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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 351. |
Difference in `._(17)Cl^(35) and ._(17)Cl^(37)` is ofA. Atomic numberB. Number of protonsC. Number of neutronsD. Number of electrons |
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Answer» Correct Answer - C Isotopes differ in mass number, and hence in the number of neutrons. |
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| 352. |
Given is the electronic configuration of element `X` `{:(K,L,M,N,),(2,8,11,2,):}` The number of electrons present with `l = 2` in an atom of element `X` is.A. `3`B. `6`C. `5`D. `4` |
| Answer» Correct Answer - A | |
| 353. |
The total spin resulting from a `d^7` configuration is :A. `1`B. `2`C. `5//2`D. `3//2` |
| Answer» Correct Answer - D | |
| 354. |
Calculate wavelength for `2^(nd)` line of Balmer series of `He^(+)` ion |
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Answer» `1/lambda=R(2)^(2)[1/n_(1)^(2)-1/n_(2)^(2)]` `n_(1)=2 n_(2)=4` `1/lambda=R(2^(2))[1/2^(2)-1/4^(2)]` `1/lambda=(3R)/(4) " " lambda=(4)/(3R)` Ans. |
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| 355. |
Which is least effective for artificial transmutatioA. DeuteronsB. NeutronsC. `alpha`-particlesD. Protons |
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Answer» Correct Answer - C Due to heavy mass `alpha-` particles can not easily pass through solid matter so they are less effective for artificial transmutation |
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| 356. |
A radio isotope will not emitA. Gamma and alpha rays simultaneouslyB. Gamma rays onlyC. Alpha and beta rays simultaneouslyD. Beta and gamma rays simultaneously |
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Answer» Correct Answer - B::C It is believed that when an `alpha " or " beta-` particle is emitted, the nuclear becomes excited, i.e., has higher energy and emits the excess energy in the form of radiation which form `gamma`-rays. But `alpha and beta` rays are not emitted simultaneously |
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| 357. |
In a nuclear reactor, chain reaction is controlled by introducingA. Iron rodB. Cadmium rodC. Graphite rodD. Platinum rod |
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Answer» Correct Answer - B Cd and boron rods are control rods used in reactors |
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| 358. |
In a chain reaction, uranium atom gets fissioned forming two different materials. The total weight of these put together isA. More than the weight of parent uranium atomB. Less than the weight of parent uranium atomC. More or less depends upon experimental conditionsD. Neither more nor less |
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Answer» Correct Answer - B Due to evolution of nuclear energy as a result of mass decays |
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| 359. |
Artificial elements have been prepared by bombardment reactions in high energy accelerators. What is the mass number of the element X produced in the following nuclear reaction `._(95)^(249)Cf + ._(7)^(15)N rarr ._(105)X + 4 ._(0)^(1)n`A. 261B. 264C. 260D. 257 |
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Answer» Correct Answer - C Equate atomic no. and mass no. |
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| 360. |
Cadmium rods are used for which purposeA. Emit electronsB. Absorb neutronsC. Emit neutronsD. Absorb electrons |
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Answer» Correct Answer - B Cadmium rods are used to absrob neutrons in nuclear reactors, because cadmium is neutron absorber. |
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| 361. |
