94420 + Interview Questions in Chemistry in Class 12 Page 500 InterviewSolution

24951.	The rapiddepletion of fossil fuels has inspiredextensive research in the area of alternative and renewale energy sources. Of these, hydroden is the most Contemplated fuel of the future . Howevercost effective production and hazard free storage are major issuses is using H_(2) (Note : use the data in table-1 given at the end of partA,whenever necessary.) 1kg of hydrogen is burnt with oxgyen at 25^(@)C and the heat energy is used for different purpose . Using this heat calculate (i) the maximum theoretical work. (ii) work that can be produced by a heat engine working between 25^(@)Cto 300^(@) C. (The efficiency of a heat engine =work done /heat absorbed =[1-9T_("low")//T_("high")] where T is in K)
Answer» SOLUTION :N//A

Discussion

24952.	The rapiddepletion of fossil fuels has inspiredextensive research in the area of alternative and renewale energy sources. Of these, hydroden is the most Contemplated fuel of the future . Howevercost effective production and hazard free storage are major issuses is using H_(2) (Note : use the data in table-1 given at the end of partA,whenever necessary.) Assuming complete combustion, calculate heat of combustion when (i)1 g of hydrogen and (ii) 1 g of carbon are burnt.
Answer» SOLUTION :N//A

Discussion

24953.	The rapiddepletion of fossil fuels has inspiredextensive research in the area of alternative and renewale energy sources. Of these, hydroden is the most Contemplated fuel of the future . Howevercost effective production and hazard free storage are major issuses is using H_(2) (Note : use the data in table-1 given at the end of partA,whenever necessary.) A cylinder contains hydrogen at a pressure of 80Moa at 25^(@)C , Assuming ideal behaviour , Calculate the density of hydrogen in the cylinder in Kg//m^(3) .
Answer» SOLUTION :N//A

Discussion

24954.	The rapid change of pH near the stoichiometric point of an acid-base titration is the basis of indicator detection. The pH of the solution is related to ratio of the concentration of the conjugate acid (Hin) and base (In^(-)) forms of the indicator by the expression
Answer» `"log"([In^(-)])/([HIN])=pK_(In)-PH` `"log"([HIn])/([In])=pK_(In)-pH` `"log"([HIn])/([In^(-)])=pH-pK_(In)` `"log"([In^(-)])/([HIn])=pH-pK_(In)` ANSWER :B

Discussion

24955.	The rapid change of pH near the stoichiometricpoint of an acid-base titration is the basis of indicator detection. pH of the solution is related to ratio of the concentration of the conjugate acid (Hin) and base [H^(+)] = 10^(-7) + 10^(-8) = 10^(-7)[1+0.1] forms of the indicator by the expression
Answer» `LOG.([HIn])/([In^(-)]) = PH - pK_(In)` `log.([In^(-)])/([HIn]) = pH - pK_(In)` `log.([In^(-)])/([HIn]) = pK_(In) - pH` `log.([HIn])/([In^(-)]) = pK_(In) - pH` Answer :B

Discussion

24956.	The rank of a cubic unit cell is 4. The type of cell as- (A) Body centred (B) Face centred (C) Primitive (D) None
Answer» Solution : (B) The NUMBER of atoms PRESENT in sc, fcc and BCC unit CELL are 1, 4, 2 respectively.

Discussion

24957.	The range of radius ratio (cationic to anionic) for an octahedral arrangement of ions in an ionic solid is
Answer» `0-0.155` `0.155-0.225` `0.255-0.414` `0.414-0.732` SOLUTION :For OCTAHEDRAL ` R^(+)//r^(-)=0.414-0.732`.

