MCQOPTIONS
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MCQOPTIONS
This section includes 39 Mcqs, each offering curated multiple-choice questions to sharpen your Chemistry knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
If \[_{92}{{U}^{235}}\] nucleus absorbs a neutron and disintegrates in \[_{54}X{{e}^{139}}\], \[_{38}S{{r}^{94}}\] and X, then what will be the product X [CBSE 2002] |
| A. | a-particle |
| B. | b-particle |
| C. | 2-neutrons |
| D. | 3-neutrons |
| Answer» E. | |
| 2. |
A radioactive nucleide X decays at the rate of \[1.00\times {{10}^{5}}\] disintegration \[{{s}^{-1}}{{g}^{-1}}\]. Radium decays at the rate of \[3.70\times {{10}^{10}}\] disintegration \[{{s}^{-1}}{{g}^{-1}}\]. The activity of X in millicuries \[{{g}^{-1}}\] \[(m\,ci\,{{g}^{-1}})\] is [MP PET 2001] |
| A. | 0.027 |
| B. | \[0.270\times {{10}^{-5}}\] |
| C. | 0.0027 |
| D. | 0.00027 |
| Answer» C. 0.0027 | |
| 3. |
If 1 microgram of radium has disintegrated for 500 years, how many alpha particles will be emitted per second |
| A. | \[2.92\times {{10}^{4}}/\sec \] |
| B. | \[292\times {{10}^{4}}/\sec \] |
| C. | \[0.292\times {{10}^{4}}/\sec \] |
| D. | \[29.2\times {{10}^{4}}/\sec \] |
| Answer» B. \[292\times {{10}^{4}}/\sec \] | |
| 4. |
The missing particle in the reaction, \[_{92}^{235}U+_{0}^{1}n\,\to {{\,}_{56}}B{{a}^{146}}+...+3_{0}^{1}n\] is [DPMT 2001] |
| A. | \[_{32}^{87}Ge\] |
| B. | \[_{35}^{89}Br\] |
| C. | \[_{36}^{87}Kr\] |
| D. | \[_{35}^{86}Br\] |
| Answer» D. \[_{35}^{86}Br\] | |
| 5. |
Sulphur-35 (34.96903 amu) emits a \[\beta -\]particle but no \[\gamma -\]rays, the product is chlorine-35 (34.96885 amu). The maximum energy emitted by the \[\beta -\]particle is [DPMT 2004] |
| A. | 0.016767 MeV |
| B. | 1.6758 MeV |
| C. | 0.16758 MeV |
| D. | 16.758 MeV |
| Answer» B. 1.6758 MeV | |
| 6. |
Oxygen contains 90% of \[{{O}^{16}}\] and 10% of \[{{O}^{18}}\]. Its atomic mass is [KCET 1998] |
| A. | 17.4 |
| B. | 16.2 |
| C. | 16.5 |
| D. | 17 |
| Answer» C. 16.5 | |
| 7. |
\[_{92}{{U}^{235}}+n\to \]fission product+neutron\[+3.20\times {{10}^{-11}}J\]. The energyreleased when \[1g\] of \[_{92}{{U}^{235}}\] undergoes fission is [CBSE PMT 1997] |
| A. | \[12.75\times {{10}^{8}}kJ\] |
| B. | \[18.60\times {{10}^{9}}kJ\] |
| C. | \[8.21\times {{10}^{7}}kJ\] |
| D. | \[6.55\times {{10}^{6}}kJ\] |
| Answer» D. \[6.55\times {{10}^{6}}kJ\] | |
| 8. |
A wood specimen from an archeological centre shows a \[_{6}^{14}C\] activity of 5.0 counts/min/gm of carbon. What is the age of the specimen \[({{t}_{1/2}}\]for \[_{6}^{14}C\] is 5000 years) and a freshly cut wood gives 15 counts/min/gm of carbon [AMU (Engg.) 2002] |
| A. | \[5.78\times {{10}^{4}}\]years |
| B. | \[9.85\times {{10}^{4}}\]years |
| C. | \[7.85\times {{10}^{3}}\]years |
| D. | \[0.85\times {{10}^{4}}\]years |
| Answer» D. \[0.85\times {{10}^{4}}\]years | |
| 9. |
The half-life period of \[P{{b}^{210}}\] is 22 years. If 2 gm of \[P{{b}^{210}}\] is taken, then after 11 years how much of \[P{{b}^{210}}\] will be left [KCET 2001] |
| A. | 1.414 gm |
| B. | 2.428 gm |
| C. | 3.442 gm |
| D. | 4.456 gm |
| Answer» B. 2.428 gm | |
| 10. |
The half-life period of a radioactive substance is 140 days. After how much time 15 g will decay from 16 g sample of it [AFMC 2002] |
| A. | 140 days |
| B. | 560 days |
| C. | 280 days |
| D. | 420 days |
| Answer» C. 280 days | |
| 11. |
The half-life of 1 gm of radioactive sample is 9 hours. The radioactive decay obeys first order kinetics. The time required for the original sample to reduce to 0.2 gm is [AMU (Engg.) 2002] |
| A. | 15.6 hours |
| B. | 156 hours |
| C. | 20.9 hours |
| D. | 2.09 hours |
| Answer» D. 2.09 hours | |
| 12. |
A radioactive element with half-life 6.5 hrs has \[48\times {{10}^{19}}\]atoms. Number of atoms left after 26 hrs [BHU 2003] |
| A. | \[24\times {{10}^{19}}\] |
| B. | \[12\times {{10}^{19}}\] |
| C. | \[3\times {{10}^{19}}\] |
| D. | \[6\times {{10}^{19}}\] |
| Answer» D. \[6\times {{10}^{19}}\] | |
| 13. |
What is the half-life of a radioactive substance if 87.5% of any given amount of the substance disintegrates in 40 minutes [Kerala CET 1996] |
| A. | 160 min |
| B. | 10 min |
| C. | 20 min |
| D. | 13 min 20 sec |
| Answer» E. | |
| 14. |
Number of a--particles emitted per second by a radioactive element falls to 1/32 of its original value in 50 days. The half-life-period of this elements is [AMU 2001] |
| A. | 5 days |
| B. | 15 days |
| C. | 10 days |
| D. | 20 days |
| Answer» D. 20 days | |
| 15. |
A first order nuclear reaction is half completed in 45 minutes. How long does it need 99.9% of the reaction to be completed [KCET 2001] |
| A. | 5 hours |
| B. | 7.5 hours |
| C. | 10 hours |
| D. | 20 hours |
| Answer» C. 10 hours | |
| 16. |
The radium and uranium atoms in a sample of uranium mineral are in the ratio of \[1:2.8\times {{10}^{6}}\]. If half-life period of radium is 1620 years, the half-life period of uranium will be [MP PMT 1999] |
| A. | \[45.3\times {{10}^{9}}\] years |
| B. | \[45.3\times {{10}^{10}}\] years |
| C. | \[4.53\times {{10}^{9}}\] years |
| D. | \[4.53\times {{10}^{10}}\] years |
| Answer» D. \[4.53\times {{10}^{10}}\] years | |
| 17. |
The activity of carbon-14 in a piece of an ancient wood is only 12.5%. If the half-life period of carbon-14 is 5760 years, the age of the piece of wood will be \[(\log \,2=0.3010)\] [MP PMT 1999] |
| A. | \[17.281\times {{10}^{2}}\] years |
| B. | \[172.81\times {{10}^{2}}\] years |
| C. | \[1.7281\times {{10}^{2}}\] years |
| D. | \[1728.1\times {{10}^{2}}\] years |
| Answer» C. \[1.7281\times {{10}^{2}}\] years | |
| 18. |
The half-life of a radioactive isotope is 3 hours. Value of its disintegration constant is [BHU 2002] |
| A. | 0.231 per hr |
| B. | 2.31 per hr |
| C. | 0.2079 per hr |
| D. | 2.079 per hr |
| Answer» B. 2.31 per hr | |
| 19. |
The number value \[6.022\text{ }\times \text{1}{{\text{0}}^{23}}\] is also called |
| A. | Dalton Number |
| B. | Avagadro's number |
| C. | Atomic Number |
| D. | Mass Number |
| Answer» C. Atomic Number | |
| 20. |
Which of the following are the constituents of matter? A. Atoms B. Molecules C. Solid |
| A. | A and B only |
| B. | A and C only |
| C. | B and C only |
| D. | A, B and C |
| Answer» B. A and C only | |
| 21. |
Valency of Cr in \[CrP{{O}_{4}}\] is |
| A. | 4 |
| B. | 3 |
| C. | 2 |
| D. | 1 |
| Answer» C. 2 | |
| 22. |
Age of fossil may be found out by determining the ratio of two isotopes of carbon. The isotopes are [CDS] |
| A. | C-12 and C-13 |
| B. | C-13 and C-14 |
| C. | C-12 and C-14 |
| D. | C-12 and carbon black |
| Answer» D. C-12 and carbon black | |
| 23. |
Heavy water implies [CDS] |
| A. | water which is used in heavy industries such as thermal power plants |
| B. | water which contains \[S{{O}_{4}}^{2-}\] and \[C{{I}^{-}}\] of calcium and magnesium |
| C. | deuterated water |
| D. | water which has maximum density |
| Answer» D. water which has maximum density | |
| 24. |
Which one of the following is not needed in a nuclear fission reactor? [CDS] |
| A. | Moderator |
| B. | Coolant |
| C. | Accelerator |
| D. | Control device |
| Answer» D. Control device | |
| 25. |
Which one of the following is heavy water used in nuclear reactor? [CDS] |
| A. | Water having molecular weight 18 u |
| B. | Water having molecular weight 20 u |
| C. | Water at \[4{}^\circ C\] but having molecular weight 19u |
| D. | Water below the ice in a frozen sea |
| Answer» C. Water at \[4{}^\circ C\] but having molecular weight 19u | |
| 26. |
An \[\alpha \]-particle consists of which of the following?[CDS] |
| A. | 2 protons and 2 neutrons |
| B. | 1 proton and 1 electron |
| C. | 2 protons and 4 neutrons |
| D. | 1 proton and 1 neutron |
| Answer» B. 1 proton and 1 electron | |
| 27. |
Which of the following isotopes of carbon is/are used in carbon dating? [CDS] |
| A. | \[_{6}{{C}^{12}}\] only |
| B. | \[_{6}{{C}^{13}}\] only |
| C. | \[_{6}{{C}^{14}}\] only |
