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:

"Using the ramp decreases the amount of force needed to move the boxes, but the boxes must be moved over a longer distance" is the way among the following choices given in the question that a ramp <span>to load boxes into a truck make work easier. The correct option among all the options that are given in the question is option "D".</span>
The answer is A for sure , hope it’s correct
Answer: The clapper of an electric doorbell is an electromagnet. When the clapper of a doorbell strikes the bell, it opens an electric circuit. The electromagnet of an electric motor is connected to a permanent magnet. Only the shaft of an electric motor turns when current flows through the motor.
Explanation: hope this helped