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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.
| 6101. |
Two electric bulbs whose resistances are in the ratio of 1 : 2 are connected in series. The powers dissipated in them have the ratio [NCERT 1977] |
| A. | 1 : 2 |
| B. | 2 : 1 |
| C. | 1 : 1 |
| D. | 1 : 4 |
| Answer» B. 2 : 1 | |
| 6102. |
A wire when connected to 220V mains supply has power dissipation \[{{P}_{1}}\]. Now the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this case is \[{{P}_{2}}\]. Then \[{{P}_{2}}:{{P}_{1}}\] is [AIEEE 2002] |
| A. | 1 |
| B. | 4 |
| C. | 2 |
| D. | 3 |
| Answer» C. 2 | |
| 6103. |
n identical bulbs, each designed to draw a power p from a certain voltage supply, are joined in series across that supply. The total power which they will draw is [KCET 2002] |
| A. | \[p/{{n}^{2}}\] |
| B. | \[p/n\] |
| C. | \[p\] |
| D. | \[np\] |
| Answer» C. \[p\] | |
| 6104. |
Two electric bulbs rated \[{{P}_{1}}\] watt V volts and \[{{P}_{2}}\] watt V volts are connected in parallel and V volts are applied to it. The total power will be [MP PMT 2001; MP PET 2002] |
| A. | \[{{P}_{1}}+{{P}_{2}}watt\] |
| B. | \[\sqrt{{{P}_{1}}{{P}_{2}}}\]watt |
| C. | \[\frac{{{P}_{1}}{{P}_{2}}}{{{P}_{1}}+{{P}_{2}}}watt\] |
| D. | \[\frac{{{P}_{1}}+{{P}_{2}}}{{{P}_{1}}{{P}_{2}}}watt\] |
| Answer» B. \[\sqrt{{{P}_{1}}{{P}_{2}}}\]watt | |
| 6105. |
The amount of heat produced in a resistor when a current is passed through it can be found using [Kerala PET 2001] |
| A. | Faraday?s Law |
| B. | Kirchhoff?s Law |
| C. | Laplace?s Law |
| D. | Joule?s Law |
| Answer» E. | |
| 6106. |
An external resistance R is connected to a battery of e.m.f. V and internal resistance r. The joule heat produced in resistor R is maximum when R is equal to [MP PET 2001] |
| A. | r |
| B. | \[\frac{r}{2}\] |
| C. | 2r |
| D. | Infinitely large |
| Answer» B. \[\frac{r}{2}\] | |
| 6107. |
An electric kettle has two heating coils. When one coil is used, water in the kettle boils in 5 minutes, while when second coil is used, same water boils in 10 minutes. If the two coils, connected in parallel are used simultaneously, the same water will boil in time [MP PET 2001] |
| A. | 3 min 20 sec |
| B. | 5 min |
| C. | 7 min 30 sec |
| D. | 2 min 30 sec |
| Answer» B. 5 min | |
| 6108. |
Three bulbs of 40W, 60W and 100W are arranged in series with 220V. Which bulb has minimum resistance [AFMC 2001] |
| A. | 40W |
| B. | 60W |
| C. | 100W |
| D. | Equal in all bulbs |
| Answer» D. Equal in all bulbs | |
| 6109. |
If two electric bulbs have 40W and 60W rating at \[220V\], then the ratio of their resistances will be [BHU 1999; KCET 2001] |
| A. | 3 : 2 |
| B. | 2 : 3 |
| C. | 3 : 4 |
| D. | 4 : 3 |
| Answer» B. 2 : 3 | |
| 6110. |
The mechanism of the heat produced in a conductor when an electric current flows through it, can be explained on the basis of |
| A. | Viscosity |
| B. | Friction |
| C. | Free electron theory |
| D. | Gauss's theorem |
| Answer» D. Gauss's theorem | |
| 6111. |
An ideal heat engine exhausting heat at \[{{77}^{o}}C\] is to have a 30% efficiency. It must take heat at [BCECE 2004] |
| A. | \[{{127}^{o}}C\] |
| B. | \[{{227}^{o}}C\] |
| C. | \[{{327}^{o}}C\] |
| D. | \[{{673}^{o}}C\] |
| Answer» C. \[{{327}^{o}}C\] | |
| 6112. |
An ideal gas heat engine operates in a Carnot's cycle between \[{{227}^{o}}C\] and \[{{127}^{o}}C\]. It absorbs 6 × 104 J at high temperature. The amount of heat converted into work is .... [KCET 2004] |
