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Help photons physics question

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I think it is C my working:
The change in energy is 4.08x10^-19
I then equated it to hc / λ
Rearranged to get λ = 4.875x10^-7 m
Is this wrong?
That looks correct to me
Original post by wizkid44
That looks correct to me

Oh I see. It's just that I thought since it's in nano meters it has be 10^-9 ???
Original post by beatricehalley
Oh I see. It's just that I thought since it's in nano meters it has be 10^-9 ???


Since the number you got is 10 to the power of -7, to convert to 10 to the power of -9, you have to multiply the base by 10 to the power of 2.

It’s a bit hard to explain in writing
Original post by wizkid44
Since the number you got is 10 to the power of -7, to convert to 10 to the power of -9, you have to multiply the base by 10 to the power of 2.

It’s a bit hard to explain in writing

Oh so it's still right it's just they converted it in nano meters huh
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Sinnoh
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Original post by beatricehalley
Oh I see. It's just that I thought since it's in nano meters it has be 10^-9 ???


It's in hundreds of nanometres. You could rewrite it as 487.5*10^-9, and that would make it obvious what the wavelength was in nanometres, but it's unnecessary. The more you practise it the more you'll get used to the kinds of powers of ten and what they correspond to.
Original post by beatricehalley
Oh so it's still right it's just they converted it in nano meters huh


yeah
There's several ways of writing the exact same number in scientific notation...

Fwiw I think about it as jumping the decimal point 2 places to the right and subtracting 2 from the exponent, same number just a more convinient way of writing it down.

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