60 sec |
| Answer» B. 72 sec | |
| 3766. |
The rates of cooling of two different liquids put in exactly similar calorimeters and kept in identical surroundings are the same if [MP PMT/PET 1998] |
| A. | The masses of the liquids are equal |
| B. | Equal masses of the liquids at the same temperature are taken |
| C. | Different volumes of the liquids at the same temperature are taken |
| D. | Equal volumes of the liquids at the same temperature are taken |
| Answer» E. | |
| 3767. |
A liquid cools down from \[{{70}^{o}}C\] to \[{{60}^{o}}C\] in 5 minutes. The time taken to cool it from \[{{60}^{o}}C\] to \[{{50}^{o}}C\] will be [MP PET 1992, 2000; MP PMT 1996] |
| A. | 5 minutes |
| B. | Lesser than 5 minutes |
| C. | Greater than 5 minutes |
| D. | Lesser or greater than 5 minutes depending upon the density of the liquid |
| Answer» D. Lesser or greater than 5 minutes depending upon the density of the liquid | |
| 3768. |
If a metallic sphere gets cooled from \[{{62}^{o}}C\] to \[{{50}^{o}}C\] in \[{{40}^{o}}C\]and in the next \[10\ \min utes\]gets cooled to \[{{42}^{o}}C\], then the temperature of the surroundings is [MP PET 1997] |
| A. | \[{{30}^{o}}C\] |
| B. | \[{{36}^{o}}C\] |
| C. | \[{{26}^{o}}C\] |
| D. | \[{{20}^{o}}C\] |
| Answer» D. \[{{20}^{o}}C\] | |
| 3769. |
A cup of tea cools from \[{{80}^{0}}C\] to \[{{60}^{o}}C\] in one minute. The ambient temperature is \[{{30}^{o}}C\]. In cooling from \[{{60}^{o}}C\] to \[{{50}^{o}}C\] it will take [MP PMT 1995; UPSEAT 2000; MH CET 2002] |
| A. | \[30\ \sec onds\] |
| B. | \[60\ \sec onds\] |
| C. | \[90\ \sec onds\] |
| D. | \[50\ \sec onds\] |
| Answer» E. | |
| 3770. |
A body takes 4 minutes to cool from \[{{100}^{o}}C\] to \[{{70}^{o}}C\]. To cool from \[{{70}^{o}}C\] to \[{{40}^{o}}C\] it will take (room temperature is \[{{15}^{o}}C\]) [MP PET 1995] |
| A. | 7 minutes |
| B. | 6 minutes |
| C. | 5 minutes |
| D. | 4 minutes |
| Answer» C. 5 minutes | |
| 3771. |
We consider the radiation emitted by the human body. Which of the following statements is true [CBSE PMT 2003] |
| A. | The radiation is emitted only during the day |
| B. | The radiation is emitted during the summers and absorbed during the winters |
| C. | The radiation emitted lies in the ultraviolet region and hence is not visible |
| D. | The radiation emitted is in the infra-red region |
| Answer» E. | |
| 3772. |
The energy supply being cut-off, an electric heater element cools down to the temperature of its surroundings, but it will not cool further because [CPMT 2001] |
| A. | Supply is cut off |
| B. | It is made of metal |
| C. | Surroundings are radiating |
| D. | Element & surroundings have same temp. |
| Answer» E. | |
| 3773. |
Heat travels through vacuum by [AIIMS 1998; CPMT 2003] |
| A. | Conduction |
| B. | Convection |
| C. | Radiation |
| D. | Both (a) and (b) |
| Answer» D. Both (a) and (b) | |
| 3774. |
A thermos flask is polished well [AFMC 1996] |
| A. | To make attractive |
| B. | For shining |
| C. | To absorb all radiations from outside |
| D. | To reflect all radiations from outside |
| Answer» E. | |
| 3775. |
Which of the following law states that ?good absorbers of heat are good emitters? [Orissa JEE 2005] |
| A. | Stefan?s law |
| B. | Kirchoff?s law |
| C. | Planck?s law |
| D. | Wein?s law |
| Answer» C. Planck?s law | |
| 3776. |
Which of the following is the correct device for the detection of thermal radiation [Manipal MEE 1995, UPSEAT 2000] |
| A. | Constant volume thermometer |
| B. | Liquid-in-glass thermometer |
| C. | Six's maximum and minimum thermometer |
| D. | Thermopile |
| Answer» E. | |
| 3777. |
Which of the following statement is correct [RPMT 2001] |
| A. | A good absorber is a bad emitter |
