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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.
| 1101. |
In the radioactive decay \[_{92}{{X}^{232}}\to {{\,}_{89}}{{Y}^{220}}\], how many \[\alpha \] and \[\beta \]- particles are ejected from \[X\] to form \[Y\] [CBSE 1999] |
| A. | \[3\alpha \] and \[3\beta \] |
| B. | \[5\alpha \] and \[3\beta \] |
| C. | \[3\alpha \] and \[5\beta \] |
| D. | \[5\alpha \] and \[5\beta \] |
| Answer» B. \[5\alpha \] and \[3\beta \] | |
| 1102. |
The half-life of \[C{{o}^{60}}\] is 7 years. If one \[gm\] of it decays, the amount of the substance remaining after 28 years is [EAMCET 1992] |
| A. | \[0.25\,gm\] |
| B. | \[0.125\,gm\] |
| C. | \[0.0625\,gm\] |
| D. | \[0.50\,gm\] |
| Answer» D. \[0.50\,gm\] | |
| 1103. |
Half-life of a radioactive substance is 120 days. After 480 days, 4 gm will be reduced to [EAMCET 1993] |
| A. | 2 |
| B. | 1 |
| C. | 0.5 |
| D. | 0.25 |
| Answer» E. | |
| 1104. |
The half-life of radium (226) is 1620 years. The time taken to convert 10 grams of radium to 1.25 grams is [MP PET 1994; UPSEAT 2001] |
| A. | 810 years |
| B. | 1620 years |
| C. | 3240 years |
| D. | 4860 years |
| Answer» E. | |
| 1105. |
\[8gm\] of the radioactive isotope, cesium-137 were collected on February 1 and kept in a sealed tube. On July 1, it was found that only \[0.25gm\] of it remained. So the half-life period of the isotope is [KCET 1989] |
| A. | 37.5 days |
| B. | 30 days |
| C. | 25 days |
| D. | 50 days |
| Answer» C. 25 days | |
| 1106. |
If the half-life period of a first order reaction is 138.6 minutes, then the value of decay constant for the reaction will be [MH CET 1999] |
| A. | 5 minute?1 |
| B. | 0.5 minute?1 |
| C. | 0.05 minute?1 |
| D. | 0.005 minute?1 |
| Answer» E. | |
| 1107. |
The binding energy of \[_{8}{{O}^{16}}\] is 127 MeV. Its binding energy per neutron is [MH CET 1999] |
| A. | 0.794 MeV |
| B. | 1.5875 MeV |
| C. | 7.94 MeV |
| D. | 15.875 MeV |
| Answer» D. 15.875 MeV | |
| 1108. |
A radioactive isotope has a half-life of 10 days. If today \[125\,mg\]is left over, what was its original weight 40 days earlier [KCET 2005] |
| A. | 2g |
| B. | 600 mg |
| C. | 1 g |
| D. | 1.5 g |
| Answer» B. 600 mg | |
| 1109. |
The half-life of \[_{6}{{C}^{14}}\] if its K or \[\lambda \] is \[2.31\times {{10}^{-4}}\] is [BHU 1999] |
| A. | \[2\times {{10}^{2}}yrs\] |
| B. | \[3\times {{10}^{3}}yrs\] |
| C. | \[3.5\times {{10}^{4}}yrs\] |
| D. | \[4\times {{10}^{3}}yrs\] |
| Answer» C. \[3.5\times {{10}^{4}}yrs\] | |
| 1110. |
What kind of radioactive decay does not lead to the formation of a daughter nucleus that is an isobar of the parent nucleus [JIPMER 1999] |
| A. | a-rays |
| B. | b-rays |
| C. | Positron |
| D. | Electron capture |
| Answer» B. b-rays | |
| 1111. |
Half-life period of a metal is 20 days. What fraction of metal does remain after 80 days [BHU 1996] |
| A. | 1 |
| B. | 1/16 |
| C. | 1/4 |
| D. | 1/8 |
| Answer» C. 1/4 | |
| 1112. |
What is the value of decay constant of a compound having half-life time \[{{T}_{1/2}}=2.95\] days [AFMC 1997] |