| A. | \[4.8\times {{10}^{4}}\,J\] |
| B. | \[3.5\times {{10}^{4}}\,J\] |
| C. | \[1.6\times {{10}^{4}}\,J\] |
| D. | \[1.2\times {{10}^{4}}\,J\] |
| Answer» E. | |
| 6113. |
In a cyclic process, work done by the system is [BHU 2002] |
| A. | Zero |
| B. | Equal to heat given to the system |
| C. | More than the heat given to system |
| D. | Independent of heat given to the system |
| Answer» C. More than the heat given to system | |
| 6114. |
Irreversible process is |
| A. | Adiabatic process |
| B. | Joule-Thomson expansion |
| C. | Ideal isothermal process |
| D. | None of the above |
| Answer» C. Ideal isothermal process | |
| 6115. |
In a cyclic process, the internal energy of the gas |
| A. | Increases |
| B. | Decreases |
| C. | Remains constant |
| D. | Becomes zero |
| Answer» D. Becomes zero | |
| 6116. |
Which of the following processes is reversible [CBSE PMT 2005] |
| A. | Transfer of heat by radiation |
| B. | Electrical heating of a nichrome wire |
| C. | Transfer of heat by conduction |
| D. | Isothermal compression |
| Answer» E. | |
| 6117. |
An ideal gas heat engine operates in Carnot cycle between 227°C and 127°C. It absorbs \[6\times {{10}^{4}}\] cals of heat at higher temperature. Amount of heat converted to work is [CBSE PMT 2005] |
| A. | \[2.4\times {{10}^{4}}\]cal |
| B. | \[6\times {{10}^{4}}\] cal |
| C. | \[1.2\times {{10}^{4}}\] cal |
| D. | \[4.8\times {{10}^{4}}\] cal |
| Answer» D. \[4.8\times {{10}^{4}}\] cal | |
| 6118. |
In a mechanical refrigerator, the low temperature coils are at a temperature of ? 23°C and the compressed gas in the condenser has a temperature of 27°C. The theoretical coefficient of performance is [UPSEAT 2001] |
| A. | 5 |
| B. | 8 |
| C. | 6 |
| D. | 6.5 |
| Answer» B. 8 | |
| 6119. |
An engine is supposed to operate between two reservoirs at temperature 727°C and 227°C. The maximum possible efficiency of such an engine is [UPSEAT 2005] |
| A. | 1/2 |
| B. | 1/4 |
| C. | 3/4 |
| D. | 1 |
| Answer» B. 1/4 | |
| 6120. |
An ideal refrigerator has a freezer at a temperature of \[-13{}^\circ C.\] The coefficient of performance of the engine is 5. The temperature of the air (to which heat is rejected) will be [BHU 2000; CPMT 2002] |
| A. | 325°C |
| B. | 325K |
| C. | 39°C |
| D. | 320°C |
| Answer» D. 320°C | |
| 6121. |
If the door of a refrigerator is kept open, then which of the following is true [DPMT 2001; BHU 2001; JIPMER 2002; AIEEE 2002; CPMT 2003] |
| A. | Room is cooled |
| B. | Room is heated |
| C. | Room is either cooled or heated |
| D. | Room is neither cooled nor heated |
| Answer» C. Room is either cooled or heated | |
| 6122. |
An ideal heat engine working between temperature T1 and T2 has an efficiency h, the new efficiency if both the source and sink temperature are doubled, will be [DPMT 2000] |
| A. | \[\frac{\eta }{2}\] |
| B. | \[\eta \] |
| C. | \[2\eta \] |
| D. | \[3\eta \] |
| Answer» C. \[2\eta \] | |
| 6123. |
The first operation involved in a Carnot cycle is [AFMC 1998] |
| A. | Isothermal expansion |
| B. | Adiabatic expansion |
| C. | Isothermal compression |
| D. | Adiabatic compression |
| Answer» B. Adiabatic expansion | |
| 6124. |
The efficiency of Carnot engine when source temperature is T1 and sink temperature is T2 will be [DCE 2000] |
| A. | \[\frac{{{T}_{1}}-{{T}_{2}}}{{{T}_{1}}}\] |
| B. | \[\frac{{{T}_{2}}-{{T}_{1}}}{{{T}_{2}}}\] |
| C. | \[\frac{{{T}_{1}}-{{T}_{2}}}{{{T}_{2}}}\] |
| D. | \[\frac{{{T}_{1}}}{{{T}_{2}}}\] |
