Physical Science 2nd Semester Exam

act of emitting radiation spontaneously

radioactivity

atoms of the same element with different numbers of neutrons

isotope

process where particles are lost from unstable nucleus

radioactive decay

form of energy released from radioactive decay

radiation

where alpha particles is released from nucleus of atom

alpha decay

where an electron or positron is released from nucleus of an atom

beta decay

time required for a quantity to reduce to half its initial value

half-life

reaction in which the nucleus of an atom splits into two or more nuclei. large amounts of energy are released.

nuclear fission

process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus and large amounts of energy.

nuclear fusion

power generated by nuclear reactors

nuclear power

power not generated by nuclear reactors

non-nuclear power

6 Protons, 6 Newtons, and Stable

6 Protons, 7 Newtons, and Stable

6 Protons, 8 Newtons, and Unstable

3 isotopes of carbon

you start with 100g of Francium. 22 minutes later you have 50g remaining. What is the half-life of Francium?

22 minutes

the half-life of Uranium-238 is 4.5 billion years. You start with 100 g of U-238. How much will you have remaining after 1 half-life? 2 half-lifes?

1: 50g. 2: 25g

Pros and Cons of nuclear power

Pros: Low greenhouse gas emissions, high energy density, and stable power generation.

Cons: Production of radioactive waste, high construction costs, and potential for accidents.

3 examples of nuclear power

Power Plants, Space Probes, and the Sun

energy cannot be created or destroyed but it can be changed from one form of energy to another

law of conservation of energy

ability to do work

energy

using a force to move a object a distance

work

a push and pull

force

the rate at which work is done, the amount of energy transferred or converted per unit of time

power

energy that is stored in an object due to its position, charge, stresses, and other factors

potential energy

energy of motion

kinetic energy

energy an object has due to its position above Earth, energy due to its height

gravitational potential energy

energy a magnetic object has due to its position and orientation to other magnetic objects

magnetic potential energy

the energy an electrically charged object has due to its position near other charged objects

electrical potential energy

the energy an object has due to its chemical bonds

chemical potential energy

the energy an object has due to the stretching or compression of an elastic object

elastic potential energy

the energy an object has because of its position and/or motion

mechanical energy

energy created by the movement of charged particles through a closed circuit

electrical kinetic energy

a type of energy that travels in waves and allows us to see

light energy

the energy of moving molecules; people feel this as heat

thermal energy

measure of average kinetic energy of the particles in an object

temperature

instrument that measures and indicates temperature

thermometer

temperature where molecular energy is at a minimum

absolute zero

energy transferred between objects that are at different temperatures

heat

the transfer of energy as heat between objects in direct contact

conduction

the transfer of energy through movement of warm fluids, like air or water

convection

the energy that is transferred as electromagnetic waves

radiation

a material through which energy can be easily transferred as heat

conductor

a material that transfers energy poorly

insulator

the quantity of heat required to raise the temperature of one gram of a substance by one degree Celsuis

specific heat

energy caused by vibrations traveling through matter

sound energy

the quantity of motion of a moving object, product of mass and velocity

momentum

momentum can neither be created nor destroyed, only transferred between objects through interactions, total momentum before a collision is equal to the total momentum after the collision

law of conservation of momentum

an event where two or more objects come into direct contact and exert forces on each other over a short period of time, causing a change in their motion , typically transferring momentum between the objects.

collision

the change in momentum of an object

impulse

example and nonexample of work

Example: Pushing a box across the floor.

Nonexample: Holding a bag

example for each type of potential and kinetic energy

Gravitational Potential Energy: a bird sitting on a tree

Magnetic Potential Energy: a magnet held above an object

Electrical Potential Energy: Battery

Chemical Potential Energy: Dynamite

Elastic Potential Energy: Rubber Band

Mechanical Energy: a moving car

Electrical Kinetic Energy: electrons flowing through wires

Light Energy: sunlight

Thermal Energy: fire

Sound Energy: dog barking

3 examples for conduction, convection, radiation, thermal conductor, and thermal insulator

Conduction: heat from coffee cup heating your hand, burning yourself on a stove, and a metal sliding getting hot in the sun

Convection: a hot air balloon rising, boiling water, and warm air rising above a radiator.

Radiation: feeling the heat of the sun, reheating something in the microwave, and feeling the heat of a stove.

Thermal Conductor: silver, copper, and iron

Thermal Insulators: plastic, glass, and wood.

would a thermal conductor or insulator be better suited for a cooking pan handle? why?

Thermal Insulator because it prevents the heat from being transferred so the handle will stay cool while the pan is hot.

energy transformations for firecracker, phone charger, photosynthesis, car driving, roller coaster cart

Firecracker: chemical to light, heat, and sound

Phone Charger: electrical to chemical

Photosynthesis: light to chemical

Car Driving: chemical to thermal to mechanical to kinetic

Roller Coaster Cart: potential to kinetic

what is the rate of gravity on earth? moon?

Earth: 9.8 m/s^2

Moon: 1.62 m/s^2

formula for potential energy, kinetic energy, work, power, and momentum

PE = mgh. KE = 1/2mv^2. w = Fs. p = W/t. m = mv

units for potential energy, kinetic energy, work, power, and momentum

Potential Energy: joules(J)

Kinetic Energy: joules(J)

Work: joules(J)

Power: watts(W)

Momentum: kilograms-meter per second(kg m/s)

flow of electrons

electricity

gained when an atom gains or loses an electron

electric charge

path that flowing electrons take.

electric current

substance that allows electricity to flow through it

conductor

materials that electricity does not flow through

insulator

path for transmitting electric currents

electric circuit

have a break in currents pathway

open circuit

don't have a break in the current pathway. electrons can flow.

closed circuit

supplies electric power to the circuit

power source

connected to the positive and negative terminals and helps create the pathway for currents to flow through.

wires

the device in a circuit that consumes power

load

pressure from an electrical circuit power source that pushes charged electrons through a circuit

voltage

rate at which electrons flow through a conductor

current

opposition to the flow of an electric current

resistance

all components are connected end to end of one after another to form a single path for current. if it breaks, the circuit won't work.

series circuit

flows through branches

parallel circuit

voltage across a conductor is directly proportional to he current flowing through

ohm's law

how does an atom gain an electric charge

by gaining or losing electrons

3 examples of a good conductor

silver, copper, and gold