The radioactivity of a sample is A1 at a time t1 and A2 at time t2.  If the mean life of the specimen is T, the number of atoms that have disintegrated in the time interval of t2-t1 is:

1. A1-A2 

2. A1-A2T

3. A1-A2T

4. A1t1-A2t2

Subtopic:  Radioactivity (OLD NCERT) |
 52%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

What is the radius of iodine atom? (atomic no. 53, mass no. 126) [1988]

1. 2.5×10-11 m

2. 2.5×10-9 m

3. 7×10-9 m

4. 7×10-6 m

Subtopic:  Nuclear Binding Energy |
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints

Which of the following statements is true for nuclear forces? [1990]

1. They obey the inverse square law of distance.

2. They obey the inverse third power law of distance.

3. They are short range forces.

4. They are equal in strength to electromagnetic forces.

Subtopic:  Nuclear Binding Energy |
 80%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

The relationship between disintegration constant λ and half-life [T] will be:

1. λ=log10 2T 

2. λ=loge 2T

3. λ=Tloge 2   

4. λ=log2 eT

Subtopic:  Radioactivity (OLD NCERT) |
 75%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

Alpha particles are 

1. 2 free protons

2. helium atoms

3. singly ionized helium atoms

4. doubly ionised helium atoms

Subtopic:  Radioactivity (OLD NCERT) |
 61%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A radioactive sample with a half-life of 1 month has the label: 'Activity = 2 microcurie on 1-8-1991'. What would be its activity two months earlier? 

1. 1.0 microcurie       

2. 0.5 microcurie           

3. 4 microcurie             

4. 8 microcurie

Subtopic:  Radioactivity (OLD NCERT) |
 54%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

If the nuclear force between two protons, two neutrons and between a proton and a neutron is denoted by Fpp, Fnn and Fpn respectively, then:

1. FppFnnFpn

2. FppFnn and Fpn=Fnn

3. Fpp=Fnn=Fpn

4. FppFnnFpn

Subtopic:  Nuclear Energy |
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A radioactive element has half-life period 800 yr. After 6400 yr, what fraction will remain? [1989]

1. 12

2. 116 

3. 18 

4.1256

Subtopic:  Radioactivity (OLD NCERT) |
 77%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

If a proton and anti-proton come close to each other and annihilate, how much energy will be released:

1. 1.5×10-10 J           

2. 3×10-10 J         

3. 4.5×10-10 J         

4. None of these

Subtopic:  Mass-Energy Equivalent |
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

The stable nucleus that has a radius half of the radius of Fe56 is:

1. Li7 

2. Na21

3. S16

4. Ca40

Subtopic:  Nucleus |
 67%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh