A small bottle contains powdered beryllium Be & gaseous radon which is used as a source of α -particles. Neutrons are produced when α -particles of the radon react with beryllium. The yield of this reaction is 1 4000 i.e. only one α -particle out of 4000 induced the reaction. Find the amount of radon R n 222 originally introduced into the, source, if it produces 1 . 2 × 10 6 neutrons per second after 7 . 6 days. T 1 2 of R n = 3 . 8 days]

Let the amount of R x 222 be N 0 N 7 . 6 = N 0 2 2 = N 0 4 Nuclei left after 7 . 6 day = N 0 4 Decay constant = ln 2 t 1 2 = 0 · 693 3 · 8 × 24 × 3600 s λ = 2 . 11 × 10 - 6 sec Activity = N 0 4 λ = No. Of α particles = N 0 × 2 . 11 × 10 - 6 4 × 4000 = 1 . 2 × 10 6 N 0 = 9 . 095 × 10 15 nuclei = 3 . 354 × 10 - 6 g

HARD

JEE Main/Advance

IMPORTANT

Earn 100

A radioactive nuclide is produced at a constant rate x nuclei per second. During each decay, $E_{0}$ energy is released $50 %$ of this energy is utilised in melting ice at $0 ° C$ . Find mass of ice that will melt in one mean life. $(λ =$ decay constant, $L_{1} =$ Latent heat of fusion.)

Important Questions on Nuclear Physics

EASY

JEE Main/Advance

IMPORTANT

Beta Question Bank for Engineering: Physics>Chapter 34 - Nuclear Physics>Exercise-4>Q 3

In a fusion reactor the reaction occurs in two stages (i) Two deuterium $({}_{1}^{2}D)$ nuclei fuse to form a tritium $({}_{1}^{3}T)$ . nucleus with a proton as product. The reaction may be represented as $D (D, p) T$ . (ii) A tritium nucleus fuses with another deuterium nucleus to form a helium $({}_{2}^{4}H e)$ nucleus with neutron as another product. The reaction is represented as $T (D, n) α$ . Find:

(i) the energy release in each stage.

(ii) The energy release in the combined reaction per deuterium &

(iii) What % of the mass of the initial deuterium is released in the form of energy.

Given: $({}_{1}^{2}D) = 2.014102 u; ({}_{1}^{3}T) = 3.016049 u; ({}_{2}^{4}H e) = 4.002603 u; ({}_{1}^{1}P) = 1.00785 u; ({}_{0}^{1}n) = 1.008665 u$

HARD

JEE Main/Advance

IMPORTANT

Beta Question Bank for Engineering: Physics>Chapter 34 - Nuclear Physics>Exercise-4>Q 4

The element curium

{}_{96}^{248}C m

has a mean life of

10^{13}

second. Its primary decay modes are spontaneous fission and

α

- decay, the former with a probability of

8 %

and the latter with a probability of

92 %

. Each fission releases

200 M e V

of energy. The masses involved in decay are as follows :

{}_{96}^{248}C m = 248.072220 u_{94} {}_{94}^{244}P u = 244.064100 u

and

{}_{2}^{4}H e = 4.002603 u

. Calculate the total power produced. Assume a sample of

10^{20} C m

atom.

HARD

JEE Main/Advance

IMPORTANT

Beta Question Bank for Engineering: Physics>Chapter 34 - Nuclear Physics>Exercise-4>Q 5

A small bottle contains powdered beryllium Be & gaseous radon which is used as a source of

α

-particles. Neutrons are produced when

α

-particles of the radon react with beryllium. The yield of this reaction is

(\frac{1}{4000})

i.e. only one

α

-particle out of

4000

induced the reaction. Find the amount of radon

(R n^{222})

originally introduced into the, source, if it produces

1.2 \times 10^{6}

neutrons per second after

7.6

days.

[T_{\frac{1}{2}}

R_{n} = 3.8

days]

HARD

JEE Main/Advance

IMPORTANT

Beta Question Bank for Engineering: Physics>Chapter 34 - Nuclear Physics>Exercise-4>Q 6

A body of mass

m_{0}

is placed on a smooth horizontal surface. The mass of the body is decreasing exponentially with disintegration constant

λ

. Assuming that the mass is ejected backward with a relative velocity

v_{0}

. Initially the body was at rest. Find the velocity of body after time t.

HARD

JEE Main/Advance

IMPORTANT

Beta Question Bank for Engineering: Physics>Chapter 34 - Nuclear Physics>Exercise-4>Q 7

A radionuclide with disintegration constant

λ

is produced in a reactor at a constant rate

α

nuclei per sec. During each decay energy

E_{0}

is released.

20 %

of this energy is utilised in increasing the temperature of water. Find the increase in temperature of

m

mass of water in time t. Specific heat of water is

S

. Assume that there is no loss of energy through water surface.

A radioactive nuclide is produced at a constant rate x nuclei per second. During each decay, E0 energy is released 50% of this energy is utilised in melting ice at 0°C. Find mass of ice that will melt in one mean life. (λ= decay constant, L1= Latent heat of fusion.)

Important Questions on Nuclear Physics

Learn and Prepare for any exam you want !

A radioactive nuclide is produced at a constant rate x nuclei per second. During each decay, $E_{0}$ energy is released $50 %$ of this energy is utilised in melting ice at $0 ° C$ . Find mass of ice that will melt in one mean life. $(λ =$ decay constant, $L_{1} =$ Latent heat of fusion.)