873 + Interview Questions in NUCLEAR-PHYSICS IN GENERAL AWARENESS Page 4 InterviewSolution

151.	From the following equation pick out the possible nuclear fusion reactionsA. `._6C^(13) +._1H^1 rarr ._6C^(14) +4.3MeV`B. `._6C^(13) +._1H^1 rarr ._7C^(13) +2MeV`C. `._7C^(14) +._1H^1 rarr ._8O^(15) +7.3MeV`D. `._(92)U^(235)+._(0)n^1`
Answer» Correct Answer - a,b,c

Discussion

152.	Fusion reaction is initiated with the help ofA. low temperatureB. high temperatureC. neutronsD. any particle
Answer» Correct Answer - B

Discussion

153.	The `(B.E)/(A)` for deutron and an `alpha`-particle are `X_(1)` and `X_(2)` respectively. The energy released `alpha`-particle isA. `4(X_(2)-X_(1))`B. `2(X_(2)-X_(1))`C. `4(X_(2)+X_(1))`D. `(X_(2)-X_(1))/(4)`
Answer» Correct Answer - A

Discussion

154.	If `Q_(1)` and `Q_(2)` are the energies released in the fusion of hydrogen in Carbon-nitrogen cycle and proton-proton cycle respectively then cycle repespectively thenA. `Q_(1) gt Q_(2)`B. `Q_(1)=Q_(2)`C. `Q_(1) lt Q_(2)`D. `Q_(1) gt Q_(2)`
Answer» Correct Answer - B

Discussion

155.	The equation `4H^(+) rarr _(2)^(4) He^(2+) + 2e bar + 26 MeV represents`A. FusionB. FissionC. `b`-decayD. `g`-decay
Answer» Correct Answer - A

Discussion

156.	In the carbon cycle from which stars hotter than the sun obtain their energy the `._(6)C^(12)` isotopeA. slpits into three alpha particlesB. fuse with another `._(6)C^(12)` nucleus to form `._(12)Mg^(24)`C. is completely converted into energyD. is regenerated at the end of the cycle
Answer» Correct Answer - D

Discussion

157.	Energy is released from stars due to nuclear fusion taking place in two cycles proton-proton cycle and carbon nitrogen cycle. In these cycles four hydrogen nuclei combine to from helium nucleus. In this fusion reaction in addition to energy how many number of nutrinous are released ?
Answer» Correct Answer - 2 In nuclear fusion 2 positrons and 2 nuetrinos are released

Discussion

158.	The nucleus finally formed in fusion of protons in proton-proton cycle is that ofA. Heavy hydrogenB. CarbonC. HeliumD. Lithium
Answer» Correct Answer - C

Discussion

159.	Nuclear fission can be explained byA. Optical model of the nucleusB. Shell model of nucleusC. Collective model of the nucleusD. Liquid drop model of the nucleus
Answer» Correct Answer - D

Discussion

160.	Energy in the sun is due toA. Fossil fuelsB. RadioactivityC. FissionD. Fusion
Answer» Correct Answer - D

Discussion

161.	The fusion of hydrogen into helium is more likely to take place:A. At high temperature and high pressureB. At high temperature and low pressureC. At low temperature and low pressureD. At low temperature and high pressure
Answer» Correct Answer - A

Discussion

162.	In the carbon cycle from which stars hotter than the sun obtain their energy the `._(6)C^(12)` isotopeA. splits up into three alpha particlesB. fuses with another `._(6)C^(12)` nucleons to from `._(12)Mg^(24)`C. is completely converted into energyD. is regenerated at the end of the cycle
Answer» Correct Answer - D

Discussion

163.	The overall process of carbon nitrogen fusion cycle results in the fission of `4` protons to yield helium nucleus and_____A. PositronB. two electronsC. two positronsD. An electron
Answer» Correct Answer - A

