NEET (NTA)-National Eligibility cum Entrance Test (Medical) Physics: Questions 1515 - 1519 of 2142

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Passage

Read the passage given below and answer the questions that follow:

In a living organism, the quantity of C 14 is the same as in the atmosphere. But in organisms which are dead, no exchange takes place with the atmosphere and by measuring the decay rate of 14 C in the old bones or wood, the time taken for the activity to reduce to this level can be calculated. This gives the age of the wood or bone.

Given: T 1/2 for 14 C is 5370 years and the ratio of is 1.3 ⨯ 10 -12.

Question number: 1515 (1 of 3 Based on Passage) Show Passage

» Atoms and Nuclei » Radioactive Decay Law

MCQ▾

Question

The decay rate in another piece is found to be 0.30 Bq per gm then we can conclude,

Choices

Choice (4) Response

a.

The observed decay is not that of 14 C alone

b.

There is a statistical error

c.

he sample is very recent

d.

All a. , b. and c. are correct

Question number: 1516 (2 of 3 Based on Passage) Show Passage

» Atoms and Nuclei » Radioactive Decay Law

MCQ▾

Question

The decay rate of 14 C in l gm of carbon in a living organism is,

Choices

Choice (4) Response

a.

25 Bq

b.

0.25 Bq

c.

2.5 Bq

d.

5 Bq

Question number: 1517 (3 of 3 Based on Passage) Show Passage

» Atoms and Nuclei » Radioactive Decay Law

MCQ▾

Question

If in an old sample of wood of 10g the decay rate is 30 decays per minute, the age of the wood is

Choices

Choice (4) Response

a.

15300 years

b.

13310 years

c.

1000 years

d.

50 years

Question number: 1518

» 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.

b.

c.

d.

Question number: 1519

» Thermodynamics » Laws of Thermodynamics » Second Law of Thermodynamics

Assertion-Reason▾

Assertion (Ꭺ)

A room can be warmed by opening the door of a refrigerator in a closed room

Reason (Ꭱ)

Head flows from lower temperature (refrigerator) to higher temperature (room).

Choices

Choice (4) Response

a.

Ꭺ is true but Ꭱ is 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 false

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