873 + Interview Questions in NUCLEAR-PHYSICS IN GENERAL AWARENESS Page 10 InterviewSolution

451.	Which of the following isotopes is more stable and why? (a) `._(3)^(7)Li` or `._(3)^(8)Li` (b) `._(6)^(13)C` or `_(6)^(15)C` (c) What kind of decay will be shown by the unstable nuclei in the above sets (a) and (b)?
Answer» Correct Answer - (a) `._(3)^(7)Li` (b) `._(6)^(13)C` (c) `._(3)^(8)Lirarr` negaive `beta` decay; `._(6)^(15)Crarr` negative `beta` decay

Discussion

452.	Fusion reaction takes place at high temperature becauseA. atoms get ionized at high temperatureB. molecules get decomposed at high temperatureC. nuclei get decomposed at high temperatureD. due to their energy nuclei overcome their mutual repulsion and combines
Answer» Correct Answer - D

Discussion

453.	The figure shows a plot of number of neutron (N) versus number of protons (z) in all stable nuclei found in nature. What kind of decay are nuclei X,Y and Z expected to show?
Answer» Correct Answer - `Xrarr` negative `beta` decay `Yrarr` positron emission `Zrarr` alpha decay

Discussion

454.	Which of the following is not correct about nuclear forces?A. these are the strongest among forcesB. these are short range forceC. these are charge independent forcesD. all of the above
Answer» Correct Answer - D

Discussion

455.	In most stable nuclei neutron number N and proton number Z has the relationA. `N lt Z`B. N=ZC. `N gt Z`D. N`ge` Z
Answer» Correct Answer - D

Discussion

456.	Among the following, short ranges, charge independent and spin dependent forces areA. Gravitational forcesB. Nuclear forcesC. Electromagntic forcesD. Weak forces
Answer» Correct Answer - B

Discussion

457.	Two protons are kept at a separation of `10 nm`. Let `F_n and F_e` be the nuclear force and the electromagnetic force between them.A. `F_(e ) = F_(n)`B. `F_(e ) gt gt F_(n)`C. `F_(e ) lt lt F_(n)`D. `F_(n)=3F_(e )`
Answer» Correct Answer - C

Discussion

458.	Two protons are kept at a separation of `10 nm`. Let `F_n and F_e` be the nuclear force and the electromagnetic force between them.A. `F_(e) = F_(n)`B. `F_(e) gt gt F_(n)`C. `F_(e) lt lt F_(n)`D. `F_(e)` and `F_(n)` duffer slightly
Answer» Correct Answer - B

Discussion

459.	Which of the following is not correct about nuclear forces?A. They are short range attractive forcesB. They are changes to repulsion at very close distanceC. They change to repulsion at very close distanceD. They obey inverse square law
Answer» Correct Answer - D

Discussion

460.	Identify the correct statement`//`statements a) At greater distances nuclear forces are negligible b) Nuclear forces are non central forces c) Nuclear forces are weakest in nature d)Nuclear forces are charge dependent forcesA. a,bB. b,cC. c,dD. a,d
Answer» Correct Answer - A

Discussion

461.	Nuclear forces are.A. Non-central forcesB. saturatedC. Spin dependentD. All of the above
Answer» Correct Answer - D

Discussion

462.	Two protons attract each other whenA. the distance between them is `10^(-10)m`B. the distance between them is `10^(-1)m`C. the distance between them is `10^(-15)m`D. the distance between them is `10^(-6)m`
Answer» Correct Answer - C

Discussion

463.	Among the following interactions one is of least significant in nuclear physics isA. nuclear interactionB. gravitational interactionC. electrostatic interactionD. electromagnetic interaction
Answer» Correct Answer - B

Discussion

464.	Among gravitational, electrostatic and nuclear forces, the two attractive forces between two neutrons areA. Electrostatic and nuclearB. Electrostatic and gravitationalC. Gravitational and nuclearD. Electrostatic
Answer» Correct Answer - C

Discussion

465.	Which of the follwing is formed by decay of a free neutron?A. A number of electronsB. Two protonsC. a proton and an electronD. An `alpha`-particle
Answer» Correct Answer - C

Discussion

466.	The most penetrating atom smashing particles isA. neutronB. protonC. alpha particleD. deuteron
Answer» Correct Answer - A

Discussion

467.	Neutron was discovered by the experiment ofA. Artificial transmutation of `(._(4)Be^(9))` by `alpha`-particlesB. Artificial transmutation of`(._(7)N^(11))` by `alpha`-particlesC. Rutherford scattering of alpha particles by heavy nucleiD. Beqerel with radio activity
Answer» Correct Answer - A

