Jeopardy (cp) Subterm 2 Review Topics Covered: Waves Sound Electrostatics Circuits Magnetism Relativity

The Motion of the Ocean A cork on the surface of a pond bobs up and down two times per second on ripples having a wavelength of 8.50 cm. What is the cork’s speed?

The Motion of the Ocean V=fl If the speed of a wave stays the same, what happens to the frequency as the wavelength decreases? The frequency will INCREASE. V=fl

The Motion of the Ocean Mrs. Wright sings toward a cliff in the mountains and the sound is reflected directly back to her. She is standing 170 m from the natural wall. If her music is traveling through air at 340 m/s, how long will it take Mrs. Wright to hear her own echo?

Hear the Music A rather noisy typewriter produces a sound intensity of 1 x 10-5 watts/m2. Find the decibel level of this machine.

Hear the Music During the Macy’s Thanksgiving Day Parade it is 5oC outside. A late parade watcher drives towards the parade at 15 m/s as the parade marches towards her, at 5 m/s. If one of the bands plays a note of 415 Hz, what frequency will she hear? (assume the speed of sound is 334 m/s at 5oC)

Hear the Music A 4.00 m long pipe is half way submerged in room temperature water where the speed of sound is 343m/s in the room. What is the fundamental frequency of the pipe?  = 4L

It’s Shocking! What do the electric field lines look like for the following charge:

It’s Shocking! Two point charges of -1.0 nC and +2.0 nC are separated by a distance of 0.30 m. What is the electric force on each particle? (remember 1nC = 1x10-9 C)

It’s Shocking NEGATIVE An uncharged conductor is supported by an insulating stand. A positively charged rod is brought near the left end of the conductor. The you touch the right side of the conductor with your hand. The What is the charge of the conductor now? NEGATIVE

It’s Shocking An electric field of 2.0x104N/C is directed along the positive x-axis. What is the electric force on an electron in this field? (Qelectron = 1.6x10-19C) Along the negative x-axis

It’s Shocking What is the magnitude and direction of the electric field at a distance of 3.20 m from a –50.0 nC charge?

It’s Shocking Two point charges are 4 cm apart. They are moved to a new separation of 2 cm. By what factor does the resulting mutual force between them change? ½ 2) 2 3) ¼ 4) 4 5) depends on the charges

It’s Shocking Charge A has 10 electric field lines coming out, Charge B has 20 lines coming out, and charge C has 30 lines coming in. Which pair of these charges will have the largest force between them if placed 1 cm apart? Charge A 10 lines Charge B 20 lines Charge C 30 lines

Charging by Conduction It’s Shocking A negative rod is used to give an electroscope a negative charge. What type of charging is this? Charging by Conduction

It’s Shocking The leaves of a negative electroscope will stick out. What happens to the leaves when another negative rod is brought close to the scope, but does not touch it? More negatives are pushed into the leaves and the leaves stick out even further. - - - - - - - -

Viva la resistance Long or short Thick or thin Rubber or Aluminum What type of wire makes the best conductor? Long or short Thick or thin Rubber or Aluminum

When resistors are put in series, their overall resistance is Viva La Resistance When resistors are put in series, their overall resistance is a. Larger than that of any individual resistor b. The same as the resistance of one of the resistors c. Smaller than the resistance of any of the resistors

Viva La Resistance A wire 5.0 m long and 3.0 mm in diameter has a resistance of 100 W. A 15 V potential difference is applied across the wire. What is the current in the wire?

Viva La Resistance What is the resistance of a 100. W light bulb if it is plugged into a 120. V outlet?

Viva La Resistance Three resistors with resistance of 6 , 12 , and 24  are connected in series. What is the total resistance of the circuit?

Viva La Resistance What is the same in a parallel circuit? Voltage

Viva La Resistance Three resistors with resistance of 6.0 , 12 , and 24  are connected in series with a 12V battery. What is the current through the 12  resistor? The current is the same through all of them so the total resistance must be used.

Viva La Resistance What is the current through each of the resistors? (Don’t raise your hand until you have all THREE resistances) 6  12  6  12 V / 6  = 2 A 12 V / 18  = 0.67 A 12  12 V

Opposites Attract What is the direction of the force on the electron? . . . . . . . . .

Opposites Attract What does the magnetic field look like for a loop of wire with a clockwise current as shown? X X Into the board inside the loop, out of the board outside the loop

Opposites Attract An electron moves with a speed of 7.0 x 106 m/s along the +x axis. It enters a region where there is a magnetic field of 2.5 T, directed at an angle of 60 to the +x axis and lying in the xy plane. Calculate the magnetic force of the electron.

Opposites Attract Into the page A proton is released such that its initial velocity is from right to left across this page. The proton's path, however, is deflected (by a force) in a direction toward the bottom edge of the page due to the presence of a uniform magnetic field. What is the direction of this field? Into the page

Opposites Attract A generator is created by moving a 0.300 m long wire in an external magnetic field of 5.50 T at a speed of 15.0 m/s. (a) What EMF is produced by the generator? (b) What effective emf if produced by the generator? (a) (b)

Everything’s Relative Einstein’s theory of relativity is based in part on which one of the following postulates? Mass and energy are equivalent. Space and time are absolutes. Energy is conserved only in elastic collisions. Speed of light in a vacuum is the same for all observers regardless of velocity Speed of light in a vacuum is the same at any wavelength.

Everything’s Relative A rocket ship is 80.0 m in length, when measured before leaving the launch pad. What would its velocity be if a ground observer measured its length as 60.6 m while it is in flight?

Everything’s Relative A knight on horseback holds a 10.-m lance. The horse can run at 0.70 c. How long will the lance appear to a person that is standing still on the ground as the horse runs past?

Everything’s Relative A muon formed high in the Earth’s atmosphere travels at a speed of 0.990 c for a distance of 4.60 km (as we see it from Earth) before it decays. Observers on Earth believe it takes the muon 1.55x10-5 seconds to reach Earth’s surface. How long does it take in the frame of the muon??

FINAL JEOPARDY Teams, Place Your Bets

Final Jeopardy What is the current in the 10 W resistor?