What is the correct order of velocity of alpha `(alpha) and, " beta " (beta)` and gamma `(gamma)` raysA. `alpha gt beta gt gamma`B. `alpha gt gamma beta`C. `gamma gt alpha gt beta`D. `gamma gt beta gt alpha` |
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Answer» Correct Answer - D The velocity of `alpha`-rays are `~ (1)/(10)` th of that of light, that of `beta-`rays are `~(1)/(3) " to " (9)/(10)` th of that of light. The velocity of `gamma`-rays are same as that of light |
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| 362. |
`beta`-particle is emitted in radioactivity byA. Conversion of proton into neutronB. from outermost orbitC. conversion of neutron into protonD. `beta`-particle is not emitted |
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Answer» Correct Answer - c It is considered than `beta`-particle is emitted from the nucleus by the conversion of neutron into proton `._(0)n^(1) to ._(1)H^(1) + ._(-1)beta^(0)` |
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| 363. |
If` n//p` ratio is high, the nucleus tends to stabilize by `:`A. The emission of a `beta-` particleB. Neutron captureC. Losing a positronD. Any one of the above |
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Answer» Correct Answer - A `beta`- particle emission decreases `n//p` ratio. |
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| 364. |
A nuclear reaction is accompanied by loss of mass equivalent to 0.01864 amu. Energy liberated isA. 931 MeVB. `186.6` MeVC. 17.36 MeVD. 460 MeV |
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Answer» Correct Answer - C Energy liberated = loss of mass `xx 931` `= 0.01864 xx 931 = 17.36 MeV` |
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| 365. |
`._(88)X^(288) - 3alpha + beta rarr Y`. The element Y isA. `._(82) Pb^(216)`B. `._(82)Pb^(217)`C. `.(83)Bi^(218)`D. `._(83)Bi^(216)` |
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Answer» Correct Answer - D Atomic No.: `88 - (3 xx 2) + (1xx1) = 83` Mass No.: `228 - (3 xx4) - (1 xx0) = 216` |
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| 366. |
Radioactive substances emit `gamma`-rays, which areA. `+ve` charged particleB. `-ve` charged particleC. Massive particleD. Packet of energy |
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Answer» Correct Answer - D `gamma`-rays are neutral energy packet |
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| 367. |
`._(7)N^(13)` changes to `._(6)C^(13)` by the emission ofA. electronB. neutronC. positionD. proton |
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Answer» Correct Answer - c `._(7)N^(13) to ._(6)C^(13) + underset("Position")(._(1)e^(0))` Positron is an anti-particle of electron `(._(-1)e^(0))`. |
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| 368. |
The alpha particles areA. High`-` energy electronsB. Positively charged hydrogen ionsC. High`-` energy `X-` rays radiationsD. Double positively charged helium nuclei. |
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Answer» Correct Answer - D `alpha=underset(2)(4)He^(2+)` |
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| 369. |
Radium is a radioactive substance. It dissolves in dilute `H_(2)SO_(4)` and forms a compound radium sulphate. The compound isA. No longer radioactiveB. Half as radioactive as the radium contentC. As radioactive as the radium contentD. Twice as radioactive as the radium content. |
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Answer» Correct Answer - C Radioactivity does not depend upon the surrounding. |
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| 370. |
All radioactive elements which emit `beta-` rays have the same half `-` life periods. |
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Answer» Correct Answer - F |
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| 371. |