Discussion

468.	The average life of an isolated neutrons isA. `1500 s`B. `1000 s`C. `1200 s`D. `3` minutes
Answer» Correct Answer - B

Discussion

469.	Slow neutron are sometimes refer to as thermal neutrons becauseA. neutron being heatedB. the energy of these neutrons is equal to the energy of neutrons in a heated atomC. these neutrons have energy of neutrons in a neutron has at normal temperatureD. such neutrons gather energy released in the fission process
Answer» Correct Answer - C

Discussion

470.	The energy of thermal neutrons isA. ` lt 1 eV`B. ` gt 1 eV`C. `=2 Mev`D. `=4 MeV`
Answer» Correct Answer - A

Discussion

471.	Slow neutron are sometimes refer to as thermal neutrons becauseA. they are short heart radiationsB. they are in thermal equilibriumC. they are capable of generating heatD. their energies are of same order as that of molecule enrgies at ambient temperatures.
Answer» Correct Answer - D

Discussion

472.	In neutron discovery experiment,`Be` is bombarded withA. ProtonsB. Alpha particlesC. NeutronsD. Deutrons
Answer» Correct Answer - B

Discussion

473.	Thermal neutrons areA. prompt neutronsB. Slow neutronsC. Neutrons which are in the nucleusD. Neutrons from the sun
Answer» Correct Answer - B

Discussion

474.	In neutron discovery experiment,`Be` is bombarded withA. ProtonB. DeutronsC. `alpha`-particleD. `beta`-particle
Answer» Correct Answer - C

Discussion

475.	The process of producing a new stable nucleus from the other stable nucleus is calledA. Nuclear reactionB. Artificial transmutationC. Nuclear fusionD. Nuclear fission
Answer» Correct Answer - B

Discussion

476.	STATEMENT-I: It is possible for a thermal neutron to be absorbed by a nucleus where as proton or an alpha particle would need a much larger amount of energy for being absorbed by the same nucleus. STATEMENT-II: Neutron is electically neutral but proton and alpha particle are positively charged.A. Statement-1 is True, Statement-2 is Ture, Statement-2 is correct explanation for Statement-3B. Statement-1 is Ture, Statement-2 is True, Statement-2 is NOT a correct explanation for Statement-1.C. Statement-1 is True, Statement -2 is FalseD. Statement-1 is False, Statement-2 is True.
Answer» Correct Answer - A Nuclear force

Discussion

477.	STATEMENT-I: Consider the following nuclear reaction of an ustable `._(6)^(14)C rarr ._(7)^(14)N + _(-1)^(0)e+ overset(-)v`. In a nuclear reaction total energy and momentum is conserved experiments show that the electrons are emitted with a continous range of kinetic energies upto some maximum value. STATEMENT-II: Remaining energy is released as thermal energy.A. Statement-1 is True, Statement-2 is Ture, Statement-2 is correct explanation for Statement-4B. Statement-1 is Ture, Statement-2 is True, Statement-2 is NOT a correct explanation for Statement-1.C. Statement-1 is True, Statement -2 is FalseD. Statement-1 is False, Statement-2 is True.
Answer» Correct Answer - C Binding energy

Discussion

478.	At least how many thermal neutrons should be available to strat a fission reactionA. `2`B. `3`C. `1`D. `4`
Answer» Correct Answer - C

Discussion

479.	Ustable fission fragments decay by emitting neutrons and electrons, neutrons so emitted are calledA. prompt neutronsB. delayed neutonsC. stray neutronsD. sustained neutrons
Answer» Correct Answer - B

Discussion

480.	If the neutrons reproduction factor `K` is a) greater than `1` the fission rection is accelerated b)less than `1` the fission reaction retards c) equal to `1` the fission reaction is at steady stateA. onlu `a,b` are tureB. only `b,c` are trueC. only `a,c` are trueD. only `a,b,c` true
Answer» Correct Answer - D

Discussion

481.	The product of the fission of `U^(235)` by thermal neutron areA. `Ba^(141)` and `Kr^(92)` and `3` neutron alwaysB. `Xe^(140), Sr^(94)` and `2_(0)n^(1)` alwaysC. can be different in each fissionD. should have same mass number
Answer» Correct Answer - C

Discussion

482.	Among the following one is wrongA. The energy of thermal neutrons is about `25 me V`B. In a nuclear reaction, when neutrons multiplication factor, `K=1` then the reaction is said to be criticalC. `._(92)U^(235)` undergoes fission by bombardment of high energy neutronD. On average `2.5` neutrons are emitted per fission of `._(92)U^(235)`
Answer» Correct Answer - C