| B. | Everybody absorbs and emits radiations at every temperature |
| C. | The energy of radiations emitted from a black body is same for all wavelengths |
| D. | The law showing the relation of temperatures with the wavelength of maximum emission from an ideal black body is Plank?s law |
| Answer» E. | |
| 3778. |
A piece of blue glass heated to a high temperature and a piece of red glass at room temperature, are taken inside a dimly lit room then [KCET 2005] |
| A. | The blue piece will look blue and red will look as usual |
| B. | Red look brighter red and blue look ordinary blue |
| C. | Blue shines like brighter red compared to the red piece |
| D. | Both the pieces will look equally red. |
| Answer» D. Both the pieces will look equally red. | |
| 3779. |
Which of the prism is used to see infra-red spectrum of light [RPMT 2000] |
| A. | Rock-salt |
| B. | Nicol |
| C. | Flint |
| D. | Crown |
| Answer» B. Nicol | |
| 3780. |
An ideal black body at room temperature is thrown into a furnace. It is observed that [IIT-JEE (Screening) 2002] |
| A. | Initially it is the darkest body and at later times the brightest |
| B. | It is the darkest body at all times |
| C. | It cannot be distinguished at all times |
| D. | Initially it is the darkest body and at later times it cannot be distinguished |
| Answer» B. It is the darkest body at all times | |
| 3781. |
Absorption co-efficient of an open window is... [KCET 2004] |
| A. | Zero |
| B. | 0.5 |
| C. | 1 |
| D. | 0.25 |
| Answer» D. 0.25 | |
| 3782. |
A body, which emits radiations of all possible wavelengths, is known as [CPMT 2001; Pb. PET 2002] |
| A. | Good conductor |
| B. | Partial radiator |
| C. | Absorber of photons |
| D. | Perfectly black-body |
| Answer» E. | |
| 3783. |
Which of the following is the example of ideal black body [AIEEE 2002; CBSE PMT 2002] |
| A. | Kajal |
| B. | Black board |
| C. | A pin hole in a box |
| D. | None of these |
| Answer» D. None of these | |
| 3784. |
A hot body will radiate heat most rapidly if its surface is [UPSEAT 1999, 2000] |
| A. | White & polished |
| B. | White & rough |
| C. | Black & polished |
| D. | Black & rough |
| Answer» E. | |
| 3785. |
At a certain temperature for given wave length, the ratio of emissive power of a body to emissive power of black body in same circumstances is known as [RPMT 1997] |
| A. | Relative emissivity |
| B. | Emissivity |
| C. | Absorption coefficient |
| D. | Coefficient of reflection |
| Answer» C. Absorption coefficient | |
| 3786. |
In which process, the rate of transfer of heat is maximum [EAMCET 1977; MP PMT 1994; MH CET 2001] |
| A. | Conduction |
| B. | Convection |
| C. | Radiation |
| D. | In all these, heat is transferred with the same velocity |
| Answer» D. In all these, heat is transferred with the same velocity | |
| 3787. |
When red glass is heated in dark room it will seem [RPET 2000] |
| A. | Green |
| B. | Purple |
| C. | Black |
| D. | Yellow |
| Answer» B. Purple | |
| 3788. |
There is a black spot on a body. If the body is heated and carried in dark room then it glows more. This can be explained on the basis of [RPET 2000] |
| A. | Newton?s law of cooling |
| B. | Wien?s law |
| C. | Kirchoff?s law |
| D. | Stefan?s |
| Answer» D. Stefan?s | |
| 3789. |
The cause of Fraunhoffer lines is [RPMT 1996; EAMCET 2001] |
| A. | Reflection of radiations by chromosphere |
| B. | Absorption of radiations by chromosphere |
| C. | Emission of radiations by chromosphere |
| D. | Transmission of radiations by chromosphere |
| Answer» C. Emission of radiations by chromosphere | |
| 3790. |
There is a rough black spot on a polished metallic plate. It is heated upto 1400 K approximately and then at once taken in a dark room. Which of the following statements is true [NCERT 1984; CPMT 1998] |
