| Complete the equation for the following fission process: [AIPMT 1998] |
| \[_{92}{{U}^{235}}+{{\,}_{0}}{{n}^{1}}\,\xrightarrow[{}]{{}}{{\,}_{38}}S{{r}^{90}}+.......\] |
|
done
clear
B)
46.8 g
done
clear
C)
9.375 g
done
clear
D)
93.75 g
done
clear
View Answer play_arrow
question_answer10)
A)
neutron
done
clear
B)
antineutrino
done
clear
C)
proton
done
clear
D)
neutrino
done
clear
View Answer play_arrow
question_answer11) Which of the following is positively charge? [AIPMT 2001]
A)
\[\alpha -\]particle
done
clear
B)
\[\beta -\]particle
done
clear
C)
\[\gamma -\]rays
done
clear
D)
X-rays
done
clear
View Answer play_arrow
question_answer12) \[{{m}_{p}}\] and \[{{m}_{n}}\] are masses of proton and neutron respectively. An element of mass M has Z protons and N neutrons then: [AIPMT 2001]
A)
\[M>Z{{m}_{p}}+N{{m}_{n}}\]
done
clear
B)
\[M=Z{{m}_{p}}+N{{m}_{n}}\]
done
clear
C)
\[M<Z{{m}_{p}}+N{{m}_{n}}\]
done
clear
D)
M may be greater than, less than or equal to \[Z{{m}_{p}}+N{{m}_{n}},\] depending on nature of element
done
clear
View Answer play_arrow
question_answer13) In nuclear fission process, energy is released because: [AIPMT 2001]
A)
mass of products is more than mass of nucleus
done
clear
B)
total binding energy of products formed due to nuclear fission is more than the parent fissionable material
done
clear
C)
total binding energy of products formed due to nuclear fission is less than parent fissionable material
done
clear
D)
mass of some particles is converted into energy
done
clear
View Answer play_arrow
question_answer14) Half-life period of a radioactive substance is 6h. After 24 h activity is \[0.01\,\mu C,\] what was the initial activity? [AIPMT 2001]
A)
\[0.04\,\mu C\]
done
clear
B)
\[0.08\,\mu C\]
done
clear
C)
\[0.24\,\mu C\]
done
clear
D)
\[0.16\,\mu C\]
done
clear
View Answer play_arrow
question_answer15) Half-life of a radioactive substance is 12.5 h and its mass is 256 g. After what time, the amount of remaining substance is 1g? [AIPMT 2001]
A)
75 h
done
clear
B)
100 h
done
clear
C)
125 h
done
clear
D)
150 h
done
clear
View Answer play_arrow
question_answer16) In compound \[X(n,\,\,\alpha )\to \,{{\,}_{3}}L{{I}^{7}},\] the element X is: [AIPMT 2001]
A)
\[_{2}H{{e}^{4}}\]
done
clear
B)
\[_{5}{{B}^{10}}\]
done
clear
C)
\[_{5}{{B}^{9}}\]
done
clear
D)
\[_{4}B{{e}^{11}}\]
done
clear
View Answer play_arrow
question_answer17) A sample of radioactive elements contains \[4\times {{10}^{10}}\] active nuclei. If half-life of element is 10 days, then the number of decayed nuclei after 30 days is: [AIPMT 2002]
A)
\[0.5\times {{10}^{10}}\]
done
clear
B)
\[2\times {{10}^{10}}\]
done
clear
C)
\[3.5\times {{10}^{10}}\]
done
clear
D)
\[1\times {{10}^{10}}\]
done
clear
View Answer play_arrow
question_answer18) Which of the following are suitable for the fusion process? [AIPMT 2002]
A)
Light nuclei
