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MCQOPTIONS
This section includes 11242 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.
| 1051. |
Pressure exerted by 1 mole of methane in a 0.25 litre container at 300K using vander Waal's equation (given \[1=2.253\,atm\,{{l}^{2}}\,mo{{l}^{-2}},\,b=0.0428\,lit\,mo{{l}^{-1}})\] is [Orissa JEE 2005] |
| A. | 82.82 atm |
| B. | 152.51 atm |
| C. | 190.52 atm |
| D. | 70.52 atm |
| Answer» B. 152.51 atm | |
| 1052. |
In van der Waal?s equation of state of the gas law, the constant ?\[b\]? is a measure of [AIEEE 2004] |
| A. | Volume occupied by the molecules |
| B. | Intermolecular attraction |
| C. | Intermolecular repulsions |
| D. | Intermolecular collisions per unit volume |
| Answer» B. Intermolecular attraction | |
| 1053. |
Gases deviate from the ideal gas behaviour because their molecules [NCERT 1981] |
| A. | Possess negligible volume |
| B. | Have forces of attraction between them |
| C. | Are polyatomic |
| D. | Are not attracted to one another |
| Answer» C. Are polyatomic | |
| 1054. |
When helium is allowed to expand into vacuum, heating effect is observed. Its reason is that [CPMT 1987] |
| A. | Helium is an ideal gas |
| B. | Helium is an inert gas |
| C. | The inversion temperature of helium is very low |
| D. | The boiling point of helium is the lowest among the elements |
| Answer» D. The boiling point of helium is the lowest among the elements | |
| 1055. |
At low pressure, the Vander Waal's equation is reduced to |
| A. | \[Z=\frac{p{{V}_{m}}}{RT}=1-\frac{ap}{RT}\] |
| B. | \[Z=\frac{p{{V}_{m}}}{RT}=1+\frac{b}{RT}p\] |
| C. | \[p{{V}_{m}}=RT\] |
| D. | \[Z=\frac{p{{V}_{m}}}{RT}=1-\frac{a}{RT}\] |
| Answer» B. \[Z=\frac{p{{V}_{m}}}{RT}=1+\frac{b}{RT}p\] | |
| 1056. |
The temperature at which real gases obey the ideal gas laws over a wide range of pressure is called [AFMC 1993; IIT 1981, 94] |
| A. | Critical temperature |
| B. | Boyle temperature |
| C. | Inversion temperature |
| D. | Reduced temperature |
| Answer» C. Inversion temperature | |
| 1057. |
A real gas most closely approaches the behaviour of an ideal gas at [KCET 1992] |
| A. | 15 atm and 200 K |
| B. | 1 atm and 273 K |
| C. | 0.5 atm and 500 K |
| D. | 15 atm and 500 K |
| Answer» D. 15 atm and 500 K | |
| 1058. |
A gas is said to behave like an ideal gas when the relation \[PV/T=\text{constant}\]. When do you expect a real gas to behave like an ideal gas [IIT 1999; CBSE PMT 1990; CPMT 1991] |
| A. | When the temperature is low |
| B. | When both the temperature and pressure are low |
| C. | When both the temperature and pressure are high |
| D. | When the temperature is high and pressure is low |
| Answer» E. | |
| 1059. |
The compressibility factor for an ideal gas is [IIT 1997] |
| A. | 1.5 |
| B. | 1.0 |
| C. | 2.0 |
| D. | ¥ |
| Answer» C. 2.0 | |
| 1060. |
The Vander Waal's equation reduces itself to the ideal gas equation at [Kerala MEE 2001; CBSE PMT 2002] |
| A. | High pressure and low temperature |
| B. | Low pressure and low temperature |
| C. | Low pressure and high temperature |
| D. | High pressure and high temperature |
| Answer» D. High pressure and high temperature | |
| 1061. |
Gas deviates from ideal gas nature because molecules [CPMT 1996] |
| A. | Are colourless |
| B. | Attract each other |
| C. | Contain covalent bond |
| D. | Show Brownian movement |
| Answer» C. Contain covalent bond | |