| Answer» B. \[\frac{{{T}_{2}}-{{T}_{1}}}{{{T}_{2}}}\] | |
| 6125. |
A Carnot engine takes \[3\times {{10}^{6}}\,cal\]. of heat from a reservoir at 627°C, and gives it to a sink at 27°C. The work done by the engine is [AIEEE 2003] |
| A. | \[4.2\times {{10}^{6}}J\] |
| B. | \[8.4\times {{10}^{6}}J\] |
| C. | \[16.8\times {{10}^{6}}J\] |
| D. | Zero |
| Answer» C. \[16.8\times {{10}^{6}}J\] | |
| 6126. |
?Heat cannot by itself flow from a body at lower temperature to a body at higher temperature? is a statement or consequence of [AIEEE 2003, EAMCET (Med.) 2003] |
| A. | Second law of thermodynamics |
| B. | Conservation of momentum |
| C. | Conservation of mass |
| D. | First law of thermodynamics |
| Answer» B. Conservation of momentum | |
| 6127. |
Even Carnot engine cannot give 100% efficiency because we cannot [AIEEE 2002] |
| A. | Prevent radiation |
| B. | Find ideal sources |
| C. | Reach absolute zero temperature |
| D. | Eliminate friction |
| Answer» D. Eliminate friction | |
| 6128. |
Efficiency of a Carnot engine is 50% when temperature of outlet is 500 K. In order to increase efficiency up to 60% keeping temperature of intake the same what is temperature of outlet [CBSE PMT 2002] |
| A. | 200 K |
| B. | 400 K |
| C. | 600 K |
| D. | 800 K |
| Answer» C. 600 K | |
| 6129. |
A Carnot?s engine is made to work between 200°C and 0°C first and then between 0°C and ?200°C. The ratio of efficiencies of the engine in the two cases is [KCET 2002] |
| A. | 1.73 : 1 |
| B. | 1 : 1.73 |
| C. | 1 : 1 |
| D. | 1 : 2 |
| Answer» C. 1 : 1 | |
| 6130. |
A scientist says that the efficiency of his heat engine which operates at source temperature 127°C and sink temperature 27°C is 26%, then [CBSE PMT 2001] |
| A. | It is impossible |
| B. | It is possible but less probable |
| C. | It is quite probable |
| D. | Data are incomplete |
| Answer» B. It is possible but less probable | |
| 6131. |
The coefficient of performance of a Carnot refrigerator working between \[{{30}^{o}}C\]and \[{{0}^{o}}C\] is [UPSEAT 2002] |
| A. | 10 |
| B. | 1 |
| C. | 9 |
| D. | 0 |
| Answer» D. 0 | |
| 6132. |
A carnot engine has the same efficiency between 800 K to 500 K and x K to 600 K. The value of x is [Pb. PMT 1996; CPMT 1996] |
| A. | 1000 K |
| B. | 960 K |
| C. | 846 K |
| D. | 754 K |
| Answer» C. 846 K | |
| 6133. |
A measure of the degree of disorder of a system is known as [Pb. PET 1997; MH CET 1999] |
| A. | Isobaric |
| B. | Isotropy |
| C. | Enthalpy |
| D. | Entropy |
| Answer» E. | |
| 6134. |
A Carnot engine operates between \[{{227}^{o}}C\] and \[{{27}^{o}}C.\] Efficiency of the engine will be [DCE 1999; BHU 2004] |
| A. | \[\frac{1}{3}\] |
| B. | \[\frac{2}{5}\] |
| C. | \[\frac{3}{4}\] |
| D. | \[\frac{3}{5}\] |
| Answer» C. \[\frac{3}{4}\] | |
| 6135. |
The efficiency of Carnot's engine operating between reservoirs, maintained at temperatures \[{{27}^{o}}C\] and \[-{{123}^{o}}C,\] is [DPMT 2002, 03; BVP 2004] |
| A. | 50% |
| B. | 24% |
| C. | 0.75% |
| D. | 0.4% |
| Answer» B. 24% | |
| 6136. |
In a Carnot engine, when \[{{T}_{2}}={{0}^{o}}C\] and \[{{T}_{1}}={{200}^{o}}C,\] its efficiency is \[{{\eta }_{1}}\]and when \[{{T}_{1}}=0{{\,}^{o}}C\] and \[{{T}_{2}}=-200{{\,}^{o}}C\], Its efficiency is \[{{\eta }_{2}}\], then what is \[{{\eta }_{1}}/{{\eta }_{2}}\] [DCE 2004] |
| A. | 0.577 |
| B. | 0.733 |
| C. | 0.638 |
| D. | Cannot be calculated |
| Answer» B. 0.733 | |
| 6137. |