done
clear
B)
Heavy nuclei
done
clear
C)
Elements lying in the middle of periodic table
done
clear
D)
Elements lying in the middle of binding energy curve
done
clear
View Answer play_arrow
question_answer19) When a deuterium is bombarded on \[_{8}{{O}^{16}}\] nucleus, an \[\alpha -\]particle is emitted then the product nucleus is: [AIPMT 2002]
A)
\[_{7}{{N}^{13}}\]
done
clear
B)
\[_{5}{{B}^{10}}\]
done
clear
C)
\[_{4}B{{e}^{9}}\]
done
clear
D)
\[_{7}{{N}^{14}}\]
done
clear
View Answer play_arrow
question_answer20) The volume occupied by an atom is greater than the volume of the nucleus by factor of about: [AIPMT 2003]
A)
\[{{10}^{10}}\]
done
clear
B)
\[{{10}^{15}}\]
done
clear
C)
\[{{10}^{1}}\]
done
clear
D)
\[{{10}^{5}}\]
done
clear
View Answer play_arrow
question_answer21) The mass of proton is \[1.0073\text{ }u\] and that of neutron is \[1.0087\text{ }u\] (\[u=\]atomic mass unit) The binding energy of \[_{2}H{{e}^{4}}\] is: [AIPMT 2003]
A)
\[28.4\text{ }MeV\]
done
clear
B)
\[0.061\text{ }u\]
done
clear
C)
\[0.0305\text{ }J\]
done
clear
D)
\[0.0305\text{ }erg\]
done
clear
View Answer play_arrow
question_answer22) A nuclear reaction given by: [AIPMT 2003] \[_{Z}{{X}^{A}}{{\to }_{Z+1}}{{Y}^{A}}{{+}_{-1}}{{e}^{0}}+\overline{v}\] represents:
A)
fusion
done
clear
B)
fission
done
clear
C)
\[\beta -\]decay
done
clear
D)
\[\gamma -\]decay
done
clear
View Answer play_arrow
question_answer23) A sample of radioactive element has a mass of \[10\text{ }g\] at an instant \[t=0\]. The approximate mass of this element in the sample after two mean lives is: [AIPMT 2003]
A)
3.70 g
done
clear
B)
6.30 g
done
clear
C)
1.35 g
done
clear
D)
2.50 g
done
clear
View Answer play_arrow
question_answer24) Solar energy is mainly caused due to: [AIPMT 2003]
A)
fusion of protons during synthesis of heavier elements
done
clear
B)
gravitational contraction
done
clear
C)
burning of hydrogen in the oxygen
done
clear
D)
fission of uranium present in the sun
done
clear
View Answer play_arrow
question_answer25) If in a nuclear fusion process, the masses of the fusing nuclei be m1and m2 and the mass of the resultant nucleus be \[{{m}_{3}},\] then [AIPMT (S) 2004]
A)
\[{{m}_{3}}={{m}_{1}}+{{m}_{2}}\]
done
clear
B)
\[{{m}_{3}}=|{{m}_{1}}-{{m}_{2}}|\]
done
clear
C)
\[{{m}_{3}}<({{m}_{1}}+{{m}_{2}})\]
done
clear
D)
\[{{m}_{3}}>({{m}_{1}}+{{m}_{2}})\]
done
clear
View Answer play_arrow
question_answer26) The half-life of radium is about 1600 years. Of 100 g of radium existing now, 25 g will remain unchanged after: [AIPMT (S) 2004]
A)
4800 year
done
clear
B)
6400 year
done
clear
C)
2400 year
done
clear
D)
3200 year
done
clear
View Answer play_arrow
question_answer27) \[{{M}_{p}}\] denotes the mass of a proton and \[{{M}_{n}}\] that of a neutron. A given nucleus, of binding energy B, contains Z protons and N neutrons. [AIPMT (S) 2004] The mass \[M(N,\text{ }Z)\] of the nucleus is given by :
