Questions from College Physics

Q: Two identical long straight conducting wires with a mass per unit length

Two identical long straight conducting wires with a mass per unit length of 25.0 g/m are resting parallel to each other on a table. The wires are separated by 2.5 mm and are carrying currents in oppos...

Q: In air under ordinary conditions (room temperature and atmospheric pressure),

In air under ordinary conditions (room temperature and atmospheric pressure), the average intermolecular distance is about 4 nm and the mean free path is about 0.1 µm. The diameter of a nitrogen molec...

Q: The carbon isotope 15C decays much faster than 14C. (

The carbon isotope 15C decays much faster than 14C. (a) Using Appendix B.8, write a nuclear reaction showing the decay of 15C. (b) How much energy is released when 15C decays?

Q: A 220 W laser fires a 0.250 ms pulse of

A 220 W laser fires a 0.250 ms pulse of light with a wavelength of 680 nm. (a) What is the energy of each photon in the laser beam? (b) How many photons are in this pulse?

Q: A 640 nm laser emits a 1.0 s pulse in

A 640 nm laser emits a 1.0 s pulse in a beam with a diameter of 1.5 mm. The rms electric field of the pulse is 120 V/m. How many photons are emitted per second?

Q: Multiple-Choice Questions 1–4. In the figure,

Multiple-Choice Questions 1–4. In the figure, four point charges move in the directions indicated in the vicinity of a bar magnet. The magnet, charge positions, and velocity vectors...

Q: A radioactive sample of radon-222 has an activity of 2050

A radioactive sample of radon-222 has an activity of 2050 Bq. How many kilograms of radon are present?

Q: On a warm day, a piano is tuned to match an

On a warm day, a piano is tuned to match an organ in an auditorium. Will the piano still be in tune with the organ the next morning, when the room is cold? If not, will the organ be higher or lower in...

Q: A conducting sphere is placed within a conducting spherical shell. The

A conducting sphere is placed within a conducting spherical shell. The conductors are in electrostatic equilibrium. The inner sphere has a radius of 1.50 cm, the inner radius of the spherical shell is...

Q: A 1500 W electric hair dryer is designed to work in the

A 1500 W electric hair dryer is designed to work in the United States, where the ac voltage is 120 V rms. What power is dissipated in the hair dryer when it is plugged into a 240 V rms socket in Europ...