Tag: energy production

Questions Related to energy production

The critical mass of fissionable $U^{235}$ can be reduced by

chemistry energy production nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. adding impurities

  2. heating material

  3. surrounding it by a neutron-reflecting material

  4. surrounding it by a neutron-absorbing material

Show answer
Correct Option: C
Explanation:

Surrounding a spherical critical mass with a neutron reflector reduces the mass needed for criticality.
A common material for a neutron reflector is beryllium metal.

Assertion (A) : Fragments produced in the fission of $U^{235}$ are radioactive
Reason (R) : The fragments have abnormally high proton to neutron ratio

chemistry energy production nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. Both A and R are true and R is correct explanation of A

  2. Both A and R are true and R is not correct explanation of A

  3. A is true but R is false

  4. A is false but R is true

Show answer
Correct Option: C
Explanation:

Fragments produced in the fission of $U^{235}$ are radioactive.
The fragments have the neutron of proton ratio about 1.6.
So, Assertion is correct but reason is false.

Consider the following statements A and B and identify the correct statements. 
Statement A : $p-n; p-p; n-n$ forces between nucleons are not equal and charge dependent
statement B : In nuclear reactor the fission reaction will be in accelerating state if the value of neutron reproduction factor is $k>1$

chemistry energy production nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. Both A and B are correct

  2. Both A and B are wrong

  3. A is wrong B is correct

  4. A is correct B is wrong

Show answer
Correct Option: C
Explanation:

Nuclear forces is charge independent
i.e. $F _{pp} = F _{pn} = F _{nn}$
If the K>1 the fission reaction will be in accelerating state.
So, correct choice is option C.

Which of the following are used as Control Rods :


a) Boron rods
b) Cadmium rods
c) Copper rods

chemistry energy production nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. a is correct

  2. b is correct

  3. c is correct

  4. a,b are correct

Show answer
Correct Option: D
Explanation:

Cadmium and Boron rods are used as control rods in a nuclear reactor as , they are capable of absorbing many neutrons without themselves fissioning.
So, correct choice is option D.

Thermal neutrons are 

chemistry energy production nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. Prompt neutrons

  2. Slow neutrons

  3. Neutrons which are in the nucleus

  4. Neutrons from the sun

Show answer
Correct Option: B
Explanation:

Slow moving neutrons are called thermal neutrons.
So, correct choice is option B.

In a critical chain reaction, energy is released at

chemistry energy production nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. increasing rate

  2. steady rate

  3. decreasing rate

  4. none

Show answer
Correct Option: B
Explanation:

In a critical chain reaction $K=1$,
where $K$ is the reproduction factor defined as the ratio of number of neutrons in any particular generation to the number of neutrons in the preceding generation.
As $K$ is $1$, energy is released in steady state.

The coefficient of transmission for an ideal black body is :

physics energy production perfectly black body black-body radiation black body radiation

  1. infinity

  2. zero

  3. 1

  4. more than one

Show answer
Correct Option: B
Explanation:

Ideal black body absorbs all the radiation, no transmission, no reflection.

Out of the following, which body is not an ideal black body?

physics energy production perfectly black body black-body radiation black body radiation

  1. Wein's black body

  2. Ferry's black body

  3. coal

  4. sun

Show answer
Correct Option: C
Explanation:

wein's and ferry's black bodies are well defined in there papers and sun can also be considered as black body because it is very good emitter. but coal is just a normal carbon compound and neither is it a good absorber or emmiter

Read the following statements carefully
(A) Black body radiation is white
(B) Emissivity of a body is equal to its absorptive power
Mark correct option:

physics energy production perfectly black body black-body radiation black body radiation

  1. Statement (A) is correct

  2. Statement (B) is correct

  3. Both are correct

  4. Both are wrong

Show answer
Correct Option: C
Explanation:
  • (A) The combination of radiation of all the visible wavelengths makes white light. Hence black  body radiation is white

(B) Emissivity of body is equal to it's absorptive power, it is not less then absorptive power or greater than absorptive power
  • Hence both the statements are true
  • Hence option C is the right answer
           

The absorptivity of Lamp black is:

physics energy production perfectly black body black-body radiation black body radiation

  1. 0.91

  2. 0.98

  3. 1.00

  4. 0.99

Show answer
Correct Option: C
Explanation:

Black body is a body which absorbs and emit all types of radiations completely. Since we know that lamp black is perfect black body so its absorptivity is $1.00$