| Q: | A wave of energy E is emitted from a transmitter 10 m from an object. The wavelength is decreased from 1000 nm to 250 nm and the transmitter is moved such that it is 5 m from the object. Which of the following correctly represents the energy of the energy of this new wave? |
The correct answer is D. The key to this question is remembering the relationship between energy and wavelength. The relevant equation is E = hv, where E is energy, h is Planck’s constant, and v is the frequency of the wave. Wavelength is inversely proportional to frequency; waves with shorter wavelengths have higher frequencies. In this case, the decrease in wavelength is four-fold, translating to a four-fold increase in frequency. Energy is directly proportional to frequency, so it will also increase by a factor of four. Distance from the object has no impact on energy.