Suppose the range for 5.0 MeVa ray is known to be 2.0 mm in a certain material. Does this mean that every 5.0 MeVa a ray that strikes this material travels 2.0 mm, or does the range have an average value with some statistical fluctuations in the distances traveled? Explain.
Suppose the range for 5.0 MeVa ray is known to be 2.0 mm in a certain material. Does this mean that every 5.0 MeVa a ray that strikes this material travels 2.0 mm, or does the range have an average value with some statistical fluctuations in the distances traveled? Explain.
Suppose the range for 5.0 MeVa ray is known to be 2.0 mm in a certain material. Does this mean that every 5.0 MeVa a ray that strikes this material travels 2.0 mm, or does the range have an average value with some statistical fluctuations in the distances traveled? Explain.
Expert Solution & Answer
To determine
Whether it means that every 5.0 MeVαray that strikes this material travels 2.0mm , or the range have an average value with some statistical fluctuations in the distances traveled, suppose the range for 5.0 MeVα ray is known to be 2.0mm in a certain material
Answer to Problem 1CQ
Every 5.0 MeVa a ray that strikes this material won't travel 2.0 mm.
Explanation of Solution
Concept Used:
Nuclear radioactivity.
The distance travel by the radiation through a material is defined as the range of the radiation. The range of radiation depends upon some of the factors which includes the energy of the radiation, the material through which it travels and the type of the radiation whether alpha, beta or gamma ray. By defining these factors or by knowing these factors we can know the range of the radiation. Here it is given that range of radiation is 2 mm for a certain material, But the charged particles in the material interacts with rays and because of that ray will show some random fluctuations, so every 5.0 MeVαray won't travel 2.0mm on the same material. In the α decay the energy released in it is about MeV range. It is about 106 for a typical chemical reaction. Most of the energy is converted in kinetic energy of the α particle which moves at high speed
Conclusion:
Thus, every 5.0 MeVa a ray that strikes this material won't travel 2.0 mm.
Want to see more full solutions like this?
Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Question B3
Consider the following FLRW spacetime:
t2
ds² = -dt² +
(dx²
+ dy²+ dz²),
t2
where t is a constant.
a)
State whether this universe is spatially open, closed or flat.
[2 marks]
b) Determine the Hubble factor H(t), and represent it in a (roughly drawn) plot as a function
of time t, starting at t = 0.
[3 marks]
c) Taking galaxy A to be located at (x, y, z) = (0,0,0), determine the proper distance to galaxy
B located at (x, y, z) = (L, 0, 0). Determine the recessional velocity of galaxy B with respect
to galaxy A.
d) The Friedmann equations are
2
k
8πG
а
4πG
+
a²
(p+3p).
3
a
3
[5 marks]
Use these equations to determine the energy density p(t) and the pressure p(t) for the
FLRW spacetime specified at the top of the page.
[5 marks]
e) Given the result of question B3.d, state whether the FLRW universe in question is (i)
radiation-dominated, (ii) matter-dominated, (iii) cosmological-constant-dominated, or (iv)
none of the previous. Justify your answer.
f)
[5 marks]
A conformally…
SECTION B
Answer ONLY TWO questions in Section B
[Expect to use one single-sided A4 page for each Section-B sub question.]
Question B1
Consider the line element
where w is a constant.
ds²=-dt²+e2wt dx²,
a) Determine the components of the metric and of the inverse metric.
[2 marks]
b) Determine the Christoffel symbols. [See the Appendix of this document.]
[10 marks]
c)
Write down the geodesic equations.
[5 marks]
d) Show that e2wt it is a constant of geodesic motion.
[4 marks]
e)
Solve the geodesic equations for null geodesics.
[4 marks]
Page 2
SECTION A
Answer ALL questions in Section A
[Expect to use one single-sided A4 page for each Section-A sub question.]
Question A1
SPA6308 (2024)
Consider Minkowski spacetime in Cartesian coordinates th
=
(t, x, y, z), such that
ds² = dt² + dx² + dy² + dz².
(a) Consider the vector with components V" = (1,-1,0,0). Determine V and V. V.
(b) Consider now the coordinate system x' (u, v, y, z) such that
u =t-x,
v=t+x.
[2 marks]
Write down the line element, the metric, the Christoffel symbols and the Riemann curvature
tensor in the new coordinates. [See the Appendix of this document.]
[5 marks]
(c) Determine V", that is, write the object in question A1.a in the coordinate system x'. Verify
explicitly that V. V is invariant under the coordinate transformation.
Question A2
[5 marks]
Suppose that A, is a covector field, and consider the object
Fv=AAμ.
(a) Show explicitly that F is a tensor, that is, show that it transforms appropriately under a
coordinate transformation.
[5 marks]
(b)…
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.