A)
\[M\left( N,\text{ }Z \right)=N{{M}_{n}}+Z{{M}_{p}}-B{{e}^{2}}\]
done
clear
B)
\[M\left( N,Z \right)=N{{M}_{n}}+Z{{M}_{p}}+B/{{c}^{2}}\]
done
clear
C)
\[M\left( N,\text{ }Z \right)=N{{M}_{n}}+Z{{M}_{p}}-B/{{c}^{2}}\]
done
clear
D)
\[M\left( N,\text{ }Z \right)=N{{M}_{n}}+Z{{M}_{p}}+B/{{c}^{2}}\]
done
clear
View Answer play_arrow
question_answer28) In the reaction \[_{1}^{2}H+\,_{1}^{3}H\,\to \,_{2}^{4}He+\,_{0}^{1}n,\] if the binding energies of \[_{1}^{2}H\,,\,_{2}^{3}H\] and \[_{2}^{4}He\] are respectively a, b and c (in MeV), then the energy (in MeV) released in-this reaction is: [AIPMT (S) 2005]
A)
\[c+a-b\]
done
clear
B)
\[c-a-b\]
done
clear
C)
\[a+b+c\]
done
clear
D)
\[a+b-c\]
done
clear
View Answer play_arrow
question_answer29) Fission of nuclei is possible because the binding energy per nucleon in them: [AIPMT (S) 2005]
A)
increases with mass number at high mass numbers
done
clear
B)
decreases with mass number at high mass numbers
done
clear
C)
increases with mass number at low mass numbers
done
clear
D)
decreases with mass number at low mass numbers
done
clear
View Answer play_arrow
question_answer30) In any fission process the ratio \[\frac{\text{mass}\,\text{of}\,\text{fission}\,\text{products}}{\text{mass}\,\text{of}\,\text{parent}\,\text{nucleus}}\,\] is: [AIPMT (S) 2005]
A)
less than 1
done
clear
B)
greater than 1
done
clear
C)
equal to 1
done
clear
D)
depends on the mass of parent nucleus
done
clear
View Answer play_arrow
question_answer31) The binding energy of deuteron is 2.2 MeV and that of \[_{2}^{4}He\] is 28 MeV. If two deuterons are fused to form one \[_{2}^{4}He\] then the energy released is: [AIPMT (S) 2006]
A)
25.8 MeV
done
clear
B)
23.6 MeV
done
clear
C)
19.2 MeV
done
clear
D)
30.2 MeV
done
clear
View Answer play_arrow
question_answer32) In a radioactive material die activity at time \[{{t}_{1}}\] is \[{{R}_{1}}\] and at a later time \[{{t}_{2}},\] it is \[{{R}_{2}}\]. If the dacay constant of the material is \[\lambda ,\] then : [AIPMT (S) 2006]
A)
\[{{R}_{1}}={{R}_{2}}\,{{e}^{-\lambda ({{t}_{1}}-{{t}_{2}})}}\]
done
clear
B)
\[{{R}_{1}}={{R}_{2}}\,{{e}^{\lambda ({{t}_{1}}-{{t}_{2}})}}\]
done
clear
C)
\[{{R}_{1}}={{R}_{2}}\,({{t}_{2}}/{{t}_{1}})\]
done
clear
D)
\[{{R}_{1}}={{R}_{2}}\]7
done
clear
View Answer play_arrow
question_answer33) The radius of germanium (Ge) nuclide is measured to be twice the radius of \[_{4}^{9}Be\]. The number of nucleons in Ge are: [AIPMT (S) 2006]
A)
73
done
clear
B)
74
done
clear
C)
75
done
clear
D)
72
done
clear
View Answer play_arrow
question_answer34) In radioactive decay process, the negatively charged emitted \[\beta -\]particles are: [AIPMT (S) 2007]
A)
the electrons present inside the nucleus
done
clear
B)
the electrons produced as a result of the decay of neutrons inside the nucleus