| A. | In comparison with the plate, the spot will shine more |
| B. | In camparison with the plate, the spot will appear more black |
| C. | The spot and the plate will be equally bright |
| D. | The plate and the black spot can not be seen in the dark room |
| Answer» B. In camparison with the plate, the spot will appear more black | |
| 3791. |
In rainy season, on a clear night the black seat of a bicycle becomes wet because |
| A. | It absorbs water vapour |
| B. | Black seat is good absorber of heat |
| C. | Black seat is good radiator of heat energy |
| D. | None of the above |
| Answer» D. None of the above | |
| 3792. |
Distribution of energy in the spectrum of a black body can be correctly represented by [MP PMT 1989] |
| A. | Wien's law |
| B. | Stefan's law |
| C. | Planck's law |
| D. | Kirchhoff's law |
| Answer» D. Kirchhoff's law | |
| 3793. |
When \[p\]calories of heat is given to a body, it absorbs \[q\] calories; then the absorbtion power of body will be |
| A. | \[p/q\] |
| B. | \[q/p\] |
| C. | \[{{p}^{2}}/{{q}^{2}}\] |
| D. | \[{{q}^{2}}/{{p}^{2}}\] |
| Answer» C. \[{{p}^{2}}/{{q}^{2}}\] | |
| 3794. |
If between wavelength \[\lambda \]and \[\lambda +d\lambda \], \[{{e}_{\lambda }}\]and \[{{a}_{\lambda }}\] be the emissive and absorptive powers of a body and \[{{E}_{\lambda }}\] be the emissive power of a perfectly black body, then according to Kirchoff's law, which is true [RPMT 1998; MP PET 1991] |
| A. | \[{{e}_{\lambda }}={{a}_{\lambda }}={{E}_{\lambda }}\] |
| B. | \[{{e}_{\lambda }}{{E}_{\lambda }}={{a}_{\lambda }}\] |
| C. | \[{{e}_{\lambda }}={{a}_{\lambda }}{{E}_{\lambda }}\] |
| D. | \[{{e}_{\lambda }}{{a}_{\lambda }}{{E}_{\lambda }}\]= constant |
| Answer» D. \[{{e}_{\lambda }}{{a}_{\lambda }}{{E}_{\lambda }}\]= constant | |
| 3795. |
The velocity of heat radiation in vacuum is [EAMCET 1982; KCET 1998] |
| A. | Equal to that of light |
| B. | Less than that of light |
| C. | Greater than that of light |
| D. | Equal to that of sound |
| Answer» B. Less than that of light | |
| 3796. |
Which of the following statements is wrong [BCECE 2001] |
| A. | Rough surfaces are better radiators than smooth surface |
| B. | Highly polished mirror like surfaces are very good radiators |
| C. | Black surfaces are better absorbers than white ones |
| D. | Black surfaces are better radiators than white |
| Answer» C. Black surfaces are better absorbers than white ones | |
| 3797. |
As compared to the person with white skin, the person with black skin will experience [CPMT 1988] |
| A. | Less heat and more cold |
| B. | More heat and more cold |
| C. | More heat and less cold |
| D. | Less heat and less cold |
| Answer» C. More heat and less cold | |
| 3798. |
Relation between emissivity \[e\] and absorptive power \[a\] is (for black body) |
| A. | \[e=a\] |
| B. | \[e=\frac{1}{a}\] |
| C. | \[e={{a}^{2}}\] |
| D. | \[a={{e}^{2}}\] |
| Answer» B. \[e=\frac{1}{a}\] | |
| 3799. |
Certain substance emits only the wavelengths \[{{\lambda }_{1}},\ {{\lambda }_{2}},\ {{\lambda }_{3}}\] and \[{{\lambda }_{4}}\] when it is at a high temperature. When this substance is at a colder temperature, it will absorb only the following wavelengths [MP PET 1990] |
| A. | \[{{\lambda }_{1}}\] |
| B. | \[{{\lambda }_{2}}\] |
| C. | \[{{\lambda }_{1}}\] and \[{{\lambda }_{2}}\] |
| D. | \[{{\lambda }_{1}},\ {{\lambda }_{2}},\ {{\lambda }_{3}}\] and \[{{\lambda }_{4}}\] |
| Answer» E. | |
| 3800. |
Good absorbers of heat are [J & K CET 2002] |
| A. | Poor emitters |
| B. | Non-emitters |
| C. | Good emitters |
| D. | Highly polished |
| Answer» D. Highly polished | |