# Nuclear Chemistry Test 4

Total Questions:50 Total Time: 75 Min

Remaining:

## Questions 1 of 50

Question:Heavy water freezes at

$${0^0}C$$

$${3.8^0}C$$

$${38^0}C$$

$$- {0.38^0}C$$

## Questions 2 of 50

Question:To determine the masses of the isotopes of an element which of the following techniques is useful

The acceleration of charged atoms by an electric field and their subsequent deflection by a variable magnetic field

The spectroscopic examination of the light emitted by vaporised

elements subjected to electric discharge

The photographing of the diffraction patterns which arise when X-rays are passed through crystals

The bombardment of metal foil with alpha particles

## Questions 3 of 50

Question:The radioisotope, tritium $$(_1^3H)$$ 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

8 mg

1 mg

2 mg

4 mg

## Questions 4 of 50

Question:When a radioactive substance is subjected to vacuum, the rate of disintegration per second

Increases considerably

Increases only if the products are gaseous

Is not affected

Suffers a slight decrease

## Questions 5 of 50

Question:A radio isotope will not emit

Gamma and alpha rays simultaneously

Gamma rays only

Alpha and beta rays simultaneously

Beta and gamma rays simultaneously

## Questions 6 of 50

Question:$${D_2}O$$ is used in

Industry

Nuclear reactor

Medicine

Insecticide

## Questions 7 of 50

Question:India conducted an underground nuclear test at

Tarapur

Narora

Pokhran

Pushkar

## Questions 8 of 50

$$Tim{e^{{\rm{-1}}}}$$

Time

$$Mole-tim{e^{-1}}$$

$$Time-mol{e^{-1}}$$

## Questions 9 of 50

Question:Which of the following is used in dating archeological findings or In a method of absolute dating of fossils a radioactive element is used. It is

$$_{92}{U^{235}}$$

$$_6{C^{14}}$$

$$_6{C^{12}}$$

$$_{20}C{a^{40}}$$

## Questions 10 of 50

Question:The radioactivity 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

$$_{28}^{60}Ni$$

$$_{27}^{60}Co$$

$$_{28}^{59}Ni$$

$$_{27}^{59}Co$$

## Questions 11 of 50

Question:Fusion bomb involves

Combination of lighter nuclei into bigger nucleus

Destruction of heavy nucleus into smaller nuclei

Combustion of oxygen

Explosion of TNT

## Questions 12 of 50

Question:The number of neutrons in the parent nucleus which gives $${N^{14}}$$ on $$\beta$$-emission and the parent nucleus is

$$8,\,{C^{14}}$$

$$6,\,{C^{12}}$$

$$4,\,{C^{13}}$$

None of these

## Questions 13 of 50

Question:After the emission of $$\alpha$$-particle from the atom $$_{92}{X^{238}}$$, the number of neutrons in the atom will be

138

140

144

150

## Questions 14 of 50

Question:A nuclide of an alkaline earth metal undergoes radioactive decay by emission of the $$\alpha-$$particles in succession. The group of the periodic table to which the resulting daughter element would belong is

Gr.14

Gr.16

Gr.4

Gr.6

## Questions 15 of 50

Question:Which one of the following is not correct

$$_3L{i^7}+{\,_1}{H^1}\to{\,_4}B{e^7}+{\,_0}{n^1}$$

$$_{21}S{c^{45}}+{\,_0}{n^1}\to{\,_{20}}C{a^{45}}+{\,_0}{n^1}$$

$$_{33}A{s^{75}}+{\,_2}H{e^4}\to{\,_{35}}B{r^{78}}+{\,_0}{n^1}$$

$$_{83}B{i^{209}}+{\,_1}{H^2}\to{\,_{84}}P{o^{210}}+{\,_0}{n^1}$$

## Questions 16 of 50

Question:Atomic number after a $$\beta$$-emission from a nucleus having atomic number 40, will be

36

39

41

44

## Questions 17 of 50

Question:A certain nuclide has a half-life period of 30 minutes. If a sample containing 600 atoms is allowed to decay for 90 minutes, how many atoms will remain

200 atoms

450 atoms

75 atoms

500 atoms

## Questions 18 of 50

Question:If half-life of a certain radioactive nucleus is $$1000\,s,$$ the disintegration constant is

$$6.93\times{10^2}{s^{-1}}$$

$$6.93\times{10^{-4}}s$$

$$6.93\times{10^{-4}}{s^{-1}}$$

$$6.93\times{10^3}s$$

## Questions 19 of 50

Question:Radioactivity of naptunium stops when it is converted to

Bi

Rn

Th

Pb

## Questions 20 of 50

Question:Substances which have identical chemical properties but differ in atomic weights are called

Isothermals

Isotopes

Isentropus

Elementary particles

## Questions 21 of 50

Question:Tritium is an isotope of

Hydrogen

Titanium

Tantalum

Tellurium

## Questions 22 of 50

Question:An isotope of ‘parent’ is produced, when its nucleus loses

One $$\alpha$$-particle

One $$\beta$$-particle

One $$\alpha$$ and two $$\beta$$-particles

One $$\beta$$ and two $$\alpha$$- particles

## Questions 23 of 50

Question:Which of the following isotopes is likely to be most stable

$$_{30}Z{n^{71}}$$

$$_{30}Z{n^{66}}$$

$$_{30}Z{n^{64}}$$

None of these

## Questions 24 of 50

Question:Addition of two neutrons in an atom $$A$$ would

Change the chemical nature of $$A$$

Produce an isobar of $$A$$

Produce an isotope of A

Produce another element

## Questions 25 of 50

Question:Atomic weight of the isotope of hydrogen which contains 2 neutrons is the nucleus would be

2

3

1

4

## Questions 26 of 50

Question:In chlorine gas, ratio of $$C{l^{35}}$$ and $$C{l^{37}}$$is

1/3

3/1

1/1

1/4

## Questions 27 of 50

Question:An ordinary oxygen contains

Only $$O-16$$ isotopes

Only $$O-17$$ isotopes

A mixture of $$O-16$$ and $$O-18$$ isotopes

A mixture of O – 16, $$O-17$$ and $$O-18$$ isotopes

## Questions 28 of 50

Question:Which can be used for carrying out nuclear reaction

Uranium – 238

Neptunium – 239

Thorium – 232

Plutonium – 239

## Questions 29 of 50

Question:On comparing chemical reactivity of $${C^{12}}$$ and $${C^{14}}$$, it is revealed that

$${C^{12}}$$ is more reactive

$${C^{14}}$$ is more reactive

Both are inactive

Both are equally active

## Questions 30 of 50

Question:In the reaction $$_{93}N{p^{239}}{\to_{94}}P{u^{239}}$$ + (?), the missing particle is

Proton

Positron

Electron

Neutron

## Questions 31 of 50

Question:According to the nuclear reaction $$_4Be{+_2}H{e^4}{\to_6}{C^{12}}{+_0}n{^1}$$, mass number of $$(Be)$$ atom is

4

9

7

6

## Questions 32 of 50

Question:A particle having the same charge and 200 times greater mass than that of electron is

Positron

Proton

Neutrino

Meson

## Questions 33 of 50

Question:The positron is

$$_{-1}{e^0}$$

$$_{+1}{e^0}$$

$$_1{H^1}$$

$$_0{n^1}$$

## Questions 34 of 50

Question:Nuclear reactivity of Na and $$N{a^+}$$ is same because both have

Same electron and proton

Same proton and same neutron

Different electron and proton

Different proton and neutron

## Questions 35 of 50

Question:Which of the following is the heaviest metal

Hg

Pb

Ra

U

## Questions 36 of 50

Question:Alpha rays consist of a stream of

$${H^+}$$

$$H{e^{+2}}$$

Only electrons

Only neutrons

## Questions 37 of 50

Question:Which is the correct statement

$$\beta$$-rays are always negatively charged particles

$$\alpha$$-rays are always negatively charged particles

$$\gamma$$-rays can be deflected in magnetic field

## Questions 38 of 50

Question:There exists on $$\gamma$$-rays

Positive charge

Negative charge

No charge

Sometimes positive charge, sometimes negative charge

## Questions 39 of 50

Question:Which is not emitted by radioactive substance

$$\alpha$$-rays

$$\beta$$-rays

Positron

Proton

## Questions 40 of 50

Question:The atomic mass of an element is 12.00710 amu. If there are 6 neutrons in the nucleus of the atom of the element, the binding energy per nucleon of the nucleus will be

7.64 MeV

76.4 MeV

764 MeV

0.764 MeV

## Questions 41 of 50

Question:Half-life period of a metal is 20 days. What fraction of metal does remain after 80 days

1

1/16

1/4

1/8

## Questions 42 of 50

Question:During a negative $$\beta$$-decay

An atomic electron is ejected

An electron which is already present within the nucleus is ejected

A neutron in the nucleus decays emitting an electron

A part of the binding energy of the nucleus is converted into an electron

## Questions 43 of 50

Question:The decay constant of a radioactive sample is $$'\lambda'$$. The half-life and mean life of the sample are respectively

$$\frac{1}{\lambda},\,\frac{{\ln\,2}}{\lambda}$$

$$\frac{{\ln\,2}}{\lambda},\,\frac{1}{\lambda}$$

$$\lambda\,\ln\,2,\,\frac{1}{\lambda}$$

$$\frac{\lambda}{{\ln\,2}},\,\frac{1}{\lambda}$$

## Questions 44 of 50

Question:Half-life of $$10gm$$ of radioactive substance is 10 days. The half-life of $$20gm$$ is

10 days

20 days

25 days

Infinite

## Questions 45 of 50

Question:$$8gm$$ of the radioactive isotope, cesium-137 were collected on February 1 and kept in a sealed tube. On July 1, it was found that only $$0.25gm$$ of it remained. So the half-life period of the isotope is

37.5 days

30 days

25 days

50 days

## Questions 46 of 50

Question:The half-life of $$_{92}{U^{238}}$$ is $$4.5\times{10^9}$$ years. After how many years, the amount of $$_{92}{U^{238}}$$ will be reduced to half of its present amount

$$9.0\times{10^9}$$ years

$$13.5\times{10^9}$$ years

$$4.5\times{10^9}$$ years

$$4.5\times{10^{4.5}}$$ years

## Questions 47 of 50

Question:Radium has atomic weight 226 and a half-life of 1600 years. The number of disintegrations produced per second from $$1gm$$ are

$$4.8\times{10^{10}}$$

$$9.2\times{10^6}$$

$$3.7\times{10^{10}}$$

Zero

## Questions 48 of 50

Question:The activity of radio isotope changes with

Temperature

Pressure

Chemical environment

None of these

## Questions 49 of 50

Question:A certain nuclide has a half-life of 25 minutes. If one starts with 100 g of it, how much of it will remain at the end of 100 minutes

1.0 g

4.0 g

6.25 g

12.50 g

## Questions 50 of 50

Question:If 8.0 g of a radioactive substance has a half-life of 10 hrs., the half life of 2.0 g of the same substance is