done
clear
C)
the electrons produced as a result of collisions between atoms
done
clear
D)
the electrons orbiting around the nucleus
done
clear
View Answer play_arrow
question_answer35) A nucleus \[_{Z}^{A}X\] has mass represented by \[M(A,\text{ }Z).\] If \[{{M}_{p}}\] and \[{{M}_{n}}\] denote the mass of proton and neutron respectively and BE the binding energy (in MeV), then: [AIPMT (S) 2007]
A)
\[BE=[M(A,\,Z)-Z{{M}_{p}}-(A-Z){{M}_{n}}]\text{ }{{c}^{2}}\]
done
clear
B)
\[BE=[Z{{M}_{p}}+(A-Z)\,{{M}_{n}}-M(A,\,Z)]{{c}^{2}}\]
done
clear
C)
\[BE=[Z{{M}_{p}}+A{{M}_{n}}-M(A,\,\,Z)]{{c}^{2}}\]
done
clear
D)
\[BE=M(A,\,Z)-Z{{M}_{p}}-(A-Z)\,{{M}_{n}}\]
done
clear
View Answer play_arrow
question_answer36) If the nucleus \[_{13}^{27}Al\] has a nuclear radius of about 3.6 fm, then \[_{52}^{125}Te\] would have its radius approximately as: [AIPMT (S) 2007]
A)
6.0 fm
done
clear
B)
9.6 fm
done
clear
C)
12.0 fm
done
clear
D)
4.8 fm
done
clear
View Answer play_arrow
question_answer37) Two radioactive substances A and B have decay constants \[5\,\lambda ,\] and \[\lambda \] respectively. At \[t=0\] they have the same number of nuclei. The ratio of number of nuclei of A to those of B will be \[{{\left( \frac{1}{e} \right)}^{2}}\] after a time interval: [AIPMT (S) 2007]
A)
\[\frac{1}{4\lambda }\]
done
clear
B)
\[4\,\lambda \]
done
clear
C)
\[2\,\lambda \]
done
clear
D)
\[\frac{1}{2\lambda }\]
done
clear
View Answer play_arrow
question_answer38) Two radioactive materials \[{{X}_{1}}\] and \[{{X}_{2}}\] have decay constants \[5\lambda \] and \[\lambda \] respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of \[{{X}_{1}}\] to that of \[{{X}_{2}}\] will be \[\frac{1}{e}\] after a time [AIPMPT (S) 2008]
A)
\[\lambda \]
done
clear
B)
\[\frac{1}{2}\lambda \]
done
clear
C)
\[\frac{1}{4\lambda }\]
done
clear
D)
\[\frac{e}{\lambda }\]
done
clear
View Answer play_arrow
question_answer39) If \[M(A,\text{ }Z),\] \[{{M}_{p}}\] and M, denote the masses of the nucleus \[_{Z}^{A}X,\]proton and neutron respectively in units of \[u(1u=931.5MeV/{{c}^{2}})\] and BE represents its binding energy in M [AIPMPT (S) 2008]
A)
\[M(A,Z)=Z{{M}_{p}}+(A-Z){{M}_{n}}-BE/{{c}^{2}}\]
done
clear
B)
\[M(A,Z)=Z{{M}_{p}}+(A-Z){{M}_{n}}+BE\]
done
clear
C)
\[M(A,Z)=Z{{M}_{p}}+(A-Z){{M}_{n}}-BE\]
done
clear
D)
\[M(A,Z)=Z{{M}_{p}}+(A-Z){{M}_{n}}-BE/{{c}^{2}}\]
done
clear
View Answer play_arrow
question_answer40) Two nuclei have their mass numbers in the ratio of 1 : 3. The ratio of their, nuclear densities would be [AIPMPT (S) 2008]
A)
1 : 3
done
clear
B)
3 : 1
done
clear
C)
\[{{(3)}^{1/3}}:1\]
done
clear
D)
1 : 1
done
clear
View Answer play_arrow
question_answer41) In the nuclear decay given below\[_{Z}^{A}Z\xrightarrow{{}}\,_{Z+1}^{4}Y\xrightarrow{{}}\,_{Z-1}^{A-4}B*\xrightarrow{{}}\,_{Z-1}^{A-4}B,\]the particles emitted in the sequence are [AIPMT (S) 2009]
A)
\[\beta ,\,\,\alpha ,\,\,\gamma \]
done
clear
B)
\[\gamma ,\,\,\beta ,\,\,\alpha \]
done
clear
C)
\[\beta ,\,\,\gamma ,\,\,\alpha \]
done
clear
D)
\[\alpha ,\,\,\beta ,\,\,\gamma \]
done
clear
View Answer play_arrow
question_answer42) The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter is an [AIPMT (S) 2009]
A)
isobar of parent
done
clear
B)
isomer of parent
done
clear
C)
isotone of parent
done
clear
D)
isotope of parent
done
clear
View Answer play_arrow
question_answer43) The mass of a \[_{\text{3}}^{\text{7}}Li\] nucleus is 0.042 u less than the sum of the masses of all its nucleons. The binding energy per nucleon of \[_{\text{3}}^{\text{7}}Li\] nucleus is nearly [AIPMT (S) 2010]
A)
46 MeV
done
clear
B)
5.6 MeV
done
clear
C)
3.9 MeV
done
clear
D)
23 MeV
done
clear
View Answer play_arrow
question_answer44) The activity of a radioactive sample is measured as \[{{N}_{0}}\] counts per minute at \[t=0\] and \[{{N}_{0}}/e\] counts per minute at \[t=5\] min. The time (in minute) at which the activity reduces to half its value is [AIPMT (S) 2010]
A)
\[\text{lo}{{\text{g}}_{\text{e}}}\text{2/5}\]
done
clear
B)
\[\frac{5}{{{\log }_{e}}2}\]
done
clear
C)
\[5{{\log }_{10}}2\]
done
clear
D)
\[5{{\log }_{e}}2\]
done
clear
View Answer play_arrow
question_answer45) The decay constant of a radio isotope is \[\lambda \]. If \[{{A}_{1}}\] and \[{{A}_{2}}\] are its activities at times \[{{t}_{1}}\] and \[{{t}_{2}}\] respectively, the number of nuclei which have decayed during the time \[({{t}_{1}}-{{t}_{2}})\] [AIPMT (M) 2010]
A)
\[{{A}_{1}}{{t}_{1}}-{{A}_{2}}{{t}_{2}}\]
done
clear
B)
\[{{A}_{1}}-{{A}_{2}}\]
done
clear
C)
\[\frac{({{A}_{1}}-{{A}_{2}})}{\lambda }\]
done
clear
D)
\[\lambda ({{A}_{1}}-{{A}_{2}})\]
done
clear
View Answer play_arrow
question_answer46) The binding energy per nucleon in deuterium and helium nuclei are 1.1 MeV and 7.0 MeV, respectively. When two deuterium nuclei fuse to form a helium nucleus the energy released in the fusion is [AIPMT (M) 2010]
A)
23.6 MeV
done
clear
B)
2.2 MeV
done
clear
C)
28.0 MeV
done
clear
D)
30.2 MeV
done
clear
View Answer play_arrow
question_answer47) Two radioactive nuclei P and Q, in a given sample decay into a stable nucleous R. At time \[t=0,\] number of P species are \[4\,{{N}_{0}}\] and that of Q are \[{{N}_{0}}\] Half-life of P (for conversion to K) is 1 min where as that of Q is 2 min. Initially there are no nuclei of R present in the sample. When number of nuclei of P and Q are equal, the number of nuclei of R present in the sample would be [AIPMT (M) 2011]
A)
\[3{{N}_{0}}\]
done
clear
B)
\[\frac{9{{N}_{0}}}{2}\]
done
clear
C)
\[\frac{5{{N}_{0}}}{2}\]
done
clear
D)
\[2{{N}_{0}}\]
done
clear
View Answer play_arrow
question_answer48) A radioactive nucleus of mass M emits a photon of frequency v and the nucleus recoils. The recoil energy will be [AIPMT (S) 2011]