Discussion

24958.	The rank of a cubic unit cell is 4. The type of cell as:
Answer» BODY centred Face centred Primitive None Answer :B

Discussion

24959.	The rank (effective atoms per unit cell) of a cubic unit cell is 4. The type of cell as-
Answer» Body centred FACE centred PRIMITIVE NONE of these Answer :B

Discussion

24960.	The range of phin which methyl orange works as indicator:
Answer» 3-4 10-12 8-10 6-8 Answer :A

Discussion

24961.	The range of microbes attackedby antibiotics is known as
Answer» spectrum bands bactiria all of these ANSWER :A

Discussion

24962.	The radius of ""_(Z) M^(A) nucleus is (outer most configuration 3s^(2) 3p^(1) and A + Z = 40)
Answer» 4.2 FM `1.4 XX root340 FM` `1.4 xx ROOT2 40 FM` `1.4 xx 40` F M Solution :`r = r_0 (A^(1//3)) 1.4 xx (27)^(1//3) = 1.4 xx 3 = 4.2`

Discussion

24963.	The random, zig-zag motion of colloidal particles in the dispersion medium is referred to Electrophoresis as.....
Answer» ELECTROPHORESIS Brownian movement TYNDALL effect ELECTRO OSMOSIS SOLUTION : Brownian movement

Discussion

24964.	The radius ratio of the cation to the anion of an ionic compound is 0.4. Its structural arrangement is
Answer» PLANAR TRIANGULAR Tetrahedral Octahedral Body-centred cubic Solution :As radius RATIO lies inthe range `0.225-0.414`,C . N . = 4 and arrangement is tetrahedral .

Discussion

24965.	The range of methyl orange as an indicator is in between pH
Answer» `6-8` `8-9` `3-5` `2-4` SOLUTION :As METHYL ORANGE is a WEAK BASE.

Discussion

24966.	The radius r of an atom in a body-centred cubic is given by
Answer» `r=(SQRT(3))/(2)a` `r=(4)/sqrt(3a)` `r=(sqrt(3))/(4)a` `r=(4A)/sqrt(3)` Answer :C

Discussion

24967.	the radius of which of the following orbit is same as that of the first Bohr's orbit of hydrogen atom?
Answer» `Be^(3+) (n=2)` `He^(2+) (n=2)` `Li^2+ (n=2)` `Li^2+ (n=3)` ANSWER :A

Discussion

24968.	The radius of water molecule having density 1g mL^(-1) is:
Answer» 1.925 `OVERSET(@)A` 73.46 `overset(@)A` 19.25 `overset(@)A` 7.346 `overset(@)A` ANSWER :A

Discussion

24969.	The radius of the second Bohr orbit for hydrogen atom is (Planck's constant (h) - 6.6262 xx 10^(-34)Js, mass of electron = 9.1091 xx 10^(-31) kg, charge of electron (e) = 1.60210 xx 10^(-19)C, permitivity of vacuum (in_(0)) = 8.854185 xx 10^(-12) kg^(-1) m^(-3) A^(2))
Answer» `1.65 Å` `4.76 Å` `0.529 Å` `2.12 Å` ANSWER :C

Discussion

24970.	The radius of the largest sphere which fits properly at the centre of the edge of the bodycentred cubic unit cell is ………….. (Edge length is represented by "a")
Answer» 0.134 a 0.027 a 0.067 a 0.047 a Solution :For a body centred unit CELL : `sqrt(3)a = 4R`...(i) EDGE length `(a)= 2(R + r)` `a/2 = R + r` .. (II) On SOLVING (i) and (ii) `r = ((2 - sqrt(3))/(4)) a` ` implies` r = 0.067 a

Discussion

24971.	The radius of Na^+ is 95 pm and Cl^- ion 181 pm. Find co-ordination number of Na^+ ion.
Answer» 4 6 8 Unpredictable Answer :B

Discussion

24972.	The radius of the first Bohr orbit of hydrogen atom is r. The radius of the 3rd orbit would be
Answer» 3r 9r 27r none of these Answer :B

