# Alpha Decay

## Trending Questions

**Q.**

Write differences between a proton and a positron.

**Q.**What weights of P4O6 and P4O10 will be produced by the combustion of 31 g of P4 in 32 g of oxygen leaving no P4 and O2?

- 17.5 g, 190.5 g
- 2.75 g, 219.5 g
- 55 g, 71 g
- 27.5 g, 35.5 g

**Q.**The rate constant for the first order decomposition of H2O2 is given by the following equation:

log k=14.2−1.0×104KT

Calculate Ea for this reaction and rate constant k of its half-life period be 200 minutes. ( Given: R= 8.314 JK−1mol−1

**Q.**The following facts are available.

2X−+Y2⟶2Y−+X2

2W−+Y2⟶ No reaction

2Z−+X2⟶2X−+Z2

Which of the following statements is correct?

- E0W−/W2>E0Y−/Y2>E0X−/X2>E0Z−/Z2
- E0W−/W2<E0Y−/Y2<E0X−/X2<E0Z−/Z2
- E0W−/W2<E0Y−/Y2>E0X−/X2>E0Z−/Z2
- E0W−/W2>E0Y−/Y2<E0X−/X2<E0Z−/Z2

**Q.**A compound contains two elements ′X′ and ′Y′ in the ratio of Mass percentage of 50% each. Atomic mass of ′X′ is 20 and ′Y′ is 40. What can be its simplest formula?

- XY
- X2Y
- XY2
- X2Y3

**Q.**

Why activation energy should be low in order to have higher rate of reaction?

**Q.**

Which of the following changes occur due to the emission of $\alpha $-particle from an atom of an element?

Atomic number and mass number increase by 2 units and 4 units, respectively.

Atomic number and mass number decrease by 2 units and 4 units, respectively.

Only atomic number increases by one unit.

Only atomic number decreases by one unit.

**Q.**84Po210 (half-life= 138.4 days) undergoes α- decay to form 82Pb206. If 2.1 g of 84Po210 is placed in a sealed tube, what volume (in mL) of helium will accumulate in 69.2 days at STP?(take √2=1.4).

**Q.**α- particles can be detected using

- Zinc sulphide screen
- Barium sulphate
- Thin aluminum sheet
Gold foil

**Q.**

"When an electron is removed from a sodium atom ($\mathrm{Na}$), sodium ion (${\mathrm{Na}}^{+}$) is formed". Is this statement correct? If not, correct it.

**Q.**77. What is the ratio of average molecular kinetic energy of UF6 to that of H2 both at 300k?

**Q.**Among the radioactive elements tritium is used as better tracer because

- It emits low energy -rays
- It does not emit -rays
- It is cheaply available
- All the above

**Q.**The number of neutrons in deuterium is

- 2
- 3
- 1
- 0

**Q.**When E^° Ag+ I Ag 0.80 volt & Zn+2\vert Zn=0.76 volt , which of the following is correct? 1)Ag+ can be reduced by H2. 2)Ag can oxidise H2 into H+ion 3) Zn+2 can be reduced by H2. 4) Ag can reduce Zn+2 ion

**Q.**1.0 g atom of an α − emitting isotope (t1/2=10 days) is sealed in a container. The volume of the gas accumulated in the container at STP after 10 days would be:

- 1.0 L
- 44.8 L
- 11.2 L
- 22.4 L

**Q.**The element Lawrencium (256103Lr) is named after Ernest Lawrence, whose invention - the cyclotron - helped discover many radioactive nuclei. Consider now, the alpha decay of 256103Lr.

256103Lr→abMd+α

Where α represents the alpha particle given out. What are the values of a and b?

- a=252 ; b =105
- a=260 ; b =101
- a=260 ; b =105
- a=252 ; b =101

**Q.**Which of the following is not correct?

- 4020Ca and 4018Ar are isotones
- Nuclei of atoms participate in nuclear reactions
- 1 amu of mass defect is approximately equal to 931.5 MeV
- Uranium (U238) series is known as (4n+2) series

**Q.**

Calculate the number of α- and β-particles emitted when 92U238 changes into radioactive 82Pb206.

(IIT-JEE, 2000)

- 3, 4
- 4, 3
- 6, 8
- 8, 6

**Q.**

If N_{0} active nuclei become $\frac{{N}_{o}}{16}$ in 80 days. Find the half-life of nuclei?

40 days

20 days

60 days

30 days

**Q.**A counter rate meter is used to measure the activity of a radioactive sample. At a certain instant, the count rate was recorded as 475 counters per minute. Five minutes later, the count rate recorded was 270 counts per minute. Calculate the decay constant and half life period of the sample.

**Q.**Which of the following are isoelectronic as well as isostructural?

- NO−3 and CO2−3
- SO3 and NO−3
- ClO−3 and CO2−3
- CO2−3 and SO3

**Q.**AMZ→BM−12Z−1

The number of α and β particles emitted in the above conversion is

- 3α, 5β
- 5α, 6β
- α, 3β
- 2α, 4β

**Q.**The α-particle is identical with

- Helium nucleus
- Hydrogen nucleus
- Electron
- Proton

**Q.**Which of the following is expected to have the highest hydration energy?

**Q.**

A radioactive material decreases by simultaneous emissions of two particles with half life 1620 and 810 years. The time after which (1/4)th of the material remained is:

- 1080 years
- 2000years
- 1500years
- 1200years

**Q.**A radioactive substance does not emit :

- positron
- proton
- α− rays
- β− rays

**Q.**84Po210 (half-life= 138.4 days) undergoes α- decay to form 82Pb206. If 2.1 g of 84Po210 is placed in a sealed tube, what volume (in mL) of helium will accumulate in 69.2 days at STP?(take √2=1.4).

**Q.**At a given instant there are 25 % undecayed radioactive nuclei in a sample. After 10 sec the number of undecayed nuclei remains 12.5 %. Calculate :

( i ) mean − life of the nuclei and

( ii ) The time in which the number of undecayed nuclears will further reduce to 6.25 % of the reduced number.

- ( i )tmeans=14.43s ( ii ) 40 seconds
- ( i )tmeans=1.443s ( ii ) 40 seconds
- ( i )tmeans=14.43s ( ii ) 4 seconds
- None of these

**Q.**The disintegration rate of a certain radioactive sample at any instant is 4750 dpm. Five minutes later, the rate becomes 2700 dpm. The half life of sample is :

- 8.13 min
- 5.13 min
- 4.13 min
- 6.13 min

**Q.**8. If the amount of radioactive substance is increased three times, the number of disintegrated atoms per unit time would?