A)
x\[{{h}^{2}}{{v}^{2}}/2M{{c}^{2}}\]
done
clear
B)
zero
done
clear
C)
\[hv\]
done
clear
D)
\[M{{c}^{2}}-hv\]
done
clear
View Answer play_arrow
question_answer49) The power obtained in a reactor using \[{{U}^{235}}\] disintegration is 1000 kW. The mass decay of \[{{U}^{235}}\] per hour is [AIPMT (S) 2011]
A)
\[20\mu g\]
done
clear
B)
\[40\mu g\]
done
clear
C)
\[1\,\mu g\]
done
clear
D)
\[10\,\mu g\]
done
clear
View Answer play_arrow
question_answer50) The half-life of a radioactive isotope X is 50 yr. It decays to another element Y which is stable. The two elements X and Y were found to be in the ratio of 1 : 15 in a sample of a given rock. The age of the rock was estimated to be [AIPMT (S) 2011]
A)
200 yr
done
clear
B)
250 yr
done
clear
C)
100 yr
done
clear
D)
150 yr
done
clear
View Answer play_arrow
question_answer51) Fusion reaction takes place at high temperature because [AIPMT (S) 2011]
A)
atoms get ionised at high temperature
done
clear
B)
kinetic energy is high enough to overcome the coulomb repulsion between nuclei
done
clear
C)
molecules break up at high temperature
done
clear
D)
nuclei break up at high temperature
done
clear
View Answer play_arrow
question_answer52) A nucleus \[_{n}^{m}X\] emits one a-particle and two \[\beta -\]particles. The resulting nucleus is [AIPMT (S) 2011]
A)
\[_{n}^{m-6}Z\]
done
clear
B)
\[_{n}^{m-4}X\]
done
clear
C)
\[_{n-2}^{m-4}Y\]
done
clear
D)
\[_{n-4}^{m-6}Z\]
done
clear
View Answer play_arrow
question_answer53) The half-life of a radioactive nucleus is 50 days. The time interval \[({{t}_{2}}-{{t}_{1}})\] between the time t2 when \[\frac{2}{3}\] of it has decayed and the time \[{{t}_{1}}\] when \[\frac{1}{3}\] of it had decayed is [AIPMT (M) 2012]
A)
30 days
done
clear
B)
50 days
done
clear
C)
60 days
done
clear
D)
15 days
done
clear
View Answer play_arrow
question_answer54) If the nuclear radius of \[^{27}Al\] is 3.6 Fermi, the approximate nuclear radius of \[^{64}Cu\] in Fermi is [AIPMT (S) 2012]
A)
2.4
done
clear
B)
1.2
done
clear
C)
4.8
done
clear
D)
3.6
done
clear
View Answer play_arrow
question_answer55) A mixture consists of two radioactive materials \[{{A}_{1}}\] and \[{{A}_{2}}\] with half-lives of 20s and 10s respectively. Initially the mixture has 40 g of \[{{A}_{1}}\] and 160 g of \[{{A}_{2}}\]. The amount of the two in the mixture will become equal after [AIPMT (S) 2012]
A)
60 s
done
clear
B)
80 s
done
clear
C)
20 s
done
clear
D)
40 s
done
clear
View Answer play_arrow
question_answer56) The half-life of a radioactive isotope X is 20 yr. It decays to another element Y which is stable. The two elements X and Y were found to be in the ratio 1 : 7 in a sample of a given rock. The age of the rock is estimated to be [NEET 2013]
A)
40 yr
done
clear
B)
60 yr
done
clear
C)
80 yr
done
clear
D)
100 yr
done
clear
View Answer play_arrow