Discussion

164.	Source of solar energy can be said to be due to natural fusion in which hydrogen gets converted into helium with carbon serving as a natural catalyst. This carbon cycle was proposed byA. BetheB. YukawaC. FermiD. Soddy
Answer» Correct Answer - A

Discussion

165.	Nuclear fission and fusion can be explained on the basis of ________A. Einstein theory of relativityB. Einstein specific heat equationC. Einstein mass -energy relationD. Einstein photo electric equation
Answer» Correct Answer - C

Discussion

166.	In carbon-Nitrogen fusion cycle, protons are fused to from a helium nucleus, positrons and release some energy. The number of protons fused and the number of positrons released in this process respectively areA. `4,4`B. `4,2`C. `2,4`D. `4,6`
Answer» Correct Answer - B

Discussion

167.	Suppose India has a target of producing by `2020 AD, 200,000 MW` of electric power, ten percent of which was to be obtained from nuclear power plants. Suppose we are given that, on an avedrage, the efficiency of utilization(i.e conversion to electric energy) of thermal energy produced in a reactor was `25%`. How much amount of fissionable uranium would our country need per year by `2020`? Take the heat energy per fission of `.^(235)U` to be about `200 MeV`.
Answer» Required power form nuclear plants `10% of 2,00,000Mw=2xx10^(10)w` Required electric energy from nuclear plants in one year `=2xx10^(10)xx365xx24xx60xx60` `=2xx10^(10)xx3.15xx10^(7)= 6.30xx10^(7)J` Availibale electric energy per fission `25% of 200 MeV` `=50 MeV = 8xx10^(-12)J` Req.no. of fissions per year `=(6.30xx10^(17))/(8xx10^(-12))=0.7875xx10^(29)` Req. of moles of `U^(238)` `=(0.7875xx10^(29))/(6.023xx10^(23))=0.1307xx10^(6)` Required mass of `U^(238)=0.1307xx235xx10^(6)g` `=30.71xx10^(6) gm =30.71xx10^(6)xx10^(-3)g` `=0.03071xx10^(6) kg=3.071xx10^(4)kg`

Discussion

168.	Observe the following statements regarding isotones i) `.^(59)K_(19)` and `.^(40)Ca_(20)` are isotones ii) Nuclides having different atomic numbers `(z)` and mass number `(A)` but same number of neutrons `(n)` are called Isotones iii) `.^(19)F_(9)` and `.^(23)Na_(11)` are isotones The correct answer isA. i, ii and iii are correctB. only i and ii are correctC. only I and iii are correctD. only ii and iii are correct
Answer» Correct Answer - B

Discussion

169.	In the options given below, let `E` denote the rest mass energy of a nucleus and `n` a neutron. The correct option is:A. `E(._(9)^(236)U) gt E(._(53)^(137)I)+E(._(39)^(97)Y)+2E(n)`B. `E(._(9)^(236)U) lt E(._(53)^(137)I)+E(._(39)^(97)Y)+2E(n)`C. `E(._(92)^(236)U) lt E(._(56)^(140)Ba)+E(._(36)^(94)Kr)+2E(n)`D. `E(._(92)^(236)U) = E(._(56)^(140)Ba)+E(._(36)^(94)Kr)+2E(n)`
Answer» Correct Answer - A (a) Rest mass energy of `U` will be greater than the reat mass energy of nuclei into which it breaks. The consistituent nuclei and neutrons will have kinetic energy also, as a result of conservation of linear momentum.

