PHYS 108: Physical Science II Test 4

Consider a spaceship that moves toward you at .3c (three-tenths the speed of light). It fires a probe toward you, relative to itself, at .3c. Relative to you, the probe approaches at about

.55c

The length of a meterstick projected like a spear at .87c is seen by a person at rest to be about

.5m

Consider a spaceship that moves toward you at .5c (half the speed of light). It fires a probe toward you, relative to itself, at .5c. Relative to you, the probe approaches at about

.8c

Suppose your friend flies by you in a rocket ship traveling at .995c. How many seconds does your clock advance during the time you see his clock advance 1 second

10 seconds

The half life of carbon 14 is 5730 years. If a 1-gram sample of old carbon is 1/8 as radioactive as 1-gram of a current sample, then the age of the old sample is about

17200 years

alpha particles decrease the mass of an element by ____ and the charge by___

4 2

A certain radioactive isotope placed near a Geiger counter registers 160 counts per second. Eight hours later, the counter registers 40 counts per second. What is the half life of the isotope?

4 hours

In a one-g gravitational field, in one second, a light beam will curve beneath a perfectly straight line by

4.9m

When radium (A=88) emits an alpha particle, the resulting nucleus has atomic number

86

one g =

9.8 meters per second

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

91

What are characteristics of nuclear fusion power plants

Virtually no pollution, a working fusion reactor has not been built yet, and no risk of a reactor meltdown

Alpha particles can be stopped by

a few sheets of paper, a sheet of aluminum, and a thick clock of lead

An alpha particle is _____ A beta particle is _____ and a gamma ray is _____

a helium nucleus an electron a photon

If you use the relativistic velocity-addition formula to add everyday velocities, you will get

a result almost identical to the classical result

Control is exercised in a nuclear reactor by _____

absorbing excess neutrons with control rods

Event A occurs before event B in a certain frame of reference. In another frame of reference, event A could occur _____

after event B or simultaneously with event B

Einstein's theory of gravitation obeys the correspondence principle because it

agrees with proven results of Newton's theory

According to the principle of equivalence, observations made in a Newtonian gravitational field are indistinguishable from observations made in

an accelerating reference frame

Space in the local area around a star is

closed, or sphere shaped

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

combine

The most harmful radiations are those that

damage living cells

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

ejected neutrons

According to Einstein's theory of special relativity, _____

energy and mass are aspects of each other AND space and time are aspects of each other

A spaceship that is traveling at 0.5c with respect to your frame of reference, fires a photon beam that travels at a speed c with respect to the spaceship. You measure the photon beam's speed to be _____

equal to c

At the top of a very tall skyscraper, a sensitive watch will appear to run

fast

If lead were used as nuclear fuel, it would be best _____

fissioned

A nuclear process that has relatively few radioactive by-products is _____

fusion

Compared to special relativity, general relativity is more concerned with

gravitation, space-time geometry, and acceleration

Which of the following is not a factor in determining whether a nucleus is stable (non-radioactive) or unstable (radioactive)?

gravitational force

Detonation of a fusion type of hydrogen bomb is started by _____

igniting a small fission bomb

beta particles ___ the charge in an element by __

increase by 1

As the speed of an object approaches c, the speed of light, the relativistic momentum of that object approaches

infinity

when electrons are added or subtracted it becomes an

ion

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

less mass

The frequency of light emitted from helium atoms on the surface of the sun will be _____ the frequency of light emitted by helium on Earth

lower than

Most of the radioactivity from man-made sources that we personally encounter comes from ____

medical x-rays

According to the special theory of relativity, all laws of nature are the same for the 'special' case of reference frames that _____

move at constant velocity

According to the special theory of relativity, all laws of nature are the same in reference frames that

move at constant velocity

If iron were used as a fuel it would be better fissioned or fussioned?

neither

There is an upper limit on the speed of a particle. This means there is also an upper limit on its

neither of these (kinetic energy, momentum)

Different isotopes of an element have different numbers of _____

neutrons

The half-life on an isotope is two days. At the end of four days, how much of the isotope remains?

one-quarter

According to special relativity, one can travel at increased rates

only forward in time

carbon dating requires that the object being tested contain _____

organic material

According to relativity theory, if a space trip finds a son or daughter biologically older than his son or her parents, then the space trip is taken by the

parents

Light bends when it

passes through a gravitational field AND is observed from an accelerated reference frame

light bends when it

passes through a gravitational field, or passes a massive star

The operation of a cloud chamber does not rely on _____

polarization

Detonation of a fission type atomic bomb is started by

pressing together several small pieces of uranium

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

protons

You and a friend share the same space time when there is no

relative velocity between you

Fusing two helium nuclei yields a net

release of energy

A woman standing on the ground sees a rocket ship move past her at 95% of the speed of light. Compared to when the rocket is at rest, the woman measures the rocket's length as

shorter

Compared to clocks in a stationary reference frame, clocks in a moving reference frame runs _____

slower

From a general relativistic point of view, a person on the ground floor of a skyscraper ages

slower than a person the the top floor

When a beta particle is ejected from a nucleus, the nucleus then has slightly

smaller mass and significantly greater charge

When a beta particle is ejected from a nucleus, the nucleus then has slightly _____

smaller mass and significantly greater charge

What are beneficial application of radioactivity?

strong doses of radioactivity for cancer treatment radioactive tracers in crop fertilizer irradiation of the food supply

The main influence working to hold nuclei together is the _____ and a main influence working to break them apart is the _____

strong force electromagnetic

Cocks on a space ship moving very fast relative to the Earth run fast when viewed from

the Earth

Most of the radioactivity from the natural sources that we personally encounter come from

the Earth's crust

Parents can be biologically younger than their children if

the parents take a fast round trip space trip

A gamma ray is emitted from a nucleus when

there is a transition between energy levels in the nucleus