question_answer57) A certain mass of hydrogen is changed to helium by the process of fusion. The mass defect in fusion reaction is 0.02866 u. The energy liberated per u is (given \[1\text{ }u=931\text{ }MeV\]) [NEET 2013]
A)
2.67 MeV
done
clear
B)
26.7 MeV
done
clear
C)
6.675 MeV
done
clear
D)
13.35 MeV
done
clear
View Answer play_arrow
question_answer58) The binding energy per nucleon of \[_{3}^{7}Li\] and \[_{2}^{4}He\] nuclei are 5.60 MeV and 7.06 MeV, respectively. In the nuclear reaction\[_{3}^{7}Li+_{1}^{1}H\to _{2}^{4}He\]\[+_{2}^{4}He+Q,\] the value of energy Q released is [NEET 2014]
A)
19.6 MeV
done
clear
B)
- 2.4 MeV
done
clear
C)
8.4 MeV
done
clear
D)
17.3 MeV
done
clear
View Answer play_arrow
question_answer59) A radio isotope X with a half-life \[1.4\times {{10}^{9}}\,\,yr\] decays of Y which is stable. A sample of the rock from a cave was found to contain X and Y in the ratio 1 : 7. The age of the rock is [NEET 2014]
A)
\[1.96\times {{10}^{9}}\,yr\]
done
clear
B)
\[3.92\times {{10}^{9}}\,yr\]
done
clear
C)
\[4.20\times {{10}^{9}}yr\]
done
clear
D)
\[8.40\times {{10}^{9}}\,yr\]
done
clear
View Answer play_arrow
question_answer60) If radius of the \[_{13}^{27}Al\] nucleus is taken to be \[{{R}_{Al}},\] then the radius of \[_{53}^{125}Te\] nucleus is nearly [NEET 2015]
A)
\[{{\left( \frac{53}{13} \right)}^{\frac{1}{3}}}{{R}_{Al}}\]
done
clear
B)
\[\frac{5}{3}{{R}_{Al}}\]
done
clear
C)
\[\frac{3}{5}{{R}_{Al}}\]
done
clear
D)
\[{{\left( \frac{13}{53} \right)}^{\frac{1}{3}}}{{R}_{Al}}\]
done
clear
View Answer play_arrow
question_answer61) Radioactive material \['A'\] has decay constant \['8\lambda '\] and material \['B'\] has decay constant \['\lambda '\]. Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material \['B'\] to that \['A'\] will be \[\frac{1}{e}\]? [NEET-2017]
A)
\[\frac{1}{9\lambda }\]
done
clear
B)
\[\frac{1}{\lambda }\]
done
clear
C)
\[\frac{1}{7\lambda }\]
done
clear
D)
\[\frac{1}{8\lambda }\]
done
clear
View Answer play_arrow
question_answer62) For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is [NEET - 2018]
A)
30
done
clear
B)
10
done
clear
C)
20
done
clear
D)
15
done
clear
View Answer play_arrow
question_answer63) When a uranium isotope \[_{\,\,\,92}^{235}\bigcup \]is bombarded with a neutron, it generates \[_{36}^{89}Kr\]neutrons and: [NEET 2020]
A)
\[_{40}^{91}Zr\]
done
clear
B)
\[_{\,\,36}^{101}Kr\]
done
clear
C)
\[_{\,\,36}^{103}Kr\]
done
clear
D)
\[_{\,\,56}^{144}Ba\]
done
clear
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question_answer64) The energy equivalent of 0.5 g of a substance is: [NEET 2020]
A)
\[4.5\times {{10}^{13}}J\]
done
clear
B)
\[1.5\times {{10}^{13}}J\]
done
clear
C)
\[0.5\times {{10}^{13}}J\]
done
clear
D)
\[4.5\times {{10}^{16}}J\]
done
clear
View Answer play_arrow
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