Discussion

170.	A nucleus `._(Z)^(A)X` has mass represented by `m(A, Z)`. If `m_(p)` and `m_(n)` denote the mass of proton and neutron respectively and `BE` the blinding energy (in MeV), thenA. `BE=[m(A, Z)-Zm_(p)-(A-Z)m_(n)]C^(2)`B. `BE=[Zm_(p)+(A-Z)m_(n)-m(A, Z)]C^(2)`C. `BE=[Zm_(p)+Am_(n)-m(A, Z)]C^(2)`D. `BE=m(A, Z)-Zm_(p)-(A-Z)m_(n)`
Answer» Correct Answer - B

Discussion

171.	In the options given below, let `E` denote the rest mass energy of a nucleus and `n` a neutron. The correct option is:A. `E(._(92)^(236)U) gt E(._(53)^(137)I)+E(._(39)^(97)Y)+2E(n)`B. `E(._(92)^(236)U) lt E(._(53)^(137)I)+E(._(39)^(97)Y)+2E(n)`C. `E(._(92)^(236)U) lt E(._(56)^(140)Ba)+(._(36)^(94)Kr)+2E(n)`D. `E(._(92)^(236)U) = E(._(56)^(140)Ba)+(._(36)^(94)Kr)+2E(n)`
Answer» Correct Answer - A Since energy is released in a fission process, the rest mass energy must decreases.

Discussion

172.	Half-life of a radioactive substance A is `4 days`. The probability that a nuclear will decay in two half-lives isA. `(1)/(4)`B. `(3)/(4)`C. `(1)/(2)`D. `1`
Answer» Correct Answer - B Number of nuclei left after `2` half lives `=(N_(0))/(4)` probability of a nucleus decaying `=`no. of nuclei decayed `//`total no. `=(3N_(0)//4)/(N_(0))=(3)/(4)`

Discussion

173.	Helium nuclei combine to form an oxygen nucleus. The energy released in the reaction is if `m_(O)=15.9994 "amu"` and `m_(He)=4.0026 "amu"`A. `10.24 Me V`B. `0 Me V`C. `5.24 Me V`D. `4 Me V`
Answer» Correct Answer - A `Deltam= 4m_(He)-m_(0)` `Deltam= 0.01 "amu" " " DeltaE=DeltaMC^(2)=0` binding energy per`//`Nucleon`=176//16"amu"=10.24 meV`

Discussion

174.	The sun radiates energy in all directions. The average radiations received on the earth surface from the sun is `1.4 "kilowatt"//m^2`. The average earth-sun distance is `1.5 xx 10^11` meters. The mass lost by the sun per day is.A. `4.4 xx 10^9 kg`B. `7.6 xx 10^14 kg`C. `3.8 xx 10^12 kg`D. `3.8 xx 10^14 kg`
Answer» Correct Answer - D (d) Energy radiated `= 1.4 kW//m^2` `=1.4 kJ//sec m^2 = (1.4 kJ)/((1)/(86400) "day" m^2) = (1.4 xx 86400)/( "day" m^2)` Total energy radiated/day `=(4 pi(1.5 xx 10^11)^2 xx 1.4 xx 86400)/(1) (kJ)/("day") = E` `:. E = mc^2 rArr m = ( E)/(c^2)` `=(4 pi(1.5 xx 10^11)^2 xx 1.4 xx 86400)/((3 xx 10^8)^2) = 3.8 xx 10^14 kg`.

Discussion

175.	A radio nuclide `A_(1)` with decay constant `lambda_(1)` transforms into a radio nuclide `A_2` with decay constant `lambda_(2)`. Assuming that at the initial moment, the preparation contained only the radio nuclide `A_(1)` (a) Find the equation decribing accumulation of radio nuclide `A_(2)` with time. (b) Find the time interval after which the activity of radio nuclide `A_(2)` reaches its maximum value.A. `(ln (lambda_(2)//lambda_(1)))/(lambda_(2)-lambda_(1))`B. `(ln (lambda_(2)//lambda_(1)))/(lambda_(2)-lambda_(1))`C. `ln (lambda_(2)-lambda_(1))`D. none of these
Answer» Correct Answer - d Conserve the number of nucleons.

