## 1B. 5

$E=hv$

Aashka Popat 1A
Posts: 50
Joined: Sat Sep 07, 2019 12:16 am

### 1B. 5

This is the question: The g-ray photons emitted by the nuclear decay of a technetium-99 atom used in radiopharmaceuticals have an energy of 140.511 keV. Calculate the wavelength of these g-rays.

I'm not sure how to do this problem or what formulas to use; so far I converted the keV to Joules but I don't know what to do from here.

Tracy Tolentino_2E
Posts: 119
Joined: Sat Sep 07, 2019 12:17 am

### Re: 1B. 5

After converting to Joules, I used Planck's equation to find the frequency. From frequency, I used the speed of light equation to find wavelength.

Sartaj Bal 1J
Posts: 86
Joined: Thu Jul 25, 2019 12:17 am

### Re: 1B. 5

I combined the equations E equals Planck's constant times frequency and the speed of light equals wavelength times frequency to get wavelength equals Planck's constant times the speed of light all over energy. The energy is what you calculated in the first step converting keV to J. Hope this helps!

AGulati_4A
Posts: 74
Joined: Sat Sep 07, 2019 12:19 am

### Re: 1B. 5

Convert the value to Joules and then you can plug it in as a unit for Energy is the equation E=HV, where E is the energy, H is Planck's constant 9which will beon the formula sheet), and V is the wavelength -- which you can then find easily

VPatankar_2L
Posts: 89
Joined: Thu Jul 25, 2019 12:17 am
Been upvoted: 1 time

### Re: 1B. 5

You should convert the value of electron volts to Joules, and then write the equation of E=hv as E=(hc)/(wavelength). Then you can rewrite this equation as wavelength = (hc)/(E) and solve.