| 1062. |
What is the half-life of a radioactive substance if 75% of a given amount of the substance disintegrates in 30 minutes |
| A. | 7.5 minutes |
| B. | 25 minutes |
| C. | 20 minutes |
| D. | 15 minutes |
| Answer» E. | |
| 1063. |
If 8.0 g of a radioactive substance has a half-life of 10 hrs., the half-life of 2.0 g of the same substance is [J & K 2005] |
| A. | 2.6 hr |
| B. | 5 hr |
| C. | 10 hr |
| D. | 40 hr |
| Answer» D. 40 hr | |
| 1064. |
A radioactive sample is emitting 64 times radiations than nonhazardous limit. if its half-life is 2 hours, after what time it becomes non-hazardous [DPMT 2005] |
| A. | 16 hr |
| B. | 12 hr |
| C. | 8 hr |
| D. | 4 hr |
| Answer» C. 8 hr | |
| 1065. |
A radioactive substance takes 20 min to decay 25%. How much time will be taken to decay 75% [Orissa JEE 2005] |
| A. | 96.4 min |
| B. | 68 min |
| C. | 964 min |
| D. | 680 min |
| Answer» B. 68 min | |
| 1066. |
\[{{T}_{1/2}}\] of \[{{C}^{14}}\] isotope is 5770 years. time after which 72% of isotope left is [Orissa JEE 2005] |
| A. | 2740 years |
| B. | 274 years |
| C. | 2780 years |
| D. | 278 years |
| Answer» B. 274 years | |
| 1067. |
The radioactive decay of \[_{35}{{X}^{88}}\] by a beta emission produces an unstable nucleus which spontaneously emits a neutron. The final product is [MNR 1995; CBSE 2001] |
| A. | \[_{37}{{X}^{88}}\] |
| B. | \[_{35}{{Y}^{89}}\] |
| C. | \[_{34}{{Z}^{88}}\] |
| D. | \[_{36}{{W}^{87}}\] |
| Answer» E. | |
| 1068. |
Rate constant for a reaction is \[\lambda \]. Average life is representative by [Orissa JEE 2004] |
| A. | \[1/\lambda \] |
| B. | \[\text{In}2/\lambda \] |
| C. | \[\frac{\lambda }{\sqrt{2}}\] |
| D. | \[\frac{0.693}{\lambda }\] |
| Answer» B. \[\text{In}2/\lambda \] | |
| 1069. |
In the given reaction, \[_{92}{{U}^{235}}\xrightarrow{-\alpha }(A)\xrightarrow{-\beta }(B)\xrightarrow{-\beta }(C)\] isotope are [Pb. CET 2000] |
| A. | A and C |
| B. | \[_{92}{{U}^{235}}\]and C |
| C. | A and B |
| D. | A, B and C |
| Answer» C. A and B | |
| 1070. |
An artificial radioactive isotope gave \[_{7}^{14}N\]after two successive \[\beta -\]particle emissions. The number of neutrons in the parent nucleus must be [KCET 2004] |
| A. | 9 |
| B. | 14 |
| C. | 5 |
| D. | 7 |
| Answer» B. 14 | |
| 1071. |
The half-life of a radioisotope is four hours. If the initial mass of the isotope was 200 g, the mass remaining after 24 hours undecayed is [AIEEE 2004] |
| A. | 3.125 g |
| B. | 2.084 g |
| C. | 1.042 g |
| D. | 4.167 g |
| Answer» B. 2.084 g | |
| 1072. |
Amount of \[_{53}{{I}^{128}}({{t}_{1/2}}=25\ \min )\] left after 75 minutes is [DCE 2002] |
| A. | \[1/6\] |
| B. | \[1/4\] |
| C. | \[1/8\] |
| D. | \[1/9\] |
| Answer» D. \[1/9\] | |
| 1073. |
If the disintegration constant is \[6.93\times {{10}^{-6}},\] then half-life of \[_{6}{{C}^{14}}\] will be [KCET 2001] |
| A. | \[{{10}^{2}}\]yrs |
| B. | \[{{10}^{3}}\]yrs |
| C. | \[{{10}^{4}}\]yrs |
| D. | \[{{10}^{5}}\]yrs |
| Answer» E. | |
| 1074. |
If 8.0 of a radioactive isotope has a half-life of 10 hrs. The half-life of 2.0 g of the same substance is [UPSEAT 2001] |
| A. | 2.5 hrs. |
| B. | 5 hrs. |
| C. | 10 hrs. |
| D. | 40 hrs. |
| Answer» D. 40 hrs. | |
| 1075. |
A radioactive element decays at such a rate that after 15 minutes only 1/10 of the original amount is left. How many more minutes will be needed when only 1/100 of the original amount will be left |