Discussion

176.	A radio nuclide `A_(1)` with decay constant `lambda_(1)` transforms into a radio nuclide `A_2` with decay constant `lambda_(2)`. Assuming that at the initial moment, the preparation contained only the radio nuclide `A_(1)` (a) Find the equation decribing accumulation of radio nuclide `A_(2)` with time. (b) Find the time interval after which the activity of radio nuclide `A_(2)` reaches its maximum value.
Answer» (a) This part has already been discussed in section on succesive disintegrations with the result. `N_(2) (t)=(lambda_(1) N_(0))/(lambda_(2) -lambda_(1))(e^(-lambda_(1)t -e^(-lambda_(2)t)))` (b) The activity of nuclide `A_(2)` is `lambda_(2) N_(2)`. This is mximum when `N_(2)` is maximum, i.e., when `dN_(2)//dt=0`, activity maximum. `(d[N_(2) (t)])/(dt)=(d)/(dt)[(lambda_(1) (N_(0)))/(lambda_(2) -lambda_(1))(e^(-lambda_(1)t -e^(-lambda_(2)t)))]` `(lambda_(1)N_(0))/(lamda_(2)-lambda_(1))(lambda_(1)e^(-lambda_(1)t)+lambda_(2)e^(-lambda_(2)t))=0` `e_((lambda_(1) -lambda_(2))) t=(lambda_(2))/(lambda_(1))` `t=(1n (lambda_(2))//lambda_(1))/(lambda_(2)-lambda_(1))` .

Discussion

177.	A sample of Uranium is a mixture of two isotopes `._(92)^(234)U` and `._(92)^(238)U` present in the ratio `10%` and `90%` by weight. The half lives of these isotopes are `2.5 xx10^(5)` years and `4.5 xx10^(5)` years respectively. Calculate the contribution to activity in percentage of each isotope in this sample.
Answer» Correct Answer - `[16.67% and 83.33 %]`

Discussion

178.	Find the kinetic energy of the `alpha` - particle emitted in the decay `^238 Pu rarr ^234 U + alpha`. The atomic masses needed are as following: `^238 Pu 238.04955 u` `^234 U 234.04095 u` `^4 He 4.002603 u`. Neglect any recoil of the residual nucleus.
Answer» Correct Answer - [5.58 MeV]

Discussion

179.	(a) Calculate the energy released if `.^(238)U` emits an `alpha` particle. (b) Calculate the energy to be supplied to `.^(238)U` if two protons and two neutrons are to be emitted one by one. The atomic masses are : `.^(238)U=238.0508` amu`" ".^(234)Th=234.04363` amu `" "._(2)^(4)He=4.0026` amu `._(0)^(1)=1.008665` amu `" "._(1)^(1)p=1.007276` amu
Answer» Correct Answer - [(a) 4.25 MeV; (b) 23 MeV]

Discussion

180.	An atom of mass number `15` and atomic number `7` captures an `alpha-`particle and then emits a proton. The mass number and atomic number of the resulting product will respectively be.A. 14 and 2 respectivelyB. 16 and 4 respectivelyC. 17 and 6 respectivelyD. 18 and 8 respectively
Answer» Correct Answer - D

Discussion

181.	If the nucleus of hydrogen fuses with a nucleus of lithium to form two helium nuclei, (a) write down the nuclear reaction equation (b) find the release of energy in joule per fusion (c) find the number of hydrogen atoms equired to generate 9.8 J Mass of hydrogen, lithium and helium atoms are 1.0078 amu, 7.017 amu and 4.0036 amu respectively.
Answer» Correct Answer - `[0.263 xx 10^(-11) J, 37.26 xx 10^(11)]`

Discussion

182.	The luminous dials of watches are usually made by mixing a zinc sulphide phosphor with an `alpha`-particles emitter. The mass of radium (mass number `226,half-life 1620 years`)that is needed to produce an average of `10` alpha`-particles per second for this purpose isA. `2.77 mg`B. `2.77 g`C. `2.77 xx10^(-23)g`D. `2.77 xx10^(-13)kg`
Answer» Correct Answer - d `\|(dN)/(dt)\|=lambdaN` number of radium nuceli in `m g =(N_(A)m)/(226)` Decay constant, `lambda =(0.693)/(t_(1//2)) =(0.693)/(1620 xx 3.16 xx10^(7))` `\|(dN)/(dt)\|=10=(0.693 xx 10^(23)m)/(226) xx (0.693)/(1620 xx 3.16 xx10^(7))` `:. m=(10 xx 226xx1620 xx 3.16 xx10^(7))/(6.02 xx 10^(23) xx0.693)` `=2.77 xx 10^(-10) g` `=2.77 xx 10^(-13) kg`.

