Chain Reaction of Uranium

Q.

Why is a cadmium rod used as an absorbing material to control the reaction rate of neutrons in a nuclear reactor?

Q.

Which radioactive radiations have the least penetrating power?

Q.

What is the value of the speed of gamma radiations in air or vacuum?

Q. A fission reaction is given by $\underset{92}{236}U\to \underset{54}{140}Xe+\underset{38}{94}Sr+x+y$, where x and y are two particles. Considering $\underset{92}{236}U$ to be at rest, the kinetic energies of the products are denoted by $K_{X{e}^{\prime }},K_{S{r}^{\prime }}{K}_x\left(2MeV\right)$ and $K_y\left(2MeV\right)$, respectively. Let the binding energies per nucleon of $\underset{92}{236}U,\underset{54}{140}Xe$ and $\underset{38}{94}Sr$ be 7.5 MeV, 8.5 MeV and 8.5 MeV, respectively. Considering different conservation laws, the correct option(s) is (are)

1. $x=n,y=n,K_{Sr}=129MeV,$K_{Xe} = 86 MeV$
2. $x=p,y=e^{-},K_{Sr}=129MeV,$ K_{Xe} = 86 MeV$
3. $x=p,y=n,K_{Sr}=129MeV,$ K_{Xe} = 86 MeV$
4. $x=n,y=n,K_{Sr}=86MeV,$ K_{Xe} = 129 MeV$

Q.

In nuclear reactions, we have the conservation of

1. Mass only

2. Energy only

3. Momentum only

4. Mass, energy and momentum

Q. In a uranium reactor whose thermal power is $P=100\text{MW}.$ If the average number of neutrons liberated in each nuclear splitting is $2.5$ each splitting is assumed to release an energy $E=200\text{MeV}.$ The number of neutrons generated per unit time is

1. $4.5\times {10}^{18}$
2. $8.9\times {10}^{23}$
3. $8.4\times {10}^{19}$
4. $7.8\times {10}^{18}$

Q.

Name the radiation which is responsible for the maximum biological damage.

Q. 8. What is the difference between the role played by moderator and control rod in a nuclear reactor? Send pdf

Q. With the help of schematic diagram, explain the chain reaction , due to fission of uranium nuclei?

Q. The value of $A$ and $Z$ in the following nuclear reaction is

${}_{12}^{25}\text{Mg}{+}_2^4\text{He}{\to }_1^1\text{H}{+}_Z^A\text{X}$

1. $A=28,Z=13$
2. $A=14,Z=2$
3. $A=36,Z=16$
4. $A=14,Z=8$

Q.

How dangerous is Gamma Radiation?

Q.

What are the 3 types of radiation?

Q. According to Einstein's special theory of relativity -

1. Mass and energy are not related.
2. Mass is another form of energy.
3. Mass is not a form of energy.
4. Mass and energy are conserved separately in a reaction.

Q.

Which is the most ionising radiation?

Q. Why only cadmium rods are used in nuclear reactor

Q.

A mixture of radioactive substances gives off three types of radiations. Name the radiation which travels with the speed of light.

Q. Thermal neutrons are

1. Neutrons which are in the nucleus
2. Neutrons from the sun
3. Prompt neutrons
4. Slow neutrons

Q.

The most penetrating component of radioactive radiation are the ___________ rays.

Q.

Atom bomb is based on the property of fission.

1. True
2. False

Q. 200 MeV energy is released when one nucleus of ${}^{235}U$ undergoes fission. The number of fissions per second required for producing a power of 1Megawatt is :

1. 3.125 x 10${}^{12}$
2. 3.125 x 10${}^{16}$
3. 3.125 x 10${}^{10}$
4. 3.125 x 10${}^8$

Q. The material that slows down the neutrons in the nuclear reactor is called

1. Reduced
2. Compressor
3. Moderator
4. None of these

Q. Which of these statements are correct regarding Uranium isotopes?

1. U-238 is the most abundant isotope of Uranium
2. U-238 is more stable than the U-235
3. U-236 is not found in nature due to high instability
4. U-235 is majorly used as the nuclear fuel

Q. The amount of $U^{235}$ to be fissioned, to operate a $10kW$ nuclear reactor is (Approximately)

1. $1.2\times {10}^{-5}gm/s$
2. $1.2\times {10}^{-11}gm/s$
3. $1.2\times {10}^{-9}gm/s$
4. $1.2\times {10}^{-7}gm/s$

Q. ${}_{92}^{235}U{+}_0^{1}n{⟶}_{56}^{139}Ba{+}_{36}^{94}Kr+3_o^{1}n+200MeV$. Total energy released (in MeV) after $5^{th}$ stage of fission is

1. 48600
2. 16200
3. 24200
4. None of these

Q. When ${}_{92}{U}^{235}$ undergoes fission by absorbing ${}_0{n}^1$ producing ${}_{56}B{a}^{144}$ and ${}_{36}K{r}^{89}$ The number of neutrons produced will be

1. $0$
2. $2$
3. $3$
4. $1$

Q.

What amount of energy is released in the fission of ${}_{92}\mathrm{U}^{235}$ ?

Q. Slow neutrons are sometimes referred to as thermal neutrons because they are :

1. sort of heat radiations
2. in thermal equilibrium
3. capable of generating heat
4. having energies similar to nuclei in thermal motion

Q. What is a thermal neutron? What is its importance?

Q. Which of the following are used as nuclear fuel?

1. ${}_{82}{Pb}^{208}$
2. ${}_{92}{U}^{235}$
3. ${}_{92}{U}^{238}$
4. Both (B) and (C)

Q. The ratio $r$ of the rate of production of neutrons from uranium nucleus to the rate of leakage of neutrons for sustained chain reaction is

1. $r>1$
2. $1>r$
3. $r^2$ = $1$
4. $1>r^2$