| A. | 1.5 minutes |
| B. | 15.0 mintues |
| C. | 16.5 minutes |
| D. | 30 minutes |
| Answer» E. | |
| 1076. |
A certain nuclide has a half-life of 25 minutes. If one starts with 100 g of it, how much of it will remain at the end of 100 minutes [DPMT 1982] |
| A. | 1.0 g |
| B. | 4.0 g |
| C. | 6.25 g |
| D. | 12.50 g |
| Answer» D. 12.50 g | |
| 1077. |
The activity of radio isotope changes with [MNR 1986] |
| A. | Temperature |
| B. | Pressure |
| C. | Chemical environment |
| D. | None of these |
| Answer» E. | |
| 1078. |
The half-life of a radioactive element depends upon [EAMCET 1980] |
| A. | The amount of the element |
| B. | The temperature |
| C. | The pressure |
| D. | None of these |
| Answer» E. | |
| 1079. |
Radioactive decay is a [MP PMT 1989, 97] |
| A. | Second order reaction |
| B. | First order reation |
| C. | Zero order reaction |
| D. | Third order reaction |
| Answer» C. Zero order reaction | |
| 1080. |
Given that a radioactive species decays according to exponential law \[N={{N}_{0}}{{e}^{-\lambda t}}\]. The half-life of the species is [Kerala (Med.) 2003] |
| A. | \[\lambda \] |
| B. | \[No\] |
| C. | \[\lambda /\ln 2\] |
| D. | \[\ln 2/\lambda \] |
| Answer» E. | |
| 1081. |
Half-life of a radioactive disintegration (A \[\to \]B) having rate constant \[231\,{{\sec }^{-1}}\] is [CPMT 1988] |
| A. | \[3.0\times {{10}^{-2}}\] sec |
| B. | \[3.0\times {{10}^{-3}}\] sec |
| C. | \[3.3\times {{10}^{-2}}\] sec |
| D. | \[3.3\times {{10}^{-3}}\] sec |
| Answer» C. \[3.3\times {{10}^{-2}}\] sec | |
| 1082. |
Tritium undergoes radioactive decay giving [CPMT 1976; NCERT 1978] |
| A. | \[\alpha \]-particles |
| B. | \[\beta \]-particles |
| C. | Neutrons |
| D. | None of these |
| Answer» C. Neutrons | |
| 1083. |
\[1.0g\] of a radioactive isotope was found to reduce to \[125\,mg\] after 24 hours. The half-life of the isotope is [MP PET 1996] |
| A. | 8 hours |
| B. | 24 hours |
| C. | 6 hours |
| D. | 4 hours |
| Answer» B. 24 hours | |
| 1084. |
87.5% decomposition of a radioactive substance complete in 3 hours. What is the half-life of that substance [MP PMT 2003] |
| A. | 2 hours |
| B. | 3 hours |
| C. | 90 minutes |
| D. | 1 hours |
| Answer» E. | |
| 1085. |
The decay of a radioactive element follows first order kinetics, as a result [NCERT 1982] |
| A. | Half-life period = constant \[/k\], where \[k\] is the decay constant |
| B. | Rate of decay is independent of temperature |
| C. | Rate can be changed by changing chemical conditions |
| D. | The element will be completely transformed into a new element after expiry of two half-life period |
| Answer» B. Rate of decay is independent of temperature | |
| 1086. |
Half-life of a radioactive substance which disintegrates by 75 % in 60 minutes, will be [MP PMT 2002] |
| A. | 120 min |
| B. | 30 min |
| C. | 45 min |
| D. | 20 min |
| Answer» C. 45 min | |
| 1087. |
The radioactivity due to \[{{C}^{14}}\] isotope (half-life 6000 years) of a sample of wood from an ancient tomb was found to be nearly half that of fresh wood, the tomb is therefore about [NCERT 1980, 81; MP PET 1989] |
| A. | 3000 years old |
| B. | 6000 years old |
| C. | 9000 years old |
| D. | 1200 years old |
| Answer» C. 9000 years old | |
| 1088. |
A radioactive element has half-life of one day. After three days, the amount of the element left will be [MNR 1985; UPSEAT 2000, 01; MH CET 2002] |
| A. | 1/2 of the original amount |
