Answer:
c) Very dangerous and users must not override devices designed to protect from exposures.
Explanation:
X-ray is a form of high energy electromagnetic radiation and are part of the electromagnetic spectrum.
X-ray radiation from diffraction and fluorescence instruments is very dangerous because of their high energy and wavelength.
Hence, users must not override devices designed to protect from exposures. The best shielding device to protect one from exposure is Lead.
Question
What is the length of the pipe?
Answer:
(a) 0.52m
(b) f2=640 Hz and f3=960 Hz
(c) 352.9 Hz
Explanation:
For an open pipe, the velocity is given by

Making L the subject then

Where f is the frequency, L is the length, n is harmonic number, v is velocity
Substituting 1 for n, 320 Hz for f and 331 m/s for v then

(b)
The next two harmonics is given by
f2=2fi
f3=3fi
f2=3*320=640 Hz
f3=3*320=960 Hz
Alternatively,
and 

(c)
When v=367 m/s then

Answer:
It is used in MRI because it does not damage cells
Radio waves are used for space research because they have very long wavelengths
Explanation:
Many parts of the electromagnetic spectrum are applied in clinical diagnosis and treatment of illnesses. However, these highly ionizing radiation damage cells and its dosage must be carefully managed to avoid creating radiation related health problems for the patients.
Radio waves can be used in MRI without issues because the energy of the radiation is not sufficient to cause damage to cells but is sufficient to provide images for the sake of medical diagnosis.
Secondly, radio waves have long wavelength. This property is suitable for long range
communication. Hence it can be used in space research
Req = 30.0Ω.
When two or more resistors are in series, the intensity of current that passes through each of them is the same. Therefore, if you notice, you can observe that the three previous series resistors are equivalent to a single resistance whose value is the sum of each one.
Req = R1 + R2 + R3 = 10.0Ω + 10.0Ω + 10.0Ω = 30.0Ω
What diagram? There isn’t one