Discussion

483.	Assertion `(A)` : Fragments produced in the fission of `U^(235)` are radioactive. Reason `(R )` : The fragments have abnormally high proton to neutron ratioA. Both `A` and `R` are true and `R` is correct explanation of `A`B. Both `A` and `R` are true and `R` is not correct explanation of `A`C. `A` is true but `R` is falseD. `A` is false but `R` is true.
Answer» Correct Answer - C

Discussion

484.	When `1 gm` of `U^(235)` is completely annihilated energy liberated is `E_(1)` and when `1 gm` of `U^(235)` completely undergoes fission the energy liberated is `E_(2)`, thenA. `E_(1) gt E_(2)`B. `E_(1)=E_(2)`C. `E_(1) lt E_(2)`D. `E_(1) le E_(2)`
Answer» Correct Answer - A

Discussion

485.	In the process of fission, the binding energy per nucleonA. IncreasesB. DecreasesC. Remains unchangedD. Increases for mass number `A lt 56` nuclei but decreases for mass number `A gt 56`
Answer» Correct Answer - A

Discussion

486.	In a critical chain reactionA. energy is released at increasing areB. energy is released at steady rateC. energy is released at decreasing rateD. energy is not released
Answer» Correct Answer - B

Discussion

487.	Nuclear energy is released in fission since binding energy per nucleon isA. smaller for fission fragments than for parent nucleusB. the same for fission fragments and parent nucleusC. larger for fission fragements than for parent nucleusD. sometimes large and sometimes smaller
Answer» Correct Answer - C

Discussion

488.	A nuclear explosion is designed to deliver `1 MW` of heat energy, how many fission events must be required in a second to attain this power level. If this explosion is designed with a nuclear fuel consisting of uranium `235` to run a reactor at this power level for one year, then calculate the amount of fuel needed. You can assume that the calculate the amount of energy released per fission event is `200 MeV`.
Answer» Correct Answer - `[3.125 xx 10^(16), 384.5 g]`

Discussion

489.	When `._(92)U^(235)U` undergoes fission. About `0.1%` of the original mass is converted into energy. Then the amount of `._(92)U^(235)` should undergo fission per day in a nuclear reactor so that it provides energy of 200 mega watt electric power isA. `9.6xx10^(-2) kg`B. `4.8xx10^(-2)kg`C. `19.2xx10^(-2)kg`D. `1.2xx10^(-2)kg`
Answer» Correct Answer - C `E=MC^(2)`

Discussion

490.	In nuclear fission , `0.1%` mass in converted into energy. The energy released in the fission of `1 Kg` mass isA. `2.5xx10^(5) KWH`B. `2.5xx10^(7) KWH`C. `2.5xx10^(9) KWH`D. `2.5xx10^(-7) KWH`
Answer» Correct Answer - B `e=(0.1)/(100)MC^(2)`, in `kwh=(E )/(36xx10^(5))`

Discussion

491.	In nuclear fission `0.1%` mass is converted into energy How much electrical energy can be generated by the fission of 1 kg of fuel ?A. 1 kWhB. `10^(7)` kWhC. 2.5 kWhD. `2.5xx10^(7)` kWh
Answer» Correct Answer - D

Discussion

492.	In fission,the percentage of mass converted into energy is aboutA. `0.01%`B. `0.1%`C. `1%`D. `10%`
Answer» Correct Answer - D

Discussion

493.	If mass of the fissionable material is less than the critical mass, thenA. fission and chain reaction both are impossibleB. fission is possible but chain reaction is impossibleC. fission is impossible but chain reaction is possibleD. fission and chain reaction both are possible.
Answer» Correct Answer - A

Discussion

494.	The critical mass of a fissionable material isA. 75 kgB. 1kgC. 20 kgD. 10 kg
Answer» Correct Answer - B

Discussion

495.	The critical mass of a fissionable uranium `-235` can be reduced byA. adding impuritiesB. heating materialC. surrounding it by a neutron-reflecting materialD. surrounding it by a neutron-absorbing material
Answer» Correct Answer - C

Discussion

496.	`._(92)U^(238)rarr._(82)Pb^(206)+8._(2)^(4)He`. The number of `beta` particles releaased in this reaction isA. `6`B. `3`C. `1`D. `10`
Answer» Correct Answer - A