Discussion

24973.	The radius of second Bohr orbit for hydrogen atom is (h= 6.6262 xx 10^(-34)Js, mass of electron =9.1091 xx 10^(-31)kg, charge e= 1.60210 xx 10^(-19)C, permitivity of vacuum, in_(0)= 8.854185 xx 10^(-12)kg^(-1) m^(-3) A^(2))
Answer» `1.65 Å` `4.76 Å` `0.529 Å` `2.12 Å` Solution :`r= (in_(0)n^(2)H^(2))/(pi m E^(2)z), 1 Å= 10^(-10)m`

Discussion

24974.	The radius of Na^(+) ion is 95 pm and that of Cl^(-) ion is 181 pm. Predict the structure of Na^(+)Cl^(-) and the coordination number of cation.
Answer» Solution :`(r_(Na^(+)))/(r_(CL^(-)))=(95)/(181)= 0.524` Since the RADIUS ratio lies between 0.414-0.732, the structure will be OCTAHEDRAL with coordination NUMBER 6.

Discussion

24975.	The radius of Li^(+) ion is 60 pm and that of F^(-) is 136 pm. Structure of LiF and coordination number is
Answer» LIKE NaCl, C.No.=6 Like CsCl,C. No=8 Anti fluoride, C. No=8 None of these Solution :`(R^(+))/(r^(-))` ratio is `(60)/(13.6)=0.441`. HENCE LiF has NaCl STRUCTURE with C.N.=6

Discussion

24976.	The radius of La^(3-) (at. No. 57) is 1.06 Å, Which one of the following given values will be closest to the radius of Lu^(3-) (at. No. 71)?
Answer» 1.60 A 1.40 A 1.06 A 0.85 A Solution :SINCE ionic RADII of lanthanoids decrease along the SERIES then ionic radii of `Lu^(3+)(Z=71)` must be much SAMMER than that of `La^(3+)` (atomic NUMBER 57). Hence ionic radii of `Lu^(3+)` should be close to `0.85Å`.

Discussion

24977.	The radius of La^(3+) (At No. of La = 57) is 1.06Å. Which one of the following given value will be closest to the radius fo Lu^(3+) (Atomcic NO. ofLu = 71) ?
Answer» `140Å` `106Å` `085Å` `160Å` Solution :Due to lanthanoid contraction, the ionic RADII of LANTHANOIDS decreases from `La^(3+)` to `LU^(3+)`. Therefore, the lowest value (0.85 Å) is the ionic radius of `Lu^(3+)`

Discussion

24978.	The radius of Bohr's first orbit in H atom is 0.053 nm. The radius of second orbit in He^+ would be:
Answer» 0.0265 nm 0.0530 nm 0.1060 nm 0.2120 nm Answer :C

Discussion

24979.	The radius of atom is 300 pm. If it crystallizes in a face-centred cubic lattice, calculate the distance between nearest neighbour.
Answer» ANSWER :600 PM

Discussion

24980.	The radius of an ion in a body-centred cube of edge a is:
Answer» `a/2` `(SQRT(2)a)/4` `(sqrt(3)a)/4` NONE ofthese Answer :C

Discussion

24981.	The radius of an atom is 300pm, if it crystallizes in a face centered cubic lattice, the length of the edge of the unit cell is …………….. .
Answer» 488,5 on 848,5 on 884,5 on 484.5 on Solution :Hint : `"Let EDGE LENGTH"=asqrt2a=4r` `a=(4xx300)/(SQRT2)` `a=600xx1.414""a=848.4" PM"`

Discussion

24982.	The radius of a hydrogen atom is 5.32 xx10^(-11) mand the radius of a proton at the centre is 1.5 xx 10^(-5)m. The ratio of the radius of the atom to the radius of proton is :
Answer» `3.5 xx 10^(-6)` `3.54 xx 10^(-6)` `3.55 xx 10^(-6)` `4 xx 10^(-6)` Solution :`("RADIUS of atom")/(Radius of proton")= (5.32 xx 10^(-11))/(1.5 xx 10^(-5) )` ` = 3.5 xx 10^(-6) ` ANSWER is reported UPTO 2 significant figures as in 1.5