Which of the following does not characteristic X -rays ?A. Radiation can ionize gases.B. Radiation causes `ZnS` to fluorence.C. Deflected by electric and magnetic field.D. Wavelengths are shorter than those of ultraviolet rays. |
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Answer» Correct Answer - C Because `X-` rays are not charged particles. |
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| 372. |
The rays are given off by a radioactive element fromA. NucleusB. Valence electronsC. All the orbitsD. Outer orbit |
| Answer» Correct Answer - A | |
| 373. |
Which of the following does not characteristic X -rays ?A. The radiation can ionise the gasB. it causes fluresce effect on `ZnS`C. `Deflected by electric and magnetic fieldsD. Have wavelength shorter than ultraviolet rays |
| Answer» Correct Answer - C | |
| 374. |
The angular momentum of electron in a given orbit is J . Its kinetic energy will be :A. `1/2(J^(2))/(mr^(2))`B. `(Jv)/(r)`C. `(J^(2))/(2m)`D. `(J^(2))/(2pi)` |
| Answer» Correct Answer - A | |
| 375. |
Write equations for the following transformation: (a) `._(7)^(17)N (n, p)` (b) `._(19)^(39)K(n, alpha)` |
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Answer» Correct Answer - (a) `._(7)^(14)N+._(0)^(1)n rarr._(6)^(14)C+._(1)^(1)H` (b) `._(19)^(39)K+._(0)^(1)n rarr ._(17)^(36)Cl +._(2)^(4)He` (a) `_(7)^(14)N+ _(0)^(1)n to `_(6)^(14)C+_(1)^(1)H` (b) `_(19)^(39)K+_(0)^(1)n to `_(17)^(36)Cl+_(2)^(4)He` |
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| 376. |
Which of the following processes are feasible?A. `._(1)p^(1) + ._(0)n^(1) to ._(1)D^(2) + barv`B. `._(1)H^(1) + ._(-1)e^(0) to ._(0)n^(1)`C. `._(0)n^(1) to ._(1)p^(1) + ._(-1)e^(0) + barv`D. None of the above |
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Answer» Correct Answer - c The electron does not exist in the nucleus but it is formed at the time of emission and indicates as `._(0)n^(1) to ._(1)p^(1) + ._(-1)e^(0) + barv` |
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| 377. |
An oil drop has `6.39 xx 10^(-19)C` charge .How many electrons does this oil drop has ?A. `2`B. `4`C. `6`D. `8` |
| Answer» Correct Answer - B | |
| 378. |
`._(11)Na^(28)` is a radioactive and it decays toA. `._(12)Mg^(24)` and `beta`-particlesB. `._(11)Na^(21)` and neutronC. `._(13)F^(24)` and positronD. `._(9)F^(20)` and `alpha`-particles |
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Answer» Correct Answer - a `._(11)Na^(24)` is a radioactive isotope and it decays to `._(12)Mg^(24)` and `beta`-particles, which is shown as `._(11)Na^(24) to ._(12)Mg^(24) + ._(-1)beta^(0)` |
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| 379. |
The half-life of `Co^(60)` is 7 years. If one g of it decays, the amount of the substance remaining after 28 years isA. 0.25 gB. 0.125 gC. 0.0625 gD. 0.50 g |
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Answer» Correct Answer - C `n = (28)/(7) = 4, N = (N_(0))/(2^(n)), N = (1)/(2^(4)) = (1)/(16) = 0.0625 g` |
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| 380. |
Half-life of a radioactive substance is 120 days. After 480 days, 4 g will be reduced toA. 2B. 1C. 0.5D. 0.25 |
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Answer» Correct Answer - D `n = (480)/(120) = 4, N = (N_(0))/(2^(n)), N = (4)/(2^(4)) = (4)/(16) = 0.25 g` |
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| 381. |
A rock is found to contain U-238 and Pb-206 in the ratio of 3 : 2. If `t""_(1//2)` of U-238 is `4.5xx10""^(-9)` years. Calculate the age rock?A. `3.71xx10""^(-9)years`B. `3.71xx10""^(9)years`C. `31.7xx10""^(9)years`D. `3.71xx10""^(9)days` |
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Answer» Correct Answer - b `t=(2.303Xt""_(1//2))/(0.693)log.((1+pb""^(206))/(U""^(238)))` |