| A. | \[2.7\times {{10}^{-5}}{{s}^{-1}}\] |
| B. | \[2.7\times {{10}^{6}}{{s}^{-1}}\] |
| C. | \[2.7\times {{10}^{-6}}{{s}^{-1}}\] |
| D. | \[3\times {{10}^{5}}{{s}^{-1}}\] |
| Answer» D. \[3\times {{10}^{5}}{{s}^{-1}}\] | |
| 1113. |
In a radioactive decay, an emitted electron comes from [CBSE 1994; Pb. PET 1999] |
| A. | Nucleus of the atom |
| B. | Inner orbital of the atom |
| C. | Outermost orbit of the atom |
| D. | Orbit having principal quantum number one |
| Answer» B. Inner orbital of the atom | |
| 1114. |
The half-life of \[_{38}^{90}Sr\] is 20 years. If its sample having initial activity of 8000 dis/min is taken, what would be its activity after 80 years [MP PMT 2000] |
| A. | 500 dis/min |
| B. | 800 dis/min |
| C. | 1000 dis/min |
| D. | 1600 dis/min |
| Answer» B. 800 dis/min | |
| 1115. |
What will be half-life period of a nucleus if at the end of 4.2 days, \[N=0.798\,{{N}_{0}}\] [MP PET 2000] |
| A. | 15 days |
| B. | 10 days |
| C. | 12.83 days |
| D. | 20 days |
| Answer» D. 20 days | |
| 1116. |
If 2.0 g of a radioactive substance has half-life of 7 days. The half-life of 1 g sample is [MP PET 2000] |
| A. | 7 days |
| B. | 14 days |
| C. | 28 days |
| D. | 35 days |
| Answer» B. 14 days | |
| 1117. |
If 12 g of sample is taken, and 6 g of a sample decays in 1 hr. The amount of sample showing decay in next hour is [AMU (Engg.) 1999] |
| A. | 3 g |
| B. | 1 g |
| C. | 2 g |
| D. | 6 g |
| Answer» B. 1 g | |
| 1118. |
The half-life of a radio isotope is 20 hours. After 60 hours, how much amount will be left behind [MP PMT 1991] |
| A. | 1/8 |
| B. | 1/4 |
| C. | 1/3 |
| D. | ½ |
| Answer» B. 1/4 | |
| 1119. |
The atomic mass of an element is 12.00710 amu. If there are 6 neutrons in the nucleus of the atom of the element, the binding energy per nucleon of the nucleus will be [MP PMT 1999] |
| A. | 7.64 MeV |
| B. | 76.4 MeV |
| C. | 764 MeV |
| D. | 0.764 MeV (\[{{e}^{-}}\]=0.00055 amu, \[p\]=1.00814 amu, \[n\]=1.00893 amu) |
| Answer» B. 76.4 MeV | |
| 1120. |
During a negative \[\beta \]-decay [MNR 1990; IIT 1985] |
| A. | An atomic electron is ejected |
| B. | An electron which is already present within the nucleus is ejected |
| C. | A neutron in the nucleus decays emitting an electron |
| D. | A part of the binding energy of the nucleus is converted into an electron |
| Answer» D. A part of the binding energy of the nucleus is converted into an electron | |
| 1121. |
The decay constant of a radioactive sample is \['\lambda '\]. The half-life and mean life of the sample are respectively [MNR 1990; IIT 1989] |
| A. | \[\frac{1}{\lambda },\,\frac{\ln \,2}{\lambda }\] |
| B. | \[\frac{\ln \,2}{\lambda },\,\frac{1}{\lambda }\] |
| C. | \[\lambda \,\ln \,2,\,\frac{1}{\lambda }\] |
| D. | \[\frac{\lambda }{\ln \,2},\,\frac{1}{\lambda }\] |
| Answer» C. \[\lambda \,\ln \,2,\,\frac{1}{\lambda }\] | |
| 1122. |
A freshly prepared radioactive source of half-life 2 hours emits radiations of intensity which is 64 times the permissible safe level. The minimum time after which it would be possible to work safely with this source is [IIT 1988] |