| B. | 1/4 of the original amount |
| C. | 1/8 of the original amount |
| D. | 1/16 of the original amount |
| Answer» D. 1/16 of the original amount | |
| 1089. |
In the case of a radio isotope the value of \[{{T}_{1/2}}\] and l are identical in magnitude. The value is [KCET 2002] |
| A. | \[0.693\] |
| B. | \[{{(0.693)}^{1/2}}\] |
| C. | \[1/0.693\] |
| D. | \[{{(0.693)}^{2}}\] |
| Answer» C. \[1/0.693\] | |
| 1090. |
The half-life of a radioactive element is 6 months. The time taken to reduce its original concentration to its 1/16 value is [MP PET 1991] |
| A. | 1 year |
| B. | 16 years |
| C. | 2 years |
| D. | 8 years |
| Answer» D. 8 years | |
| 1091. |
Radium has atomic weight 226 and a half-life of 1600 years. The number of disintegrations produced per second from \[1gm\] are [BHU 1990] |
| A. | \[4.8\times {{10}^{10}}\] |
| B. | \[9.2\times {{10}^{6}}\] |
| C. | \[3.7\times {{10}^{10}}\] |
| D. | Zero |
| Answer» D. Zero | |
| 1092. |
The half-life of \[_{92}{{U}^{238}}\] is \[4.5\times {{10}^{9}}\] years. After how many years, the amount of \[_{92}{{U}^{238}}\] will be reduced to half of its present amount [CPMT 1990; MP PET 1999] |
| A. | \[9.0\times {{10}^{9}}\] years |
| B. | \[13.5\times {{10}^{9}}\] years |
| C. | \[4.5\times {{10}^{9}}\] years |
| D. | \[4.5\times {{10}^{4.5}}\] years |
| Answer» D. \[4.5\times {{10}^{4.5}}\] years | |
| 1093. |
If \[2.0\,g\] of a radioactive isotope has a half-life of 20 hr, the half-life of \[0.5g\] of the same substance is [MP PMT 1990; MNR 1992] |
| A. | 20 hr |
| B. | 80 hr |
| C. | 5 hr |
| D. | 10 hr |
| Answer» B. 80 hr | |
| 1094. |
75% of the first order reaction was completed in 32 minutes. When was 50% of the reaction completed [MNR 1983; MP PET 1997; EAMCET 1998] |
| A. | 24 minutes |
| B. | 16 minutes |
| C. | 8 minutes |
| D. | 4 minutes |
| Answer» C. 8 minutes | |
| 1095. |
The half-life of the radio element \[_{83}B{{i}^{210}}\] is 5 days. Starting with 20 g of this isotope, the amount remaining after 15 days is [BHU 1987] |
| A. | 10 g |
| B. | 5 g |
| C. | 2.5 g |
| D. | 6.66 g |
| Answer» D. 6.66 g | |
| 1096. |
A substance of which one gram is taken, after half-life time what fraction of it is left ? [MADT Bihar 1983] |
| A. | \[\frac{1}{4}\] |
| B. | \[\frac{1}{8}\] |
| C. | \[\frac{1}{2}\] |
| D. | \[\frac{1}{32}\] |
| Answer» D. \[\frac{1}{32}\] | |
| 1097. |
For a radioactive substance with half-life period 500 years, the time for complete decay of 100 milligram of it would be [MADT Bihar 1984] |
| A. | 1000 years |
| B. | \[100\times 500\] years |
| C. | 500 years |
| D. | Infinite time |
| Answer» E. | |
| 1098. |
The half-life period of a radioactive element is 30 minutes. One sixteenth of the original quantity of the element will remain unchanged after [CPMT 1983; MP PMT 1994] |
| A. | 60 minutes |
| B. | 120 minutes |
| C. | 70 minutes |
| D. | 75 minutes |
| Answer» C. 70 minutes | |
| 1099. |
Half-life of a radioactive element is 100 yrs. The time in which it disintegrates to 50% of its mass, will be [MP PMT 1995] |
| A. | 50 yrs |
| B. | 200 yrs |
| C. | 100 yrs |
| D. | 25 yrs |
| Answer» D. 25 yrs | |
| 1100. |
\[C-14\] has a half-life of 5760 years. \[100mg\] of a sample containing \[C-14\] is reduced to \[25mg\] in [Bihar CEE 1992; AMU 2002; MHCET 1999] |
| A. | 11520 years |
| B. | 2880 years |
| C. | 1440 years |
| D. | 17280 years |
| Answer» B. 2880 years | |