A positively-charged object with a mass of 0.188 kg oscillates at the end of a spring, generating ELF (extremely low frequency) radio waves that have a wavelength of 3.47 × 107 m. The frequency of these radio waves is the same as the frequency at which the object oscillates. What is the spring constant of the spring? Number i Units

An electromagnetic wave has a frequency of 12 MHz. What is its wavelength in vacuum?

Radar is used to determine distances to various objects by measuring the round-trip time for an echo from the object. (a) How far away is the planet Venus if the echo time is 1000 s? (b) What is the echo time for a car 75.0 m from a Highway Police radar unit? (c) How accurately (in nanoseconds) must you be able to measure the echo time to an airplane 12.0 km away to determine its distance within 10.0 m?

Bats use sound waves to catch insects. Bats can detect frequencies up to 100 kHz. If the sound waves travel through air at a speed of v=343 m/s, what is the wavelength of the sound waves?

A sound speaker is rated at a voltage of P=120.00 V and a current of I=10.00 A. Electrical power consumption is P=IV . To test the speaker, a signal of a sine wave is applied to the speaker. Assuming that the sound wave moves as a spherical wave and that all of the energy applied to the speaker is converted to sound energy, how far from the speaker is the intensity equal to 3.82 W/m2?

An entrepreneur decides to invent and market a device that will fool the Doppler radar units used to detect cars that are speeding. The device would be placed at the very front of the car and would detect the radar signal, determine its frequency, and transmit back its own radar signal that would make the radar unit register a legal speed. What would the frequency of the "fake'' signal have 10 be in comparison to the original? If a second unit were designed to be placed at the back end of the car, what would be different about the frequency it would have to use compared to that used by the unit at the from?

The Sun’s energy strikes Earth at an intensity of 1.37kW/m2 . Assume as a mode! approximation that all of the light is absorbed. (Actually, about 30% of the light intensity is reflected out into space.) (a) Calculate the total force that the Sun’s radiation exerts on Earth. (b) Compare this to the force of gravity between the Sun and Earth. Earth’s mass is 5.9721024 kg.

Radio station WWVB, operated by the National Institute of Standards and Technology (NIST) from Fort Collins, Colorado, at a low frequency of 60 kHz, broadcasts a time synchronization signal whose range covers the entire continental US. The timing of the synchronization signal is controlled by a set of atomic clocks to an accuracy of 101012 s, and repeats every 1 minute. The signal is used for devices, such as radio-controlled watches, that automatically synchronize with it at preset local times. WWVB's long wavelength signal tends to propagate close to the ground. (a) Calculate the wavelength of the radio waves from WWVB. (b) Estimate the error that the travel time of the signal causes in synchronizing a radio controlled watch in Norfolk, Virginia, which is 1570 mi (2527 km) from Fort Collins, Colorado.

What is wrong with the following expressions? How can you correct them? (a) C=AB , (b) C=AB , (c) C=AB , (d) C=AB , (e) C+2A=B , (f) C=AB , (g) AB=AB , (h) C=2AB , (i) C=A/B , and (j) C=A/B .

Radar is used to determine distances to various objects by measuring the round-trip time for an echo from the object, (a) How far away is the planet Venus if the echo time is 1000 s? (b) What is the echo time for a car 75.0 m from a highway police radar unit? (c) How accurately (in nanoseconds) must you be able to measure the echo time to an airplane 12.0 km away to determine its distance within 10.0 m?