| A. | 6 hours |
| B. | 12 hours |
| C. | 24 hours |
| D. | 128 hours |
| Answer» C. 24 hours | |
| 1123. |
Radioactivity of a radioactive element remains \[\frac{1}{10}\] of the original radioactivity after 2.303 seconds. The half-life period is [CPMT 1985] |
| A. | 2.303 |
| B. | 0.2303 |
| C. | 0.693 |
| D. | 0.0693 |
| Answer» D. 0.0693 | |
| 1124. |
A radioactive substance has \[{{t}_{1/2}}\]60 minutes. After 3 hrs, what percentage of radioactive substance will remain [BHU 1995] |
| A. | 50% |
| B. | 75% |
| C. | 25% |
| D. | 12.5% |
| Answer» E. | |
| 1125. |
\[10gm\] of a radioactive substance is reduced to \[1.25gm\] after 15 days. Its \[1kg\] mass will reduce (in how many days) to \[500gm\] in |
| A. | 500 days |
| B. | 125 days |
| C. | 25 days |
| D. | 5 days |
| Answer» E. | |
| 1126. |
\[{{C}^{14}}\] is radioactive. The activity and the disintegration product are |
| A. | \[\beta \]-active, \[_{7}{{N}^{14}}\] |
| B. | \[\alpha \]- active, \[_{7}B{{e}^{10}}\] |
| C. | Positron active, \[_{5}{{B}^{14}}\] |
| D. | \[\gamma \]- active, \[{{C}^{14}}\] |
| Answer» B. \[\alpha \]- active, \[_{7}B{{e}^{10}}\] | |
| 1127. |
The half-life of a radionuclide is 69.3 minutes. What is its average life (in minutes) |
| A. | 100 |
| B. | \[{{10}^{-2}}\] |
| C. | \[{{(69.3)}^{-1}}\] |
| D. | \[0.693\times 69.3\] |
| Answer» B. \[{{10}^{-2}}\] | |
| 1128. |
The half-life period of a radioactive substance is 8 years. After 16 years, the mass of the substance will reduce from starting \[16.0g\] to [MP PMT 1999] |
| A. | \[8.0\,g\] |
| B. | \[6.0\,g\] |
| C. | \[4.0\,g\] |
| D. | \[2.0\,g\] |
| Answer» D. \[2.0\,g\] | |
| 1129. |
In radioactive decay which one of the following moves the fastest [MP PET/PMT 1998] |
| A. | \[\alpha \]-particle |
| B. | \[\beta \]-particle |
| C. | \[\gamma \]-rays |
| D. | Positron |
| Answer» D. Positron | |
| 1130. |
In a catalytic conversion of \[{{N}_{2}}\] to \[N{{H}_{3}}\] by Haber's process, the rate of reaction was expressed as change in the concentration of ammonia per time is \[40\times {{10}^{-3}}\,mol\,litr{{e}^{-1}}{{s}^{-1}}\]. If there are no side reaction, the rate of the reaction as expressed in terms of hydrogen is (in mol \[litr{{e}^{-1}}{{s}^{-1}}\]) |
| A. | \[60\times {{10}^{-3}}\] |
| B. | \[20\times {{10}^{-3}}\] |
| C. | 1.200 |
| D. | \[10.3\times {{10}^{-3}}\] |
| Answer» B. \[20\times {{10}^{-3}}\] | |
| 1131. |
The concentration of a reactant decreases from 0.2 M to 0.1 M in 10 minutes. The rate of the reaction is |
| A. | 0.01 M |
| B. | \[{{10}^{-2}}\] |
| C. | 0.01 mol \[d{{m}^{-3}}\,{{\min }^{-1}}\] |
| D. | 1 mol \[d{{m}^{-3}}\,{{\min }^{-1}}\] |
| Answer» D. 1 mol \[d{{m}^{-3}}\,{{\min }^{-1}}\] | |
| 1132. |
When a reaction is progressing |
| A. | The rate of the reaction goes on increasing |
| B. | The concentration of the products goes on decreasing |
| C. | The concentration of the reactants goes on decreasing |
| D. | The reaction rate always remains constant |
