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### calculating frequency

Posted: **Mon Oct 14, 2019 9:22 pm**

by **SarahSteffen_LEC4**

Say you are asked to calculate the frequency of a photon emitted by a hydrogen atom after making a transition from a higher energy level to a lower energy level. Well when using the Rydberg equation you would get a negative energy because energy is being emitted. But my question is could you get a negative frequency when dividing that negative answer you found using the Rydberg equation by planck's constant, or should frequency always be positive?

### Re: calculating frequency

Posted: **Mon Oct 14, 2019 9:26 pm**

by **Jainam Shah 4I**

The negative sign may be ignored, because negative and positive signs are used only to convey the idea of losing/gaining energy, but not for the actual calculation. A negative simply indicates energy is lost and positive that energy is gained. However, what matters is the actual amount of energy in terms of calculations. We cannot have a negative frequency, because frequency in the number of waves over a given amount of time. We can't have a negative number of waves passing through a specific amount of time.

### Re: calculating frequency

Posted: **Mon Oct 14, 2019 9:30 pm**

by **Nyari Muchaka_Discussion 4A**

Frequency measures the number of times a wave passes through a given point in a given amount of time. Given that fact, frequency cannot be negative as you cannot have a negative number of waves. If you are getting a negative frequency, you can check and see if maybe there are negative on both sides of the equation that should cancel out.

### Re: calculating frequency

Posted: **Mon Oct 14, 2019 10:20 pm**

by **Brynne Burrows 3K**

In terms of frequency, a negative value cannot be obtained because it is the number of waves over a given unit of time. Negative values represent the loss or gain of energy in terms of a change in energy under the Bohr frequency condition.