Phy 102 HW 11,12,13 (Harris)

If 6 x 10^16 J of energy is converted into mass, what is the mass in kilograms? Round your answer to 1 decimal place.

0.7

How many different elements are in a carbon dioxide molecule?

2

How many different elements are in a carbon monoxide molecule?

2

How many electrons are in the outermost shell of magnesium?

2

A certain radioactive isotope placed near a Geiger counter registers 160 counts per second. Eight hours later, the counter registers 10 counts per second. What is the half-life of the isotope?

2 hours

A particular atom has an atomic number of 9. How many electrons are in its 2nd shell?

7

How many electrons are in the outermost shell of chlorine?

7

Control is exercised in a nuclear reactor by

absorbing excess neutrons with control rods

A sphere of pure U-235 will explode if it is

big enough

Which radiation has no electric charge associated with it?

gamma rays

A chain reaction grows when the average number of liberated neutrons that go on to cause further fissions is

greater than one

Uranium-235, uranium-238 and uranium-239 are different

isotopes

Compared to the mass of a uranium nucleus before splitting, the pieces it splits into have

less mass

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

mass and charge

In which of these processes is an element of matter changed into a completely different element?

neither of these

If you were to travel at speeds close to the speed of light, you would notice that your own

neither of these (pulse decreases and shape changes)

There is a greater proportion of carbon-14 in

new bones

The mass of a nucleus is exactly equal to the sum of the masses of its individual

none of these

The rate of radioactive decay is proportional to the

number of nuclei

Light bends when it

passes through a gravitational field and passes a massive star

A ______ is a chain of molecules.

polymer

How many different elements are in a water molecule?

two

An electron in the ground state of an atom has an energy of -30.2 eV. What is the energy of the third excited state? Give your answer in eV, and round to 1 decimal place.

-1.9

A particular atom has an atomic number of 11. How many electrons are in its 3rd shell?

1

A radioactive nucleus with atomic number 102 decays by emitting an electron. What is the nucleus's atomic number after it decays?

103

The orbital radius of the 3rd excited state of an atom is 20.7 angstroms. What is the orbital radius of orbit number 6 in angstroms? Round your answer to 1 decimal place.

46.6

Approximately how many neutrons are in Ag-108?

61

You are riding on a train that is traveling at 70 mph. You throw a pen at your sister in the same direction that the train is moving at a speed of 5 mph. How fast does an observer standing on the ground outside the train see the pen travel?

75 mph

When thorium (atomic number = 90) emits a beta particle, the resulting nucleus has atomic number

91

Einstein's famous equation is

E = mc^2

Which of the following statements is (are) a consequence of Einstein's postulates?

Every observer in every reference frame measures the same value for the speed of light, Moving clocks appear to run slow, Moving objects appear to be contracted along the direction of motion, and Clocks synchronized in one reference frame are not synchronized in any frame moving relative to that reference frame.

True or False: Einstein won the Nobel prize for his theories of relativity.

False

True or False: In the Bohr model of the atom, electrons can orbit the nucleus with any radius.

False

What is the most recent major nuclear reactor accident?

Fukushima

A device that is used primarily to detect nuclear radiation is a

Geiger counter.

Why can't you or I travel at the speed of light?

It would require an infinite amount of energy.

What was Marie Curie's native country?

Poland

What is the lowest energy level in an atom called?

The ground state

Compared to special relativity, general relativity is more concerned with

acceleration, gravitation, and space-time geometry.

Most alpha particles fired at a gold foil pass through undeflected because the

atoms of gold, like any others, are mostly empty space.

Suppose you look at the huge clock on the Big Ben Tower in London and it reads 12 noon. If you could travel away from the clock at the speed of light and view it with a telescope, it would

be frozen at 12 noon

An element will decay to an element with higher atomic number in the periodic table if it emits

beta particle

If an alpha particle and a beta particle have the same energy, which particle will penetrate farther into an object?

beta particle

Your space vehicle is traveling directly away from the earth with a speed of c/2, where c is the speed of light. A light signal is sent from earth. The speed with which this light passes your vehicle, as measured by the crew, is

c

Energy released by the sun results from the process wherein atomic nuclei

combine

In the fissioning of uranium, a chain reaction is caused by

ejected neurons

Which of the following are electrically neutral?

neutrons

Alpha particles are repelled by atomic nuclei because

of the electric force between an alpha particle and the atomic nucleus, closeness of each to each other is not permitted, the force between the alpha particle and the atomic nucleus is opposite to an attractive force, and they both have the same sign of electric charge.

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

one-quarter

In an electrically neutral atom, the number of protons in the nucleus is balanced by an equal number of

orbital electrons

Carbon dating requires that the object being tested contain

organic material

The atomic mass number of an element is approximately the same as the number of its

protons and neutrons

Compared to standard Earth time, there is a physical slowing of your time when you travel at

relativistic speeds, and everyday low speeds.

Your strange friend flies past you in a relativistic spacecraft holding a meterstick and a clock. The meterstick appears too ___ to you, and the clock appears ____ to you.

short, slow

Compared to clocks in a stationary reference frame, clocks in a moving reference frame run

slower