Discussion

24983.	The radius of Ag^+ ion is 126 pm while that of I^- ion is 216 pm . The coordination number of Ag in Agl is :
Answer» 2 4 6 8 Answer :C

Discussion

24984.	The radius of A^(+) is 0.95 Å andof B^(-) is 1.81 Å. The coordination number of A^(+) is :
Answer» 4 6 8 2 Solution :`( r_(A^(+)))/( r_(B^(-))) = ( 0.95)/( 1.81 ) = 0.523` SINCE RADIUS ratio `( r^(+) // r^(-))`lies between 0.414 - 0.732 , the coordination NUMBER is 6.

Discussion

24985.	The radioisotpe, tritum (._(1)^(3)H) has a half-life of 12.3 years. If the initial amount of tritium is 32 mg, how many milligrams of it would remain after 49.2 years
Answer» 8 mg 1 mg 2 mg 4 mg Solution :`N_(t) = N_(0) ((1)/(2))^(n) = 32 xx ((1)/(2))^(49.2//12.3)= 32 xx ((1)/(2))^(4) = 2`

Discussion

24986.	The radius of a calcium ion is 94 pm and of the oxide ion is 146 pm. The possible crystal structure of calcium oxide will be
Answer» tetrahedral trigonal octahedral pyramidal Solution :As per formula, radius ratio`=("radius of cation")/("radius of anion")` `=(94)/(146)=0.643` Since the value is between 0.414 - 0. 732 hence thecoordination no. will be 6 and GEOMETRY will beoctahedral

Discussion

24987.	The radium and uranium atoms in a sample of uranium mineral are in the ratio of 1 : 2.8 xx 10^(6). If half-life period of radium is 1620 years, the half-life period of uranium will be
Answer» `45.3 XX 10^(9)` years `45.3 xx 10^(10)` years `4.53 xx 10^(9)` years `4.53 xx 10^(6)` years Solution :According to radioactive equilibrium `lamda_(A) N_(A) = lamda_(B) N_(B)` or `(0.693 xx N_(A))/(t_(1//2) (A)) = (0.693 xx N_(B))/(t_(1//2) (B)) [LAMDA = (0.693)/(t_(1//2))]` Where `t_(1//2) (A) and t_(1//2) (B)` are half periods of A and B RESPECTIVELY `:. (N_(A))/(t_(1//2)(A)) = (N_(B))/(t_(1//2)(B)) or (N_(A))/(N_(B)) = (t_(1//2) (A))/(t_(1//2)(B))` `:.` At equilibrium Aand B are present in the ratio of their half lives `(1)/(2.8 xx 10^(6)) = (1620)/("Half-life of uranium")` `:.` Half-life of uranium `2.8 xx 10^(6) xx 1620 = 4.53 xx 10^(9)` years

Discussion

24988.	The radioisotope, tritium (""_(1)^(3)H) has a half-life of 12.3 years. If the initial amount of tritium is 32 mg. how many milligrams of it would remain after 49.2 years?
Answer» 1 mg 2 mg 4 mg 8 mg SOLUTION :NUMBER of half - lives in 49.2 years = 4 `32 mg to 16 mg to 8 mg to 4 mg to 2 mg`.

Discussion

24989.	The radioaisotope of hydrogen has a half-life of 12.33 y. What is the age of an old bottle of wine whose ._(1)^(3)H radiation is 10% of that present in a new bottle of wine
Answer» 41y 12.3 y 1.233 y 410 y Answer :A

Discussion

24990.	The radioisotope ""_(15)^(32)P is used in biochemical studies. A sample containing this isotope has an activity 1000 times the detectable limit. How long could an experiment be run with the sample before the radioactivity could no longer be detected ? Half-life of ""_(15)^(32)P is 14.2 days
Answer» <P> Solution :The minimum NUMBER of P atoms, the radioactivity of which could be detected, is one, and so the sample will initially contain 1000 atoms of P. Thus, `(N^(0))/(N) = (1000)/(1)` Now, `lamda= (2.303)/(t) "log" (N^(0))/(N)` `(0.6932)/(14.2) = (2.303)/(t) "log" (1000)/(1)` or t=141.5 DAYS

