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Radioactivity and Half-Life

Total questions: 25

Worksheet time: 25mins

Name
Class
Date
1.

What is a half-life?

a)

the time required for one half of the radioactive atoms in a sample to decay

b)

the time required for one third of the radioactive atoms in a sample to decay

2.

What is a Geiger counter?

a)

an instrument that uses sonar to bounce sound waves off the ocean bottom

b)

an instrument that measures vibrations in the ground

c)

an instrument that detects the particles emitted or given off by decaying atoms

3.

When the radioactive atoms in a sample decay by half...

a)

alpha decay

b)

Beta decay

c)

half-life

4.

Uranium238 take _________________for one half-life.

a)

5730 years

b)

20 billion

c)

1.65 million

d)

4.5 billion

5.

The time it takes for 50% of the nuclei in a radioactive sample to decay to its stable isotope is called _____

a)

the daughter product

b)

geologic time

c)

the half-life

d)

the half-time

6.

Half-life

a)

A measurement of the total number of protons and neutrons in an element

b)

atoms of the same element with different numbers of neutrons

c)

The spontaneous release of material from the nucleus of radioactive isotopes

d)

The time it takes for 1/2 of an original radioactive atom to decay

7.

How long is one half life of C-14

a)

5730

b)

11460

c)

17190

d)

28650

8.

After 2 half lives, what percent is the parent isotope?

a)

100%

b)

50%

c)

75%

d)

25%

9.

After 4 half-lives, 1g of a sample of Krypton-85 remains unchanged.  What was the original mass of the sample?

a)

16g

b)

32g

c)

0.0625g

d)

4g

10.

If one has 12 kg of Polonium and it undergoes two half-lives, how much do you have left?

a)

12 kg

b)

3 kg

c)

6 kg

11.

After every half-life, a radioactive atom is

a)

reduced by 50%

b)

decreased by 1/4

c)

increased by 1/2

12.

Daughter atom

a)

the original, unstable radioactive element

b)

stable atom that results from the decay of a radioactive atom

c)

The time it takes for one half of the radioactive atoms in a sample to decay

13.

parent atom

a)

the original, unstable radioactive element

b)

the time it takes for one half of the radioactive atoms in a sample to decay

c)

a subatomic particle that has no charge and is located in the nucleus

14.

What is decay?

a)

a subatomic particle that has no charge located in the nucleus of an atom

b)

a stable atom that results from a radioactive atom

c)

a process in which a radioactive atom releases particles and energy

15.

What is an isotope?

a)

one of several forms of the same atoms; same number of protons but have different number of neutrons

b)

a particle that has no charge and is located in the nucleus of an atom.

c)

energy in the form of waves or particles that is emitted from an object and travels through space or air

16.

What is radiometric dating used for ?

a)

to tell absolute age of a rock or fossil

b)

to tell the relative age of a rock or fossil

c)

a way to tell the age of materials based on measuring radioactive atoms and daughter atoms

17.

This man was poisoned by

a)

half-life

b)

radiation

c)

daughter atoms

d)

Geiger Counter

18.

Does the rate of radioactive decay stay at a constant rate?

a)

no

b)

yes

19.

When is the rate of radioactive decay the fastest?

a)

end

b)

beginning

c)

middle

20.

Marie Curie discovered

a)

Thorium

b)

Polonium

c)

uranium

21.

If the half life of a radioactive element is 100yrs, how long would it take for the radioactivity to reduce by one half?

a)

200yrs

b)

100yrs

c)

50yrs

d)

300yrs

22.

What is the primary factor that determines the half-life of a radioactive isotope?

a)

The temperature of the environment

b)

The initial amount of the isotope

c)

The type of radiation emitted

d)

The stability of the isotope's nucleus

23.

If a sample of Carbon-14 has a half-life of 5730 years, how much of a 100g sample would remain after 11,460 years?

a)

25g

b)

50g

c)

12.5g

d)

6.25g

24.

Which of the following best describes the process of radioactive decay?

a)

The splitting of an atom into smaller parts

b)

The emission of particles and energy from an unstable nucleus

c)

The combination of two nuclei to form a heavier nucleus

d)

The absorption of energy by a stable nucleus

25.

In a laboratory experiment, a scientist measures the half-life of a radioactive substance to be 8 hours. If the scientist starts with a 160g sample, how much will remain after 24 hours?

a)

80g

b)

40g

c)

20g

d)

10g