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Theory For Notes Making

Objective Assignment

Subjective Assignment

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Theory For Notes Making

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Objective Assignment

1.

The energy of neutron in thermal equilibrium at room temperature is approximately

(a) 5 eV   

(b) 1 eV   

(c) 0.1 eV

(d) 0.025 eV.

Ans  (d)

2.

1 milligram radium has 2.68 × 1018 nuclei. Its half-life is 1620 year. After 3240 year, how many nuclei would have disintegrated?

(a) 1.82 × 1018                               

(b) 1.34 × 1018                                               

(c) 0.67 × 1018                                

(d) 2.01 × 1018.

Ans (d)

3.

Fast neutrons can easily be slowed down by

(a) the use of lead shielding           

(b) passing them through heavy water

(c) elastic collision with heavy nuclei                                           

(d) applying strong magnetic field.

Ans  (b)

4.

What percentage of a radioactive substance is left after 5 half-live

(a) 31%    

(b) 3.12%

(c) 0.3%   

(d) 1%

Ans (b)

5.

Radon has 3.8 day as its half-life. How much radon will be left out of 15 mg mass after 38 day?

(a) 1.515 mg

(b) 0.015 mg

(c) 1.049 mg

(d) 9.327 mg

Ans (b)

Subjective Assignment

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QUIZ

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Created on By physicscart

Alpha, Beta And Gamma Radiation, Law Of Radioactivity (Basic Level)

1 / 10

Alpha rays emitted from a radioactive substance are

2 / 10

Beta rays emitted by a radioactive material are

3 / 10

During a negative beta decay

4 / 10

The radioactivity of a certain radioactive element drops to 1/64 of its initial value in 30 seconds. Its half life is

5 / 10

The fraction f of radioactive material that has decayed in time t, varies with time t. The correct variation is given by the curve

6 / 10

In the given reaction

_{z}{{X}^{A}}{{\to }_{{z+1}}}{{Y}^{A}}{{\to }_{{z-1}}}{{K}^{{A-4}}}{{\to }_{{z-1}}}{{K}^{{A-4}}}

Radioactive radiations are emitted in the sequence

7 / 10

What percentage of original radioactive atoms is left after five half lives

8 / 10

In a radioactive substance at t=0, the number of atoms is 8\times {{10}^{4}}. Its half life period is 3 years. The number of atoms 1\times {{10}^{4}} will remain after interval

9 / 10

Radioactive substance do not emit

10 / 10

The figure shows a graph between \ln \left| {\frac{{{{A}_{n}}}}{{{{A}_{1}}}}} \right| and ln|n|, where {{A}_{n}} is the area enclosed by the nth orbit in a hydrogen like atom. The correct curve is

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