Discussion

183.	The half life period of a sample is 100 second. If we take 40 gram of the radioactive sample, then after 400 second how much substance will be left undecayed ?A. 10 gramB. 5 gramC. 2.5 gramD. 1.25 gram
Answer» Correct Answer - C

Discussion

184.	The half-life of `K^40` is `1.30xx10^9` y. A sample if `1.00g` of pure `KCI` gives 160 counts `s^(-1)`.Calculate the relative abundance of `K^40`(fraction of `K^40`present ) in natural potassium .
Answer» Correct Answer - [0.12 %]

Discussion

185.	The count rate from `100cm^(3)` of a radioactive liquid is `c`. Some of this liquid is now discarded. The count rate of the remaining liquid is found to be `c//10` after three half-lives. The volume of the remaining liquid, in `cm^(3)`, isA. 20B. 40C. 60D. 80
Answer» Correct Answer - D

Discussion

186.	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`, th `n` the energy released isA. `25.8` MeVB. `23.6` MeVC. `19.2` MeVD. `30.2` MeV
Answer» Correct Answer - B

Discussion

187.	The energy in `MeV` is released due to transformation of `1 kg` mass completely into energy `(c = 3 xx 10^8 m//s)`.A. `7.625 xx 10 Mev`B. `10.5 xx 10^29 MeV`C. `2.8 xx 10^-28 MeV`D. `5.625 xx 10^29 MeV`
Answer» Correct Answer - D (d) `E = Delta mc^2 = 1 xx (3 xx 10^8) = 9 xx 10^10 J` `rArr E = (9 xx 10^16)/(1.6 xx 10^-19) = 5.625 xx 10^35 eV` =`5.625 xx 10^29 MeV`.

Discussion

188.	An atomic nucleus `._90 Th^232` emits several `alpha` and `beta` radiations and finally reduces to `._82 Pb^208`. It must have emitted.A. `6,4`B. `4,6`C. `8,6`D. `6,8`
Answer» Correct Answer - A `._(90)Th^(232)rarr._(82)Pb^(208)+6._(2)He^(4)+4._(-1)e^(0)`

Discussion

189.	What is the age of an ancient wooden piece if it is known that the specific activity of `C^(14)` nuclide in it amouts to `3//5` of that in fresh trees? Given: the half of `C` nuclide is `5570 years` and `log_(e)(5//3)=0.5` .A. `4112` yearsB. `2092` yearsC. `5570` yearsD. `2785` years
Answer» Correct Answer - A Activity of ancient wood `=3//5 x` activity of lately felled trees `rArr A(3)/(5)A_(0)=A_(0)e^(-lambda t)` Solve for time `t= ?`

Discussion

190.	What is the age of an ancient wooden piece if it is known that the specific activity of `C^(14)` nuclide in it amouts to `3//5` of that in fresh trees? Given: the half of `C` nuclide is `5570 years` and `log_(e)(5//3)=0.5` .
Answer» Correct Answer - `[4.1xx10^(3)" years"]`

Discussion

191.	A piece of ancient wood shows an activity of `3.9` disintergration per sec. per gram of `.^(14)C`. Calculate the age of the wood. `T_(1//2)` of `.^(14) C=5570` years. Activity of fresh `.^(14)C=15.6` disinteration per second per gram.
Answer» Correct Answer - [11140 yrs]

Discussion

192.	`4xx10^23`tritium atoms are contained in a vessel. The half-life of decay of trituim nuclei is 12.3 y. Find (a) the activity of the sample ,(b) the number of decays in the next 10 hours (c ) the number of decays in the next 6.15 y.A. `7xx10^(14)s^(-1)`B. `7xx10^(18)s^(-1)`C. `7xx10^(24)s^(-1)`D. `7xx10^(4)s^(-1)`
Answer» Correct Answer - A `A_(0)=lambdaN_(0)=(ln 2xx4xx10^(23))/(12.3xx365xx24xx60xx60)=7xx10^(14)//s`

Discussion

193.	A vessel of vloume `125 cm^3` contains tritium `(H^3,t_(1//2)=12.3 y)` at 500 kPa and 300 k. Calculate the activity of the gas.
Answer» Correct Answer - `[724 Ci]`

Discussion

194.	`4xx10^23`tritium atoms are contained in a vessel. The half-life of decay of trituim nuclei is 12.3 y. Find (a) the activity of the sample ,(b) the number of decays in the next 10 hours (c ) the number of decays in the next 6.15 y.
Answer» Correct Answer - `[7.146xx10^(14) dps, 2.57xx10^(19), 1.17xx10^(23)]`

Discussion

195.	Inside the sumA. Four nuclei of hydrogen combine to form two nuclei of heliumB. Four nuclei of hydrogen combine to form four nuclei of heliumC. Four nuclei of hydrogen combine to form one nucleus of heliumD. Four nuclei of hydrogen is transformed into one nucleus of helium
Answer» Correct Answer - C

Discussion

196.	As the age of star increasesA. Helium quantity increasesB. Helium quantitiy decreasesC. Helium quantity does not changeD. Helium, Hydrogen both quantities increases
Answer» Correct Answer - A

Discussion

197.	The power radiated by a star and its mass ma are related by `(P)/(P_(0))=((m)/(M_(0)))^(7//2)` where `P_(0)` and `M_(0)` are power radiated by the Sun and mass of the Sun respectively. Assume that the fraction of mass lost by the star since its birth is `alpha(ltlt1)`. Calculate the age of the star in terms of `alpha,M_(0)P` and `P_(0)`.
Answer» Correct Answer - `(alphaM_(0)c^(2))/(p_(0)^(2//7)P^(5//7))`

Discussion

198.	Nuclei of radioactive element `A` are produced at rate `t^(2)` (where `t` is time) at any time `t`. The element `A` has decay constant `lambda`. Let `N` be the number of nuclei of element `A` at any time `t`. At time `t=t_(0), dN//dt` is minimum. The number of nuclei of element `A` at time `t=t_(0)` is
Answer» Correct Answer - `(2t_(0)-lambdat_(0)^(2))/(lambda_(2))`

Discussion

199.	A radioactive element is produced in nuclear reactor at a constant rate R(=numbers of nuclei per second). Its half-life is `T_(1//2)`. How much time, in terms of `T_(1//2)`. Is required to produce 50% of the equilibrium quantity of the radioactive element? is the result dependent of R?
Answer» Correct Answer - `T_(1//2)`,No

Discussion

200.	A radioactive material of half-life `T` was kept in a nuclear reactor at two different instants. The quantity kept second time was twice of the kept first time. If now their present activities are `A_1` and `A_2` respectively, then their age difference equalsA. `T/(ln2)\| l n (2A_(1))/(A_(2))\|`B. `T\|l n(A_(1))/(A_(2))\|`C. `T/(ln2)\|l n(A_(2))/(2A_(1))\|`D. `T ln \|A_(2)/(2A_(1))\|`
Answer» Correct Answer - C

Discussion

Explore topic-wise InterviewSolutions in .

