Physics Unit 7

When U-235 undergoes fission, the two nuclei that result have a total of

92 protons

The fusion torch is a version of

a mass spectrometer

The function of graphite in the first atomic reactor was to

absorb fast neutrons

Control is exercised in a nuclear reactor by

absorbing excess neutrons with control rods

Atoms can be excited by

all of these

When uranium-238 absorbs a neutron, it

becomes a beta emitter

Which has more energy per photon?

blue light

Present-day research in nuclear fusion uses

both of these

Two photons have the same wavelength. They also have the same

both of these

When an alpha particle is ejected from a nucleus, the nucleus then has less

both of these

Carbon 14 is produced in the atmosphere principally by

cosmic-ray bombardment

The most harmful radiations are those that

damage living cells

The variety of colors seen in a burning log come from the variety of

electron transitions in various atoms

Once an alpha particle is outside the nucleus it is

electrostatically repelled

The most abundant element in the universe is

hydrogen

Electrons with the greater potential energies with respect to the atomic nucleus are

outer electrons

The nucleus with the greatest mass is

plutonium

Compared to the wavelengths of visible light, the wavelengths of matter waves are relatively

small

Light behaves primarily as a wave when it

travels from one place to another

It's impossible for a hydrogen atom to emit an alpha particle

true

The mass of a nucleon is greatest where its potential energy is

greatest

Electrical forces inside a nucleus contribute nuclear

instability

Light behaves primarily as a particle when it

interacts with matter

The energy release in both fission and fusion is mainly in the form of

kinetic energy of fragments

Compared to the sum of the masses of all the individual nucleons in their separate states that make up a nucleus, the mass of the composite nucleus is

less

The half-life of an isotope is one day. At the end of two days the amount that remains is

one-quarter

The difference in the mass of a nucleon when outside an atomic nucleus compared to inside the nucleus depends on

the atomic number of the nucleus

The half lives of elements beyond uranium are too short for these elements to occur in natural deposits. But elements below uranium that have equally short half lives do occur in natural deposits. This is because they are

the products of uranium decay

Which color of light carries the most energy per photon?

violet

If the energy levels in the neon atom were not discrete, neon signs would glow

white