Physics Homework 1

Which statement is wrong?

• There is more tendency for a physical system to evolve to a higher state of disorder

• There is more tendency for a physical system to evolve to higher entropy

• The disorder in a physical system is called entropy

• The entropy of a system is invariant over time

What happens when matter and anti-matter interact with each other?

• They annihilate each other, resulting in the conversion of matter to energy

• They pass through each other

• They annihilate each other, resulting in the loss of energy

• They merge with each other to form a new particle

Which statement is wrong?

• Free neutrons decay into protons, emitting an electron and a(n anti)neutrino

• Electrons in an atom orbit around the nucleus

• Protons and electrons have three quarks each

• Atoms consist of protons, neutrons, and electrons

How do the temperature and matter density of the Universe change with time?

• Matter density increases but temperature decreases

• Matter density decreases but temperature increases

• They both increase with time

• They both decrease with time

Which of the following is not evidence for the Big Bang?

• Expansion of the Universe

• Observations of clusters of galaxies

• Presence of the Cosmic Microwave Background

• The measured abundance of hydrogen and helium

Which statement is wrong about Planck time?

• After this time, present laws of physics are not valid

• All the forces in the Universe were united in one grand force

• It is the earliest epoch in the history of the Universe

• Studying the Universe before this time requires the theory of quantum gravity

Which of the following is correct?

• The Higgs field is present in some special parts of the Universe

• The Higgs fields are associated with particles called Higgs bosons

• Particles that do not interact with the Higgs field move slower than light

• Particles that do not interact with the Higgs field are more massive

Two electrons interact mostly through the...

• electromagnetic force

• gravitational force

• strong nuclear force

• weak nuclear force

Which of the four fundamental forces keep atomic nuclei from falling apart?

• Weak nuclear force

• Gravitational force

• Strong nuclear force

• Electromagnetic force

The theory of inflation says that...

• Space underwent a slow expansion in a very long period in the early Universe

• Space underwent a rapid compression in a very brief period in the early Universe

• Space underwent a rapid expansion in a very brief period in the early Universe

• Space underwent a slow compression in a very long period in the early Universe