Physics 1140 Test
Write Benjamin Franklin's 3 laws of static electricity.
1. Bodies charged with static electricity attract uncharged bodies. 2. Like electric charges repel one another. 3. Unlike electric charges attract one another.
What type of surface radiates and absorbs heat most efficiently?
A rough, black surface
What statement is most consistent with Lord Rayleigh's beliefs?
Earth was created by God, Who reveals its wonders to men who study His works.
State Huygens' principle of wave motion
Every point on a wave is itself a source of a new wave motion of the same frequency
List the 3 ways an object can acquire a static electrical charge.
Friction, direct contact, induction
List 3 good insulators and 3 good conductors:
Insulators: mica, porcelain, glass Conductors: silver, gold, copper
Two charged spheres are a fixed distance apart. If the charge on one sphere is increased from 3.2 coulombs to 9.6 coulombs, the force that it exerts on the other sphere becomes how many times as great?
Refer to problem P(41) in Pace for a similar solution
The greatest force of repulsion would occur if a positive charge of 35 units were placed a distance of _______.
Refer to problem P(42) in Pace for a similar solution
Two objects with opposite charges of 600 esu are placed 75 cm apart. What is the force of attraction between them?
Refer to problem P(44) in Pace for a similar solution
Two objects, each with a negative charge of 300 esu, are 100 cm apart. What is the force of repulsion between the two objects?
Refer to problem P(44) in Pace for a similar solution
State Coulomb's law
The force acting between two charges is inversely proportional to the square of the distance between them.
Briefly explain the light and dark bands in Thomas Young's experiment.
The light bands resulted where light waves arrived in phase and strengthened one another; the dark bands resulted where light waves arrived out of phase and canceled one another.
Describe an electric field
The region of force that surrounds a charged object
Explain why scientists have difficulty discovering truth.
They have limited means of observing reality
State the law of conservation of charge
electric charge can neither be created nor destroyed
negative rod brought near, leaves diverge farther
negative electroscope
positive rod brought near, leaves collapse quickly
negative electroscope
negative rod brought near, leaves diverge
neutral electroscope
neutral ground brought near, nothing happens
neutral electroscope
positive rod brought near, leaves diverge
neutral electroscope
negative rod brought near, leaves collapse quickly
positive electroscope
neutral ground brought near, leaves collapse slowly
positive or negative
Define capacitance
the ability of a device to hold a charge
What are light waves?
the regular and rapid transverse vibrations of electric and magnetic fields that spread out evenly in all directions.
What was the first useful purpose found for electricity?
the telegraph