| Answer» D. The reaction rate always remains constant | |
| 1133. |
The rate of chemical reaction at constant temperature is proportional to |
| A. | The amount of products formed |
| B. | The product of masses of the reactants |
| C. | The product of the molar concentration of the reactants |
| D. | The mean free path of the reaction |
| Answer» D. The mean free path of the reaction | |
| 1134. |
If doubling the concentration of a reactant `A' increases the rate 4 times and tripling the concentration of `A' increases the rate 9 times, the rate is proportional to [AIIMS 1991] |
| A. | Concentration of `A' |
| B. | Square of concentration of `A' |
| C. | Under root of the concentration of `A' |
| D. | Cube of concentration of `A' |
| Answer» C. Under root of the concentration of `A' | |
| 1135. |
A first order reaction complete its 10% in 20 minutes then time required to complete its 19% is [Kerala CET 2005] |
| A. | 30 minutes |
| B. | 40 minutes |
| C. | 50 minutes |
| D. | 38 minutes |
| E. | 45 minutes |
| Answer» C. 50 minutes | |
| 1136. |
For the reaction\[2{{N}_{2}}{{O}_{5(g)}}\to 4N{{O}_{2(g)}}+{{O}_{2(g)}}\], if concentration of \[N{{O}_{2}}\] in 100 seconds is increased by \[5.2\times {{10}^{-3}}m\]. Then rate of reaction will be [Kerala CET 2005] |
| A. | \[1.3\times {{10}^{-5}}m{{s}^{-1}}\] |
| B. | \[5\times {{10}^{-4}}m{{s}^{-1}}\] |
| C. | \[7.6\times {{10}^{-4}}m{{s}^{-1}}\] |
| D. | \[2\times {{10}^{-3}}m{{s}^{-1}}\] |
| E. | \[2.5\times {{10}^{-5}}m{{s}^{-1}}\] |
| Answer» B. \[5\times {{10}^{-4}}m{{s}^{-1}}\] | |
| 1137. |
Rate of reaction [Pb. CET 2004] |
| A. | Decreases with increase in temperature |
| B. | Increases with increase in temperature |
| C. | May increase or decrease with increase in temperature |
| D. | Does not depend on temperature |
| Answer» D. Does not depend on temperature | |
| 1138. |
The rate law for the reaction \[RCl+NaOH(aq)\to ROH+NaCl\] is given by Rate \[={{K}_{1}}[RCl]\]. The rate of the reaction will be [IIT 1988] |
| A. | Doubled on doubling the concentration of sodium hydroxide |
| B. | Halved on reducing the concentration of alkyl halide to one half |
| C. | Decreased on increasing the temperature of the reaction |
| D. | Unaffected by increasing the temperature of the reaction |
| Answer» C. Decreased on increasing the temperature of the reaction | |
| 1139. |
In which of the following cases, does the reaction go farthest to completion [UPSEAT 2001] |
| A. | \[K={{10}^{3}}\] |
| B. | \[K={{10}^{-2}}\] |
| C. | \[K=10\] |
| D. | \[K=1\] |
| Answer» B. \[K={{10}^{-2}}\] | |
| 1140. |
The velocity constant of a reaction at 290 K was found to be \[3.2\times {{10}^{-3}}\]. At 300 K it will be [MP PMT 2004] |
| A. | \[1.28\times {{10}^{-2}}\] |
| B. | \[6.4\times {{10}^{-3}}\] |
| C. | \[9.6\times {{10}^{-3}}\] |
| D. | \[3.2\times {{10}^{-4}}\] |
| Answer» C. \[9.6\times {{10}^{-3}}\] | |
| 1141. |
A reaction is catalysed by ?X ?. Here ?X ? [MP PMT 2003] |
| A. | Decreases the rate constant of reaction |
| B. | Does not affect the equilibrium constant of reaction |