Discussion

497.	The age of pottery is determind by archeologists using a radiosotope ofA. carbonB. cobaltC. iodineD. phosphorus
Answer» Correct Answer - A

Discussion

498.	For fast chain reaction, the size of `U^(235)` block, as compared to its critical size, must beA. greaterB. smallerC. sameD. anything
Answer» Correct Answer - A

Discussion

499.	In a nuclear reaction some mass converts into energy. In this reaction total `B.E` of reactants when compared with that of product isA. always greaterB. always lesC. either greater or lessD. always equal
Answer» Correct Answer - D

Discussion

500.	The half-life of a radioactive isotope is `3` hours. The value of its disintegration constant isA. `0.3 "hour"^(-1)`B. `0.693 "hour"^(-1)`C. `0.231 "hour"^(-1)`D. `0.231 "min"^(-1)`
Answer» Correct Answer - C

Discussion

Explore topic-wise InterviewSolutions in .

Which of the following isotopes is more stable and why? (a) `._(3)^(7)Li` or `._(3)^(8)Li` (b) `._(6)^(13)C` or `_(6)^(15)C` (c) What kind of decay will be shown by the unstable nuclei in the above sets (a) and (b)?

Fusion reaction takes place at high temperature becauseA. atoms get ionized at high temperatureB. molecules get decomposed at high temperatureC. nuclei get decomposed at high temperatureD. due to their energy nuclei overcome their mutual repulsion and combines

The figure shows a plot of number of neutron (N) versus number of protons (z) in all stable nuclei found in nature. What kind of decay are nuclei X,Y and Z expected to show?

Which of the following is not correct about nuclear forces?A. these are the strongest among forcesB. these are short range forceC. these are charge independent forcesD. all of the above

In most stable nuclei neutron number N and proton number Z has the relationA. `N lt Z`B. N=ZC. `N gt Z`D. N`ge` Z

Among the following, short ranges, charge independent and spin dependent forces areA. Gravitational forcesB. Nuclear forcesC. Electromagntic forcesD. Weak forces

Two protons are kept at a separation of `10 nm`. Let `F_n and F_e` be the nuclear force and the electromagnetic force between them.A. `F_(e ) = F_(n)`B. `F_(e ) gt gt F_(n)`C. `F_(e ) lt lt F_(n)`D. `F_(n)=3F_(e )`

Two protons are kept at a separation of `10 nm`. Let `F_n and F_e` be the nuclear force and the electromagnetic force between them.A. `F_(e) = F_(n)`B. `F_(e) gt gt F_(n)`C. `F_(e) lt lt F_(n)`D. `F_(e)` and `F_(n)` duffer slightly

Which of the following is not correct about nuclear forces?A. They are short range attractive forcesB. They are changes to repulsion at very close distanceC. They change to repulsion at very close distanceD. They obey inverse square law

Identify the correct statement`//`statements a) At greater distances nuclear forces are negligible b) Nuclear forces are non central forces c) Nuclear forces are weakest in nature d)Nuclear forces are charge dependent forcesA. a,bB. b,cC. c,dD. a,d

Nuclear forces are.A. Non-central forcesB. saturatedC. Spin dependentD. All of the above

Two protons attract each other whenA. the distance between them is `10^(-10)m`B. the distance between them is `10^(-1)m`C. the distance between them is `10^(-15)m`D. the distance between them is `10^(-6)m`

Among the following interactions one is of least significant in nuclear physics isA. nuclear interactionB. gravitational interactionC. electrostatic interactionD. electromagnetic interaction

Among gravitational, electrostatic and nuclear forces, the two attractive forces between two neutrons areA. Electrostatic and nuclearB. Electrostatic and gravitationalC. Gravitational and nuclearD. Electrostatic

Which of the follwing is formed by decay of a free neutron?A. A number of electronsB. Two protonsC. a proton and an electronD. An `alpha`-particle

The most penetrating atom smashing particles isA. neutronB. protonC. alpha particleD. deuteron

Neutron was discovered by the experiment ofA. Artificial transmutation of `(._(4)Be^(9))` by `alpha`-particlesB. Artificial transmutation of`(._(7)N^(11))` by `alpha`-particlesC. Rutherford scattering of alpha particles by heavy nucleiD. Beqerel with radio activity

The average life of an isolated neutrons isA. `1500 s`B. `1000 s`C. `1200 s`D. `3` minutes

The energy of thermal neutrons isA. ` lt 1 eV`B. ` gt 1 eV`C. `=2 Mev`D. `=4 MeV`

Slow neutron are sometimes refer to as thermal neutrons becauseA. they are short heart radiationsB. they are in thermal equilibriumC. they are capable of generating heatD. their energies are of same order as that of molecule enrgies at ambient temperatures.

