Forces
Potential Energy
Motors & Generators
Waves
Universe & Tech
100
What happens to the coulombic force between 2 charges when you move them closer together?
stronger
100
When an object is speeding up, its Kinetic Energy is ( increasing / decreasing ) which must be accompanied by (an increase / a decrease ) in Potential Energy.
increasing, a decrease
100
How can you create electricity without a battery or any light?
move a magnet next to a wire
100
What process creates rainbows?
refraction
100
Microphones convert _______ into _______.
sound waves, AC
200
North Poles _______ other North Poles
repel
200
As an object falls toward earth, what is happening to its gravitational potential energy?
decreasing
200
An electric motor converts ______ _______ energy into _____ ______ energy.
electric kinetic, mechanical kinetic
200
During the double slit experiment, first 2 waves diffract. Then what happens?
interference
200
What do the telegraph and telephone mechanics have in common?
magnet and/or electromagnet
300
What can you do to 2 magnets to increase the magnetic force?
move them closer together
300
As a North Pole of a magnet is moving away from another North Pole of a magnet, what is happening to its Magnetic Potential Energy?
decreasing
300
A wire with direct electric current flowing through it pushes magnets ...
(a) parallel to the wire
(b) perpendicular to the wire
(c) back and forth
(b) perpendicular
300
How would this interference pattern look different if it were blue light instead of red?
bright spots would be closer together
why?
because blue is a shorter wavelength than red.
300
antenna convert between _______ and _______.
AC, radio waves
400
A 2 C charge is 0.25 m away from a -5 C charge. How much electrostatic force of attraction do they experience?
(9x109)(2)(-5) / (0.25)2 = 1.44 x 1012 N
400
If a positive charge is moved toward another positive charge, what is happenning to its Electrostatic Potential Energy?
increasing
400
What do we call an machine that uses a moving magnet to create electricity?
Electric Generator
400
Blue light was used to release electrons from a metal. What can be done to increase the speed of the electrons released?
higher frequency light (purple)
400
All the stars are moving (away / toward) us. Evidence for this is the (red / blue) shift of their light spectra.
away, red
500
2 magnets experience 20 N of magnetic force when they are 6 cm apart. How much magnetic force do they experience when they are only 3 cm apart?
20N x 22 = 80 N
500
What is happening to a magnet's gravitational potential energy if another magnet is repelling it upward ... pushing it away from the earth.
its gravitational potential energy is increasing
500
Which one, a microphone or loud-speaker, works using the "electric motor effect"? Explain why.
loud-speaker
converts Electrical Energy (AC) into Mechanical Energy (vibrating diaphram) which creates sound waves
500
Blue light was used to release electrons from a metal. What can be done to increase the number of electrons released?
Brighter light.
500
The half-life of K-40 decaying to Ar-40 is 1.3 billion years. Brand new volcanic ash is 0.0004% K-40. How old is a fossil covered in volcanic ash made of 0.0001% K-40?
2.6 billion years old