| D. | \[_{6}{{C}^{12}}\] and \[_{6}{{C}^{14}}\] |
| Answer» D. \[_{6}{{C}^{12}}\] and \[_{6}{{C}^{14}}\] | |
| 28. |
Match List I with List II and select the correct answer using the code given below the Lists : [NDA] List I (Scientist) List II (Discovery)A. Goldstein1.Atomic theoryB. Chadwick2.ProtonC. J.J Thomson3.NeutronD. John Dalton4.Electron |
| A. | A-2,B-3,C-4,D-1 |
| B. | A-2,B-4,C-3,D-1 |
| C. | A-1,B-4,C-3,D-2 |
| D. | A-1,B-3,C-4,D-2 |
| Answer» B. A-2,B-4,C-3,D-1 | |
| 29. |
Which one among the following transitions of electron of hydrogen atom emits radiation of the shortest wavelength? [NDA] |
| A. | n = 2 to n = 1 |
| B. | n = 3 to n = 2 |
| C. | n = 4 to n = 3 |
| D. | n = 5 to n = 4 |
| Answer» B. n = 3 to n = 2 | |
| 30. |
Which of the following pairs is/are correctly matched? [NDA] 1. Isotopes: Atoms with same atomic number but different atomic mass 2. Isobars: Atoms with same number of neutrons but different atomic number 3. Isotones: Atoms with same mass number but different atomic number. Select the correct answer using the code given below:Code: |
| A. | 1, 2 and 3 |
| B. | 1 only |
| C. | 1 and 2 only |
| D. | 2 only |
| Answer» C. 1 and 2 only | |
| 31. |
Which one among the following is correct regarding \[{}^{20}Ne,{}^{23}N{{a}^{+}},{}^{19}{{F}^{-}}and\,\,{}^{24}M{{g}^{2+}}\]? [NDA] |
| A. | They are isomers of each other |
| B. | They are isotopes of each other |
| C. | They are isoelectronic with each other |
| D. | All of the above |
| Answer» D. All of the above | |
| 32. |
The number of protons in a negatively charged atom (anion) is[NDA] |
| A. | more than the atomic number of the element |
| B. | less than the atomic number of the element |
| C. | more than the number of electrons in the atom |
| D. | less than the number of electrons in the atom |
| Answer» E. | |
| 33. |
Which one among the following most correctly determines the atomic number of an element[NDA] |
| A. | Number of protons |
| B. | Number of protons and electrons |
| C. | Number of ions |
| D. | Number of nucleons |
| Answer» B. Number of protons and electrons | |
| 34. |
The number of neutrons in \[_{7}A{{I}^{27}}\] is [NDA] |
| A. | 40 |
| B. | 27 |
| C. | 14 |
| D. | 13 |
| Answer» D. 13 | |
| 35. |
What is the number of water molecules present in a tiny drop of water (volume 0.0018 ml) at room temperature? [NDA] |
| A. | \[4.84\times {{10}^{17}}\] |
| B. | \[4.184\times {{10}^{18}}\] |
| C. | \[6.023\times {{10}^{19}}\] |
| D. | \[6.023\times {{10}^{23}}\] |
| Answer» D. \[6.023\times {{10}^{23}}\] | |
| 36. |
The atomic weights are expressed in terms of atomic mass unit. Which one of the following is used as a standard? [NDA] |
| A. | \[^{1}{{H}_{1}}\] |
| B. | \[^{12}{{C}_{6}}\] |
| C. | \[^{16}{{O}_{8}}\] |
| D. | \[^{35}C{{I}_{17}}\] |
| Answer» C. \[^{16}{{O}_{8}}\] | |
| 37. |
Which one among the following is correct regarding \[{}^{20}Ne,{}^{23}N{{a}^{+}},{}^{19}{{F}^{-}}and\,\,{}^{24}M{{g}^{2+}}\]? [CDS] |
| A. | They are isomers of each other |
| B. | They are isotopes of each other |
| C. | They are isoelectronic with each other |
| D. | All of the above |
| Answer» D. All of the above | |
| 38. |
Which one among the following statements about an atom is not correct? [CDS] |
| A. | Atoms always combine to form molecules |
| B. | Atoms are the basic units from which molecules and ions are formed |
| C. | Atoms are always neutral in nature |
| D. | Atoms aggregate in large numbers to form the matter that we can see, feel and touch |
| Answer» E. | |
| 39. |
Which of the following statements is /are correct? According to Dalton's theoryA. An atom is the smallest particle of matterB. An atom is the smallest particle of an elementC. An atom is the smallest indivisible particle of an element that can take part in a chemical changeD. An atom is the radioactive emission |
| A. | A, B, and C |
| B. | B, C and D |
| C. | A, C and D |
| D. | A and D |
| Answer» B. B, C and D | |