From the following equation pick out the possible nuclear fusion reactionsA. `._6C^(13) +._1H^1 rarr ._6C^(14) +4.3MeV`B. `._6C^(13) +._1H^1 rarr ._7C^(13) +2MeV`C. `._7C^(14) +._1H^1 rarr ._8O^(15) +7.3MeV`D. `._(92)U^(235)+._(0)n^1`

Fusion reaction is initiated with the help ofA. low temperatureB. high temperatureC. neutronsD. any particle

The `(B.E)/(A)` for deutron and an `alpha`-particle are `X_(1)` and `X_(2)` respectively. The energy released `alpha`-particle isA. `4(X_(2)-X_(1))`B. `2(X_(2)-X_(1))`C. `4(X_(2)+X_(1))`D. `(X_(2)-X_(1))/(4)`

If `Q_(1)` and `Q_(2)` are the energies released in the fusion of hydrogen in Carbon-nitrogen cycle and proton-proton cycle respectively then cycle repespectively thenA. `Q_(1) gt Q_(2)`B. `Q_(1)=Q_(2)`C. `Q_(1) lt Q_(2)`D. `Q_(1) gt Q_(2)`

The equation `4H^(+) rarr _(2)^(4) He^(2+) + 2e bar + 26 MeV represents`A. FusionB. FissionC. `b`-decayD. `g`-decay

In the carbon cycle from which stars hotter than the sun obtain their energy the `._(6)C^(12)` isotopeA. slpits into three alpha particlesB. fuse with another `._(6)C^(12)` nucleus to form `._(12)Mg^(24)`C. is completely converted into energyD. is regenerated at the end of the cycle

Energy is released from stars due to nuclear fusion taking place in two cycles proton-proton cycle and carbon nitrogen cycle. In these cycles four hydrogen nuclei combine to from helium nucleus. In this fusion reaction in addition to energy how many number of nutrinous are released ?

The nucleus finally formed in fusion of protons in proton-proton cycle is that ofA. Heavy hydrogenB. CarbonC. HeliumD. Lithium

Nuclear fission can be explained byA. Optical model of the nucleusB. Shell model of nucleusC. Collective model of the nucleusD. Liquid drop model of the nucleus

Energy in the sun is due toA. Fossil fuelsB. RadioactivityC. FissionD. Fusion

The fusion of hydrogen into helium is more likely to take place:A. At high temperature and high pressureB. At high temperature and low pressureC. At low temperature and low pressureD. At low temperature and high pressure

In the carbon cycle from which stars hotter than the sun obtain their energy the `._(6)C^(12)` isotopeA. splits up into three alpha particlesB. fuses with another `._(6)C^(12)` nucleons to from `._(12)Mg^(24)`C. is completely converted into energyD. is regenerated at the end of the cycle

The overall process of carbon nitrogen fusion cycle results in the fission of `4` protons to yield helium nucleus and_____A. PositronB. two electronsC. two positronsD. An electron

Source of solar energy can be said to be due to natural fusion in which hydrogen gets converted into helium with carbon serving as a natural catalyst. This carbon cycle was proposed byA. BetheB. YukawaC. FermiD. Soddy

Nuclear fission and fusion can be explained on the basis of ________A. Einstein theory of relativityB. Einstein specific heat equationC. Einstein mass -energy relationD. Einstein photo electric equation

In carbon-Nitrogen fusion cycle, protons are fused to from a helium nucleus, positrons and release some energy. The number of protons fused and the number of positrons released in this process respectively areA. `4,4`B. `4,2`C. `2,4`D. `4,6`

Half-life of a radioactive substance A is `4 days`. The probability that a nuclear will decay in two half-lives isA. `(1)/(4)`B. `(3)/(4)`C. `(1)/(2)`D. `1`

Helium nuclei combine to form an oxygen nucleus. The energy released in the reaction is if `m_(O)=15.9994 "amu"` and `m_(He)=4.0026 "amu"`A. `10.24 Me V`B. `0 Me V`C. `5.24 Me V`D. `4 Me V`

Find the kinetic energy of the `alpha` - particle emitted in the decay `^238 Pu rarr ^234 U + alpha`. The atomic masses needed are as following: `^238 Pu 238.04955 u` `^234 U 234.04095 u` `^4 He 4.002603 u`. Neglect any recoil of the residual nucleus.

