Questions from College Physics

Q: Current of 83 mA flows through the resistor in the diagram.

Current of 83 mA flows through the resistor in the diagram. (a) What is the resistance of the resistor? (b) In what direction does the current flow through the resistor?

Q: A friend says that electric current “follows the path of least

A friend says that electric current “follows the path of least resistance.” Is that true? Explain.

Q: (a) What fraction of the 238U atoms present at the

(a) What fraction of the 238U atoms present at the formation of the Earth still exist? Take the age of the Earth to be 4.5 × 109 yr. (b) Answer the same question for 235U. Could this explain why ther...

Q: Compare the resistance of an ideal ammeter with that of an ideal

Compare the resistance of an ideal ammeter with that of an ideal voltmeter. Which has the larger resistance? Why?

Q: Air at room temperature and atmospheric pressure has a mass density of

Air at room temperature and atmospheric pressure has a mass density of 1.2 kg/m3. The average molecular mass of air is 29.0 u. How many molecules are in 1.0 cm3 of air?

Q: Io, one of Jupiter’s satellites, has an orbital period of

Io, one of Jupiter’s satellites, has an orbital period of 1.77 d. Europa, another of Jupiter’s satellites, has an orbital period of about 3.54 d. Both moons have nearly circular orbits. Use Kepler’s t...

Q: Suppose a battery is connected to a network of resistors and capacitors

Suppose a battery is connected to a network of resistors and capacitors. What happens to the energy supplied by the battery?

Q: Why are electric stoves and clothes dryers supplied with 240 V,

Why are electric stoves and clothes dryers supplied with 240 V, but lights, radios, and clocks are supplied with 120 V?

Q: Refer to Problem 110. One capacitor plate has an excess of

Refer to Problem 110. One capacitor plate has an excess of electrons and the other has a matching deficit of electrons. What is the number of excess electrons?

Q: A hollow conducting sphere of radius R carries a negative charge −

A hollow conducting sphere of radius R carries a negative charge −q. (a) Write expressions for the electric field / inside (r < R) and outside (r > R) the sphere. Also indicate the direction of the f...