The temperature of reservoir of Carnot's engine operating with an efficiency of 70% is 1000K. The temperature of its sink is [DCE 2003] |
| A. | 300 K |
| B. | 400 K |
| C. | 500 K |
| D. | 700 K |
| Answer» B. 400 K | |
| 6138. |
The temperature of sink of Carnot engine is \[{{27}^{o}}C\]. Efficiency of engine is 25%. Then temperature of source is [DCE 2002; CPMT 2002] |
| A. | \[{{227}^{o}}C\] |
| B. | \[{{327}^{o}}C\] |
| C. | \[{{127}^{o}}C\] |
| D. | \[{{27}^{o}}C\] |
| Answer» D. \[{{27}^{o}}C\] | |
| 6139. |
A Carnot engine absorbs an amount Q of heat from a reservoir at an abosolute temperature T and rejects heat to a sink at a temperature of T/3. The amount of heat rejected is [UPSEAT 2004] |
| A. | Q / 4 |
| B. | Q / 3 |
| C. | Q / 2 |
| D. | 2Q / 3 |
| Answer» C. Q / 2 | |
| 6140. |
A Carnot's engine used first an ideal monoatomic gas then an ideal diatomic gas. If the source and sink temperature are \[{{411}^{o}}C\] and \[{{69}^{o}}C\] respectively and the engine extracts 1000 J of heat in each cycle, then area enclosed by the PV diagram is [Pb. PET 2002] |
| A. | 100 J |
| B. | 300 J |
| C. | 500 J |
| D. | 700 J |
| Answer» D. 700 J | |
| 6141. |
Efficiency of Carnot engine is 100% if [Pb. PET 2000] |
| A. | \[{{T}_{2}}=273\,\,K\] |
| B. | \[{{T}_{2}}=0\,\,K\] |
| C. | \[{{T}_{1}}=273\,\,K\] |
| D. | \[{{T}_{1}}=0\,\,K\] |
| Answer» C. \[{{T}_{1}}=273\,\,K\] | |
| 6142. |
A Carnot engine working between \[300\,K\] and 600K has work output of 800 J per cycle. What is amount of heat energy supplied to the engine from source per cycle [DPMT 1999; Pb. PMT 2002, 05; Kerala PMT 2004] |
| A. | 1800 J/cycle |
| B. | 1000 J/cycle |
| C. | 2000 J/cycle |
| D. | 1600 J/cycle |
| Answer» E. | |
| 6143. |
In the circuit shown in the figure, the current flowing in \[2\,\Omega \] resistance [CPMT 1989; MP PMT 2004] |
| A. | 1.4 A |
| B. | 1.2 A |
| C. | 0.4 A |
| D. | 1.0 A |
| Answer» E. | |
| 6144. |
In the circuit shown in the adjoining figure, the current between B and D is zero, the unknown resistance is of [CPMT 1986] |
| A. | \[4\,\Omega \] |
| B. | \[2\,\Omega \] |
| C. | \[3\,\Omega \] |
| D. | e.m.f. of a cell is required to find the value of X |
| Answer» C. \[3\,\Omega \] | |
| 6145. |
A series combination of two resistors 1 W each is connected to a 12 V battery of internal resistance 0.4 W. The current flowing through it will be [MH CET (Med.) 1999] |
| A. | 3.5 A |
| B. | 5 A |
| C. | 6 A |
| D. | 10 A |
| Answer» C. 6 A | |
| 6146. |
In the circuit shown below, The reading of the voltmeter V is [MP PET 2003] |
| A. | 12 V |
| B. | 8 V |
| C. | 20 V |
| D. | 16 V |
| Answer» B. 8 V | |
| 6147. |
The potential difference between point A & B is [BHU 2003; CPMT 2004; MP PMT 2005] |
| A. | \[\frac{20}{7}\,\,V\] |
| B. | \[\frac{40}{7}\,\,V\] |
| C. | \[\frac{10}{7}\,\,V\] |
| D. | 0 |
| Answer» E. | |
| 6148. |
Find the equivalent resistance between the points a and b [BHU 2003; CPMT 2004] |
| A. | 2 W |
| B. | 4 W |
| C. | 8 W |
| D. | 16 W |
| Answer» C. 8 W | |
| 6149. |
A 3volt battery with negligible internal resistance is connected in a circuit as shown in the figure. The current I, in the circuit will be [AIEEE 2003] |
| A. | 1/3 A |
| B. | 1 A |
| C. | 1.5 A |
| D. | 2 A |
| Answer» D. 2 A | |
| 6150. |
Three unequal resistors in parallel are equivalent to a resistance 1 ohm. If two of them are in the ratio 1 : 2 and if no resistance value is fractional, the largest of the three resistances in ohms is [EAMCET 2003] |
| A. | 4 |
| B. | 6 |
| C. | 8 |
| D. | 12 |
| Answer» C. 8 | |