Discussion

24991.	The radioactivity of uranium mineras is usually more in comparison to pure uranium. This is due to presence of … in the mineral.
Answer» actinium thorium radium plutonium Answer :C

Discussion

24992.	The radioactively due to C^(14) isotope (half-life 6000 years) of a sample of wood from an ancient tomb was found to be nearly half that of fresh wood, the tomb is therefore about
Answer» 3000 years old 6000 years old 9000 years old 1200 years old Solution :`N = N_(0) xx ((1)/(2))^(n)` `(1)/(2) = 1 xx ((1)/(2))^(n) , n = 1` `t = n xxt_(1//2) = 1 xx 6000 = 6000` yrs

Discussion

24993.	The radioactivity due to C-14 isotope (half-life = 6000 years) of a sample of wood form an ancient tomb was found to be nearly half that of fresh wood. The bomb is there for about how many years old?a)3000b)6000c)9000d)12000
Answer» 3000 YEARS old 6000 years old 9000 years old 12000 years old Answer :B

Discussion

24994.	The radioactive series whose end product is ._(83)^(209)Bi is
Answer» Thorium series Fourier series Actinium series Neptunium series Solution :`._(83)^(209)BI` is the END product of Neptunium series i.e., `4N +1` (ARTIFICIAL) series

Discussion

24995.	The radioactive sources A and B of half lives of t hr and 2t hr respectively, initially contain the same number of radioactive atoms. At the end of t hours, their rates of disintegration are in the ratio:
Answer» `2sqrt(2) :1` `1 : 8` `sqrt(2) : 1` ln `2 : 1` Solution :`{:(,A=(t_(1//2)=t"HOUR")/(lambda_(1))X "",, B=(t_(t//2)=2t"hour")/(lambda_(2)),),("at " t=0,,,,),("No. of nuclei",""N_(0),,""N_(0),),(,"Nuclei of A left after time "t(t=t_(1//2)),,"Nuclei of B left after time "t,),(,=(N_(0))/(2),,=N_(0)e^(-lambda_(2)t),),(,"Rate of disintegration of A",,=N_(0)e^(-(LN2)/(2 t)t),),(,=lambda_(1)(N_(0))/(2),,=N_(0)e^(ln((1)/(2))^(1//2)),),(,=(ln 2)/(t) (N_(0))/(2),,=(N_(0))/(sqrt(2)),),(,,,"Rate of disintegration of B",),(,,,=lambda_(2)(N_(0))/(sqrt(2))=(ln2)/(2t)(N_(0))/(sqrt(2)),):}` Ratio of rate of disintegration of A &B `=((ln2)/(t)(N_(0))/(2))/((ln2)/(2t)(N_(0))/(sqrt(2)))=(sqrt(2))/(1)`

Discussion

24996.	The radioactive isotope of carbon used in radio carbon dating is :
Answer» `""_(6)^(12)C` `""_(6)^(13)C` `""_(6)^(14)C` `""_(6)^(16)C` Answer :C

Discussion

24997.	The radioactive nucleide ""_(90)^(134)Th undergoes two successive beta- deacys followed by one alpha- decay. The atomic number and mass number respectively of the resulting radionucleide is :
Answer» 94 and 230 90 and 230 92 and 230 92 and 234 Solution :`""_(92)^(234)Thoverset(2-overset(0)1E)to""_(92)^(234)Xoverset(-_(2)^(4)He)to""_(90)^(230)Y`

