ok so heres the question:

Calculate the energy of a photon of electromagnetic radiation at each of the following frequencies.
For 100.7 MHz.
the equation to be used is E=Hc/lambda
H is planks constant: 6.626*10^ -34. andddd c is the speed of light: 3.0010^8.

the answer is 6.672×10−26 J.
but i got 1.974*10^ -21 and that's wrong. so i don't know what to plug in to get the correct answer.

1 answer

E = h*frequency (you can use hc/lambds but you must then convert 100.7 MHz to wavlength. Using h*f avoids this conversion).
E = 6.626E-34*100.7E6 = 6.672E-26
If you had shown your work I could have found the error.