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| 382. |
If a nuclide of an element in group I A (1st group) undergoes radioactive decay be emitting `beta^(o+)`, what will be the periodic group of the resulting element? |
| Answer» In this case although `._(6)C^(16)` has even numbe of `p` and `n`. Still its `n//p` ratio is higher than `n//p` ratio of `._(7)N^(16)`. | |
| 383. |
Which of the following `"is"//"are"` correct when a nuclide of mass number `(A)` and atomic number `(Z)` undergoes radioactive process?A. Both `A` and `Z` decreases, the process is called `alpha`-decay.B. A remains unchanged and `Z` decreases by 1. The process is called `beta^(o+)` or positron decay of `K-`electron capture.C. Both `A` and `Z` remain unchanged, the process is called `gamma`-decay.D. Both `A` and `Z` increase, the process is called nuclear isomerism. |
| Answer» Correct Answer - A::B::C | |
| 384. |
Which of the following is/are correct?A. 1 Fermi=`10""^(3)`dpsB. 1 curie=`3.7xx10""^(10)` dpsC. 1 rutherford =`10""^(6)` dpsD. 1 becquerel=1 dps |
| Answer» Correct Answer - c,d | |
| 385. |
For nuclide `""_(Z)X""^(A)`, which of the following changes snot take place in respective decay:A. Both (A) and (Z) decreases in `alpha`-decayB. Both (A) and (Z) do not change in `gamma`-decayC. (A) does not change but (Z) decreases by one unitun positrondecay or k-electron captureD. Both (A) and (Z) increases in `beta`-decay |
| Answer» Correct Answer - 4 | |
| 386. |
Consider following figure `A` and `B` indicating distribution of charge density `("electron probability" Psi^(2))` with distance `r`. Select the correct statement:A. `A` and `B` both for `1s`B. `A` and `B` both are for `2s`C. `A` is for `2s`, `B` is for `1s`D. `A` is for `1s`, `B` is for `2s` |
| Answer» Correct Answer - D | |
| 387. |
A photon of frequency `v` causes photo electric emission from a surface with threshold frequency `v_(0)`. The de-Broglies wavelength `(lambda)` of the photo electron emitted is given by:A. `Deltan=(h)/(2mlambda)`B. `Deltan=(h)/(lambda)`C. `[1/v_(0)-1/v]=(mc^(2))/(h)`D. `lambda=sqrt(h/(2mDeltaV))` |
| Answer» Correct Answer - D | |
| 388. |
`3p_(y)` orbital has ……… nodal plane:A. `XY`B. `YZ`C. `ZX`D. All of these |
| Answer» Correct Answer - C | |
| 389. |
`…………………………..` brings fission in `U^(235)`. |
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Answer» Correct Answer - Slow neutrons |
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| 390. |
The reaction `._(13)Al^(27) + ._(2)He^(4) rarr ._(14)Si^(30) + ._(1)H^(1)` is of the typeA. Nuclear fusionB. Nuclear fissionC. Chemical reactionD. Transmutation |
| Answer» Correct Answer - D | |
| 391. |
`._(7)N^(14)+ ._(0)n^(1)rarr ...................+._(1)H^(1)` |
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Answer» Correct Answer - `._(6)C^(14)` |
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| 392. |
If a radioactive element is placed in an evacuated container, its rate of disintegrationA. Will be increasedB. Will be decreasedC. Will change very slightlyD. Will remain unchanged |
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Answer» Correct Answer - D The rate of disintegration does not depend upon environmental factors. |
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| 393. |
Complete the following `:` i.` ._(7)N^(14)+._(2)He^(4)rarr ._(8)O^(17)+……….` `ii. ` `._(92)U^(235)+._(0)n^(1) rarr ._(55)A^(142)+._(37)B^(92)+……….` `iii.` `._(29)Cu^(53)rarr ._(28)Ni^(53)+………………` `iv.` `2 ._(1)H^(3)rarr._(2)He^(4)+.....` `v.` `._(96)Cm^(246)+._(6)C^(12)rarr ._(102)No^(254)+...........` `vi.` `._(94)Pu^(239)+.......rarr._(96)Cm^(242)+._(0)n^(1)` `vii. ` `._(34)Se^(82)rarr ............ +2 ._(-1)e^(0)` |