Discussion

24998.	The radioactive isotope ._(27)^(60)Co which is used in the treatment of cancer can be made by (n,p) reaction. For this reaction the target nucleus is
Answer» `._(28)^(60)NI` `._(27)^(60)CO` `._(28)^(59)Ni` `._(27)^(59)Co` Solution :`._(28)Ni^(6) + ._(0)n^(1) RARR ._(28)Ni^(61) rarr ._(27)Co^(60) + ._(1)p^(1)`

Discussion

24999.	The radioactive decay of ._(35)X^(88) by a beta emission produces an unstable nucleus which spontaneously emits a neutron. The final product is
Answer» `.(37)X^(88)` `._(35)Y^(89)` `._(34)Z^(88)` `._(36)W^(87)` Solution :`._(35)X^(88) overset(-BETA)RARR ._(36)W^(88) rarr ._(36)W^(87) + ._(0)n^(1)`

Discussion

25000.	The radioactive decay rate of a radioactive element is found to be 10^(3) dps at a certain time . If the half life of element is 1 sec , the decay rate after 1 sec , is ….and after 3 sec , is …….
Answer» 500 , 125 125500 `10^(3) , 10^(3)` `100 , 10` Solution :`1000 dps overset( 1" SEC")(to) 500 overset("1SEC")(to) 250 overset("1 sec") (to) 125`

Discussion

Explore topic-wise InterviewSolutions in .

The rapid change of pH near the stoichiometric point of an acid-base titration is the basis of indicator detection. The pH of the solution is related to ratio of the concentration of the conjugate acid (Hin) and base (In^(-)) forms of the indicator by the expression

The rapid change of pH near the stoichiometricpoint of an acid-base titration is the basis of indicator detection. pH of the solution is related to ratio of the concentration of the conjugate acid (Hin) and base [H^(+)] = 10^(-7) + 10^(-8) = 10^(-7)[1+0.1] forms of the indicator by the expression

The rank of a cubic unit cell is 4. The type of cell as- (A) Body centred (B) Face centred (C) Primitive (D) None

The range of radius ratio (cationic to anionic) for an octahedral arrangement of ions in an ionic solid is

The rank of a cubic unit cell is 4. The type of cell as:

The rank (effective atoms per unit cell) of a cubic unit cell is 4. The type of cell as-

The range of phin which methyl orange works as indicator:

The range of microbes attackedby antibiotics is known as

The radius of ""_(Z) M^(A) nucleus is (outer most configuration 3s^(2) 3p^(1) and A + Z = 40)

The random, zig-zag motion of colloidal particles in the dispersion medium is referred to Electrophoresis as.....

The radius ratio of the cation to the anion of an ionic compound is 0.4. Its structural arrangement is

The range of methyl orange as an indicator is in between pH

The radius r of an atom in a body-centred cubic is given by

the radius of which of the following orbit is same as that of the first Bohr's orbit of hydrogen atom?

The radius of water molecule having density 1g mL^(-1) is:

The radius of the second Bohr orbit for hydrogen atom is (Planck's constant (h) - 6.6262 xx 10^(-34)Js, mass of electron = 9.1091 xx 10^(-31) kg, charge of electron (e) = 1.60210 xx 10^(-19)C, permitivity of vacuum (in_(0)) = 8.854185 xx 10^(-12) kg^(-1) m^(-3) A^(2))

The radius of the largest sphere which fits properly at the centre of the edge of the bodycentred cubic unit cell is ………….. (Edge length is represented by "a")

The radius of Na^+ is 95 pm and Cl^- ion 181 pm. Find co-ordination number of Na^+ ion.

The radius of the first Bohr orbit of hydrogen atom is r. The radius of the 3rd orbit would be

The radius of second Bohr orbit for hydrogen atom is (h= 6.6262 xx 10^(-34)Js, mass of electron =9.1091 xx 10^(-31)kg, charge e= 1.60210 xx 10^(-19)C, permitivity of vacuum, in_(0)= 8.854185 xx 10^(-12)kg^(-1) m^(-3) A^(2))

The radius of Na^(+) ion is 95 pm and that of Cl^(-) ion is 181 pm. Predict the structure of Na^(+)Cl^(-) and the coordination number of cation.

