Nuclear Fission

Q.

What is a chain reaction?

Q. When ${}_{92}{U}^{235}$ undergoes fission. 0.1% of its original mass is changed into energy. How much energy is released if 1 kg of ${}_{92}{U}^{235}$ undergoes fission

1. $0.9\times {10}^{10}J$
   
2. $0.9\times {10}^{14}J$
   
3. $9\times {10}^{12}J$
   
4. $9\times {10}^{13}J$

Q.

In an α-decay the kinetic energy of α particle is $48MeV$ and Q-value of the reaction is $50MeV$. The mass number of the mother nucleus is: (Assume that daughter nucleus is in ground state)

1. $9$

2. $100$

3. $104$

4. None of these

Q. The combination of two lighter nuclei to produce a heavier nucleus is called:

1. Nuclear fission
2. Nuclear fusion
3. Gamma decay
4. Beta decay

Q.

The energy released in the fission of 1 kg of U-235 is equivalent to energy obtained from the burning of coal weighing ___

1. 2500 ton

2. 25000 ton

3. 25 ton

4. 250 ton

Q.

Why do only big nuclei undergo nuclear fission reaction?

1. Bigger nuclei have very less number of protons which makes them unstable.

2. Bigger nuclei are unstable because of presence of large number of like charge particles.

3. Bigger nuclei have less number of neutron which makes them unstable.

4. In case of bigger nuclei, electron reside inside the nucleus.

Q.

In nuclear fission, the mass of reactants is more than the mass of products.

1. True

2. False

Q. What is the amount of energy released when 1 a.m.u. of mass is lost? Express the energy in terms of MeV.

1. 932.58

Q. What is the source of energy of sun or stars?

Q. The process in which a large nucleus splits into smaller nuclei with release of energy is termed as nuclear .

1. fission
2. fusion
3. decay

Q.

An uncontrolled nuclear chain reaction forms the basis of :
(a) nuclear power plant (b) hydrogen bomb (c) thermal power station (d) atom bomb

Q.

The energy produced inside the star is due to the process called nuclear fusion.

1. True

2. False

Q.

The nuclear energy is measured as___________.

Q.

Nuclear Fission/fusion occurs with destruction of same mass and evolution of large amount of energy.But law of conservation of mass says that mass can neither be created nor be destroyed. How?

Q.

Can Mass be converted into energy ?

Q. When ${}_{92}{U}^{235}$ undergoes fission, 0.1% of its original mass is changed into energy.$9\times {10}^{x}J$ of energy is released if $1kg$ of ${}_{92}{U}^{235}$ undergoes fission, then the value of $x$___

Q. A nuclear power plant generates electric power of 200 MW using the nuclear fusion of U-235. How much uranium is consumed in a day to produce the electric power, if one U-235 nucleus produces 190 MeV of energy?

1. $235\text{g}$
2. $222\text{g}$
3. $105\text{g}$
4. $444\text{g}$

Q.

Explain nuclear fission in brief.

Q.

Can fusion reactors explode?

Q.

Neutrons were discovered by bombarding beryllium with ________ particles.

Q.

In one average-life,

1. half the active nuclei decay

2. less than half the active nuclei today

3. more than half the active nuclei decay

4. all the nuclei decay

Q. Which of the following statement is correct?

1. The rest mass of a stable nucleus is equal to the sum of the rest masses of its separated nucleons
2. The rest mass of a stable nucleus is greater than the sum of the rest masses of its separated nucleons.
3. In nuclear fusion, energy is released by fusing two nuclei of medium mass (approximately 100 a.m.u.)
4. In nuclear fission, energy is released by fragmentation of a very heavy nucleus

Q. The decay constant of ${}^{238}U$ is $1.54\times {10}^{-10}y{r}^{-1}$. What will be the average life of a sample of ${10}^{20}$ such ${}^{238}U$ nuclei?

1. 3.25 billion years
2. 6.49 million years
3. 3.25 million years
4. 6.49 billion years

Q. How is nuclear energy generated? And why is it's large scale use prohibited?

Q. What is nuclear fission ? Explain with an example. Write the equation of the nuclear reaction involved.

Q.

Which of the following is a good nuclear fuel?

1. $Uranium-$$236$

2. $Uranium-$$238$

3. $Thorium-$$236$

4. $Plutonium-$$239$

Q.

A uranium nucleus at rest decays into a thorium nucleus and a helium nucleus, as shown below. Which of the following is true?

${}_{92}^{235}U{\to }_{90}^{231}Th{+}_2^{4}He$

1. Each decay product has the same kinetic energy.

2. The decay products tend to go in the same direction.

3. The thorium nucleus has more momentum than the helium nucleus.

4. The helium nucleus has more kinetic energy than the thorium nucleus.

Q. The particle used in nuclear fission for bombardment is :

1. alpha particle​
2. beta particle​
3. proton​
4. neutron​

Q. (a) A thorium isotope ${}_{90}^{233}Th$ undergoes an $\alpha$ - decay and changes to radium. What are the atomic number and mass number of radium produced?
(b) If radium undergoes further disintegration and emits two $\beta$ - particles, represent the reaction in the form of an equation.
[3 MARKS]

Q. In a conventional nuclear power plant, the energy released from nuclear fission is used to

1. generate electricity
2. cool the moderator
3. heat the control rods
4. merge uranium atoms