Atoms and Nuclei-Radioactivity (NEET Physics): Questions 1 - 5 of 10

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Question number: 1

» Atoms and Nuclei » Radioactivity

MCQ▾

Question

Which of the following are modes of radioactive decay?

(1) Positron emission (2) Electron capture

(3) α -decay (4) Fusion

Select the correct answers and mark it according to the following codes:

Choices

Choice (4) Response

a.

1, 2 and 3 are correct

b.

1 and 3 are correct

c.

1 and 2 are correct

d.

2 and 4 are correct

Question number: 2

» Atoms and Nuclei » Radioactivity

MCQ▾

Question

The radioactivity of an element becomes (14) th of its original value in 60 seconds. Then the value of half-life time is,

Choices

Choice (4) Response

a.

5 sec

b.

20 sec

c.

10 sec

d.

30 sec

Question number: 3

» Atoms and Nuclei » Radioactivity

Assertion-Reason▾

Assertion (Ꭺ)

Amongst α, β and γ - rays, γ has maximum penetrating power.

Reason (Ꭱ)

The α- particle is heavier than β and γ rays.

Choices

Choice (4) Response

a.

Both Ꭺ and Ꭱ are false

b.

Ꭺ is false but Ꭱ is true

c.

Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ

d.

Both Ꭺ and Ꭱ are true but Ꭱ is NOT the correct explanation of Ꭺ

Question number: 4

» Atoms and Nuclei » Radioactivity

MCQ▾

Question

For thorium A = 232 and Z = 90, at the end of some radioactive disintegrations we obtain an isotope of lead with A = 208 and Z = 82. Then the number of α and β particles emitted are,

Choices

Choice (4) Response

a.

α=5,β=5

b.

α=6,β=3

c.

α=4,β=6

d.

α=6,β=4

Question number: 5

» Atoms and Nuclei » Radioactivity

Assertion-Reason▾

Assertion (Ꭺ)

Electron capture occurs more often than positron emission in heavy elements.

Reason (Ꭱ)

Heavy elements exhibit radioactivity.

Choices

Choice (4) Response

a.

Ꭺ is true but Ꭱ is false

b.

Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ

c.

Ꭺ is false but Ꭱ is true

d.

Both Ꭺ and Ꭱ are true but Ꭱ is NOT the correct explanation of Ꭺ

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