The radius of Li^(+) ion is 60 pm and that of F^(-) is 136 pm. Structure of LiF and coordination number is

The radius of La^(3-) (at. No. 57) is 1.06 Å, Which one of the following given values will be closest to the radius of Lu^(3-) (at. No. 71)?

The radius of La^(3+) (At No. of La = 57) is 1.06Å. Which one of the following given value will be closest to the radius fo Lu^(3+) (Atomcic NO. ofLu = 71) ?

The radius of Bohr's first orbit in H atom is 0.053 nm. The radius of second orbit in He^+ would be:

The radius of atom is 300 pm. If it crystallizes in a face-centred cubic lattice, calculate the distance between nearest neighbour.

The radius of an ion in a body-centred cube of edge a is:

The radius of an atom is 300pm, if it crystallizes in a face centered cubic lattice, the length of the edge of the unit cell is …………….. .

The radius of a hydrogen atom is 5.32 xx10^(-11) mand the radius of a proton at the centre is 1.5 xx 10^(-5)m. The ratio of the radius of the atom to the radius of proton is :

The radius of Ag^+ ion is 126 pm while that of I^- ion is 216 pm . The coordination number of Ag in Agl is :

The radius of A^(+) is 0.95 Å andof B^(-) is 1.81 Å. The coordination number of A^(+) is :

The radioisotpe, tritum (._(1)^(3)H) has a half-life of 12.3 years. If the initial amount of tritium is 32 mg, how many milligrams of it would remain after 49.2 years

The radius of a calcium ion is 94 pm and of the oxide ion is 146 pm. The possible crystal structure of calcium oxide will be

The radium and uranium atoms in a sample of uranium mineral are in the ratio of 1 : 2.8 xx 10^(6). If half-life period of radium is 1620 years, the half-life period of uranium will be

The radioisotope, tritium (""_(1)^(3)H) has a half-life of 12.3 years. If the initial amount of tritium is 32 mg. how many milligrams of it would remain after 49.2 years?

The radioaisotope of hydrogen has a half-life of 12.33 y. What is the age of an old bottle of wine whose ._(1)^(3)H radiation is 10% of that present in a new bottle of wine

The radioisotope ""_(15)^(32)P is used in biochemical studies. A sample containing this isotope has an activity 1000 times the detectable limit. How long could an experiment be run with the sample before the radioactivity could no longer be detected ? Half-life of ""_(15)^(32)P is 14.2 days

The radioactivity of uranium mineras is usually more in comparison to pure uranium. This is due to presence of … in the mineral.

The radioactively due to C^(14) isotope (half-life 6000 years) of a sample of wood from an ancient tomb was found to be nearly half that of fresh wood, the tomb is therefore about

The radioactivity due to C-14 isotope (half-life = 6000 years) of a sample of wood form an ancient tomb was found to be nearly half that of fresh wood. The bomb is there for about how many years old?a)3000b)6000c)9000d)12000

The radioactive series whose end product is ._(83)^(209)Bi is

The radioactive sources A and B of half lives of t hr and 2t hr respectively, initially contain the same number of radioactive atoms. At the end of t hours, their rates of disintegration are in the ratio:

The radioactive isotope of carbon used in radio carbon dating is :

The radioactive nucleide ""_(90)^(134)Th undergoes two successive beta- deacys followed by one alpha- decay. The atomic number and mass number respectively of the resulting radionucleide is :

The radioactive isotope ._(27)^(60)Co which is used in the treatment of cancer can be made by (n,p) reaction. For this reaction the target nucleus is

The radioactive decay of ._(35)X^(88) by a beta emission produces an unstable nucleus which spontaneously emits a neutron. The final product is

The radioactive decay rate of a radioactive element is found to be 10^(3) dps at a certain time . If the half life of element is 1 sec , the decay rate after 1 sec , is ….and after 3 sec , is …….