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Answer» `i.` `._(7)N^(14)+._(2)He^(4)rarr ._(8)O^(17)`+........ or `._(7)N^(14)+._(2)He^(4)rarr._(8)O^(17)+._(Z)X^(m)` Equating mass number on both sides `14+4=17+mimpliesm=-1` Equating atomic number on both sides, `7+2=8+ZimpliesZ=-1` `:. X` is `._(1)X^(1) ,i.e., ._(1)H^(1)` . or `._(7)N^(14)+._(2)He^(4) rarr ._(8)O^(17)+._(1)H^(1)` `ii.` `._(92)U^(235)+._(0)n^(1) rarr._(55)A^(142)+._(37)B^(92)+.....` Equation is `._(92)U^(235)+._(0)n^(1)rarr``_(55)Cs^(142)+._(37)Rb_(92)+2._(0)n^(1)` `iii.` `._(29)Cu^(53) rarr`._(28)Ni^(53)+._(Z)X^(m)` Equating atomic number on both sides and mass number on both sides `Z=0 ` `m=0` `:. ` `._(29)Cu^(53) rarr ._(28)Ni^(53)+._(Z)X^(m)` Equating atomic number on both sides and mass number on bot sides `:. 2 ` `._(1)H^(3) rarr._(2)He^(4)+2 ._(0)n^(1)` `v.` Equating atomic number and mass number on both sides `._(96)Cm^(246)=._(6)C^(12)rarr ._(102)No^(254)+4._(0)n^(1)` `vi.` Equating atomic number and mass number on both sides `._(94)Pu^(239)+._(2)He^(4) rarr ._(96)Cm^(242)+._(0)n^(1)` `vii.` Equating atomic number and mass number on both sides. `._(34)Se^(82) rarr ._(36)Kr^(82)+2._(-1)n^(0)` |
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| 394. |
What is `X` in the nuclear reaction `._(7)N^(14) + ._(1)H^(1) rarr ._(8)O^(15) + X`A. `._(1)H^(2)`B. `._(0)n^(1)`C. `gamma`D. `._(-1)e^(0)` |
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Answer» Correct Answer - C `._(7)N^(14) + ._(1)H^(1) rarr ._(8)O^(15) + ._(Z)X^(A)` Equating mass number on both sides `14 + 1 = 15 + A` `:. A = 0` Equating atomic number on the sides `7 + 1 = 8 + Z` `:. Z = 0` The particles is `gamma`. |
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| 395. |
The half-life of a radioactive isotope is 3 hours. Value of its disintegration constant isA. 0.231 per hrB. 2.31 per hrC. 0.2079 per hrD. 2.079 per hr |
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Answer» Correct Answer - A `k = (0.693)/(t_(1//2)) = (0693)/(3hr) = 0.231` per hr. |
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| 396. |
Which of the following projectiles is the best for bombarding the nuclide?A. `alpha`-particleB. ProtonC. DeuteronD. Neutron |
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Answer» Correct Answer - D Neutron is the best projectile. |
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| 397. |
Which of the following nuclear change is incorrect?A. `._(20)Ca^(40) + ._(0)n^(1) rarr ._(19)K^(40) + ._(1)H^(1)`B. `._(12)Mg^(24) + alpha rarr ._(14)Si^(27) + ._(0)n^(1)`C. `._(48)Cd^(113) + ._(0)n^(1) rarr ._(48)Cd^(112) + ._(-1)e^(0)`D. `._(20)Co^(43) + alpha rarr ._(21)Si^(46) + ._(1)H^(1)` |
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Answer» Correct Answer - C In the given reaction, conservation of atomic mass and atomic number is violated. |
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| 398. |
75 atoms of radio active species are decayed in 2 half lives (`t""_(1//2)=1hr`) if 100 atoms are taken initially. Number of atoms decayed if 200 atoms are taken in two hours areA. 75B. 150C. 50D. 200 |
| Answer» Correct Answer - b | |
| 399. |
Percentage of a radioactive element decayed after 20 s when half-life is 4 sA. 92.25B. 96.87C. 50D. 75 |
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Answer» Correct Answer - B `n = (20)/(4) = 5, (N_(t))/(N_(0)) = ((1)/(2))^(5) = (1)/(32), :.` decayed `= (1 -(1)/(32)) xx 100 = (31)/(32) xx 100 = 96.87` |
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| 400. |
Which metal Aprons are worn by radiographer to protect him from radiationA. Mercury coated apronB. Lead apronC. Copper apronD. Aluminimised apron |
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Answer» Correct Answer - B Lead absorb the harmful radiations |
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