In neutron discovery experiment,`Be` is bombarded withA. ProtonsB. Alpha particlesC. NeutronsD. Deutrons

Thermal neutrons areA. prompt neutronsB. Slow neutronsC. Neutrons which are in the nucleusD. Neutrons from the sun

In neutron discovery experiment,`Be` is bombarded withA. ProtonB. DeutronsC. `alpha`-particleD. `beta`-particle

The process of producing a new stable nucleus from the other stable nucleus is calledA. Nuclear reactionB. Artificial transmutationC. Nuclear fusionD. Nuclear fission

At least how many thermal neutrons should be available to strat a fission reactionA. `2`B. `3`C. `1`D. `4`

Ustable fission fragments decay by emitting neutrons and electrons, neutrons so emitted are calledA. prompt neutronsB. delayed neutonsC. stray neutronsD. sustained neutrons

If the neutrons reproduction factor `K` is a) greater than `1` the fission rection is accelerated b)less than `1` the fission reaction retards c) equal to `1` the fission reaction is at steady stateA. onlu `a,b` are tureB. only `b,c` are trueC. only `a,c` are trueD. only `a,b,c` true

The product of the fission of `U^(235)` by thermal neutron areA. `Ba^(141)` and `Kr^(92)` and `3` neutron alwaysB. `Xe^(140), Sr^(94)` and `2_(0)n^(1)` alwaysC. can be different in each fissionD. should have same mass number

When `1 gm` of `U^(235)` is completely annihilated energy liberated is `E_(1)` and when `1 gm` of `U^(235)` completely undergoes fission the energy liberated is `E_(2)`, thenA. `E_(1) gt E_(2)`B. `E_(1)=E_(2)`C. `E_(1) lt E_(2)`D. `E_(1) le E_(2)`

In the process of fission, the binding energy per nucleonA. IncreasesB. DecreasesC. Remains unchangedD. Increases for mass number `A lt 56` nuclei but decreases for mass number `A gt 56`

In a critical chain reactionA. energy is released at increasing areB. energy is released at steady rateC. energy is released at decreasing rateD. energy is not released

Nuclear energy is released in fission since binding energy per nucleon isA. smaller for fission fragments than for parent nucleusB. the same for fission fragments and parent nucleusC. larger for fission fragements than for parent nucleusD. sometimes large and sometimes smaller

In nuclear fission , `0.1%` mass in converted into energy. The energy released in the fission of `1 Kg` mass isA. `2.5xx10^(5) KWH`B. `2.5xx10^(7) KWH`C. `2.5xx10^(9) KWH`D. `2.5xx10^(-7) KWH`

In nuclear fission `0.1%` mass is converted into energy How much electrical energy can be generated by the fission of 1 kg of fuel ?A. 1 kWhB. `10^(7)` kWhC. 2.5 kWhD. `2.5xx10^(7)` kWh

In fission,the percentage of mass converted into energy is aboutA. `0.01%`B. `0.1%`C. `1%`D. `10%`

If mass of the fissionable material is less than the critical mass, thenA. fission and chain reaction both are impossibleB. fission is possible but chain reaction is impossibleC. fission is impossible but chain reaction is possibleD. fission and chain reaction both are possible.

The critical mass of a fissionable material isA. 75 kgB. 1kgC. 20 kgD. 10 kg

The critical mass of a fissionable uranium `-235` can be reduced byA. adding impuritiesB. heating materialC. surrounding it by a neutron-reflecting materialD. surrounding it by a neutron-absorbing material

`._(92)U^(238)rarr._(82)Pb^(206)+8._(2)^(4)He`. The number of `beta` particles releaased in this reaction isA. `6`B. `3`C. `1`D. `10`

The age of pottery is determind by archeologists using a radiosotope ofA. carbonB. cobaltC. iodineD. phosphorus

For fast chain reaction, the size of `U^(235)` block, as compared to its critical size, must beA. greaterB. smallerC. sameD. anything

In a nuclear reaction some mass converts into energy. In this reaction total `B.E` of reactants when compared with that of product isA. always greaterB. always lesC. either greater or lessD. always equal

The half-life of a radioactive isotope is `3` hours. The value of its disintegration constant isA. `0.3 "hour"^(-1)`B. `0.693 "hour"^(-1)`C. `0.231 "hour"^(-1)`D. `0.231 "min"^(-1)`