I would say D. because you round to the nearest whole number and 0.04 is way less than 0.5 which is a good rounding up number.
First electromagnet
Explanation:
The first electromagnet is the strongest and it is stronger than the given electromagnet above.
An electromagnet is a temporary magnet made by passing current through a wire wounded round an iron core or metallic core.
- When current is passed through, the metal becomes magnetic.
- The strength of the electromagnet depends on the number of coil round the metal core and also the intensity of current passed through it.
- The higher the number of coils wounded round the metal core, the stronger the electromagnet that will be produced.
- Also, the higher the intensity of electricity passed through the wire, the stronger it is.
learn more:
Electromagnet brainly.com/question/2191993
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A) 
The energy of an x-ray photon used for single dental x-rays is
The energy of a photon is related to its wavelength by the equation
where
is the Planck constant
is the speed of light
is the wavelength
Re-arranging the equation for the wavelength, we find
B) 
The energy of an x-ray photon used in microtomography is 2.5 times greater than the energy of the photon used in part A), so its energy is
And so, by using the same formula we used in part A), we can calculate the corresponding wavelength:
30 Grams would be your answer (I took the test and got it right)