| C. | Decreases the enthalpy of reaction |
| D. | Decreases the activation energy |
| Answer» E. | |
| 1142. |
Which reaction characteristics are changing by the addition of a catalyst to a reaction at constant temperature (i) Activation energy (ii) Equilibrium constant (iii) Reaction entropy (iv) Reaction enthalpy [DCE 2003] |
| A. | (i) Only |
| B. | (iii) only |
| C. | (i) and I(ii) only |
| D. | All of these |
| Answer» B. (iii) only | |
| 1143. |
Which of the following statements is false in relation to enzyme [MP PMT 2003] |
| A. | pH affects their functioning |
| B. | Temperature affects their functioning |
| C. | They always increase activation energy |
| D. | Their reactions are specific |
| Answer» D. Their reactions are specific | |
| 1144. |
The rate of a reaction [CPMT 1973] |
| A. | Increases with increase in temperature |
| B. | Decreases with increase in temperature |
| C. | Does not depend on temperature |
| D. | Does not depend on concentration |
| Answer» B. Decreases with increase in temperature | |
| 1145. |
The temperature coefficient of a reaction is |
| A. | Specific reaction rate at \[{{25}^{o}}C\] |
| B. | Rate of the reaction at \[{{100}^{o}}C\] |
| C. | Ratio of the rate constants at temperatures \[{{35}^{o}}C\] and \[{{25}^{o}}C\] |
| D. | Ratio of the rate constants at two temperatures differing by \[{{1}^{o}}C\] |
| Answer» D. Ratio of the rate constants at two temperatures differing by \[{{1}^{o}}C\] | |
| 1146. |
Velocity constant of a reaction at 290 K was found to be\[3.2\times {{10}^{-3}}\]. At 310 K it will be about [KCET 1989, 91] |
| A. | \[1.28\times {{10}^{-2}}\] |
| B. | \[9.6\times {{10}^{-3}}\] |
| C. | \[6.4\times {{10}^{-3}}\] |
| D. | \[3.2\times {{10}^{-4}}\] |
| Answer» B. \[9.6\times {{10}^{-3}}\] | |
| 1147. |
The rate of a reaction is doubled for every \[{{10}^{o}}\] rise in temperature. The increase in reaction rate as a result of temperature rise from \[{{10}^{o}}\] to \[{{100}^{o}}\] is [KCET 1993; Kerala PET 2002; MP PET 2003] |
| A. | 112 |
| B. | 512 |
| C. | 400 |
| D. | 614 |
| Answer» C. 400 | |
| 1148. |
The temperature coefficient for reaction in which food deteriorates is 2. Then food deteriorates ...... times as rapidly at \[{{25}^{o}}C\] as it does at \[{{5}^{o}}C\] |
| A. | Two |
| B. | Four |
| C. | Six |
| D. | Twenty |
| Answer» C. Six | |
| 1149. |
The velocity of the chemical reaction doubles every \[{{10}^{o}}C\] rise of temperature. If the temperature is raised by \[{{50}^{o}}C\], the velocity of the reaction increases to about |
| A. | 32 times |
| B. | 16 times |
| C. | 20 times |
| D. | 50 times |
| Answer» B. 16 times | |
| 1150. |
The rate of disappearance of \[S{{O}_{2}}\] in the reaction \[2S{{O}_{2}}+{{O}_{2}}\to 2S{{O}_{3}}\] is \[1.28\times {{10}^{-3}}g/sec\] then the rate of formation of \[S{{O}_{3}}\] is [JIPMER 2002] |
| A. | \[0.64\times {{10}^{-3}}g/sec\] |
| B. | \[0.80\times {{10}^{-3}}g/sec\] |
| C. | \[1.28\times {{10}^{-3}}g/sec\] |
| D. | \[1.60\times {{10}^{-3}}g/sec\] |
| Answer» D. \[1.60\times {{10}^{-3}}g/sec\] | |