An atom of mass number `15` and atomic number `7` captures an `alpha-`particle and then emits a proton. The mass number and atomic number of the resulting product will respectively be.A. 14 and 2 respectivelyB. 16 and 4 respectivelyC. 17 and 6 respectivelyD. 18 and 8 respectively

The half life period of a sample is 100 second. If we take 40 gram of the radioactive sample, then after 400 second how much substance will be left undecayed ?A. 10 gramB. 5 gramC. 2.5 gramD. 1.25 gram

The half-life of `K^40` is `1.30xx10^9` y. A sample if `1.00g` of pure `KCI` gives 160 counts `s^(-1)`.Calculate the relative abundance of `K^40`(fraction of `K^40`present ) in natural potassium .

The count rate from `100cm^(3)` of a radioactive liquid is `c`. Some of this liquid is now discarded. The count rate of the remaining liquid is found to be `c//10` after three half-lives. The volume of the remaining liquid, in `cm^(3)`, isA. 20B. 40C. 60D. 80

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`, th `n` the energy released isA. `25.8` MeVB. `23.6` MeVC. `19.2` MeVD. `30.2` MeV

The energy in `MeV` is released due to transformation of `1 kg` mass completely into energy `(c = 3 xx 10^8 m//s)`.A. `7.625 xx 10 Mev`B. `10.5 xx 10^29 MeV`C. `2.8 xx 10^-28 MeV`D. `5.625 xx 10^29 MeV`

An atomic nucleus `._90 Th^232` emits several `alpha` and `beta` radiations and finally reduces to `._82 Pb^208`. It must have emitted.A. `6,4`B. `4,6`C. `8,6`D. `6,8`

What is the age of an ancient wooden piece if it is known that the specific activity of `C^(14)` nuclide in it amouts to `3//5` of that in fresh trees? Given: the half of `C` nuclide is `5570 years` and `log_(e)(5//3)=0.5` .A. `4112` yearsB. `2092` yearsC. `5570` yearsD. `2785` years

What is the age of an ancient wooden piece if it is known that the specific activity of `C^(14)` nuclide in it amouts to `3//5` of that in fresh trees? Given: the half of `C` nuclide is `5570 years` and `log_(e)(5//3)=0.5` .

A piece of ancient wood shows an activity of `3.9` disintergration per sec. per gram of `.^(14)C`. Calculate the age of the wood. `T_(1//2)` of `.^(14) C=5570` years. Activity of fresh `.^(14)C=15.6` disinteration per second per gram.

A vessel of vloume `125 cm^3` contains tritium `(H^3,t_(1//2)=12.3 y)` at 500 kPa and 300 k. Calculate the activity of the gas.

`4xx10^23`tritium atoms are contained in a vessel. The half-life of decay of trituim nuclei is 12.3 y. Find (a) the activity of the sample ,(b) the number of decays in the next 10 hours (c ) the number of decays in the next 6.15 y.

Inside the sumA. Four nuclei of hydrogen combine to form two nuclei of heliumB. Four nuclei of hydrogen combine to form four nuclei of heliumC. Four nuclei of hydrogen combine to form one nucleus of heliumD. Four nuclei of hydrogen is transformed into one nucleus of helium

As the age of star increasesA. Helium quantity increasesB. Helium quantitiy decreasesC. Helium quantity does not changeD. Helium, Hydrogen both quantities increases

A radioactive element is produced in nuclear reactor at a constant rate R(=numbers of nuclei per second). Its half-life is `T_(1//2)`. How much time, in terms of `T_(1//2)`. Is required to produce 50% of the equilibrium quantity of the radioactive element? is the result dependent of R?