Passage I Short wavelength electromagnetic rays called X-rays are often used to
ID: 1788532 • Letter: P
Question
Passage I Short wavelength electromagnetic rays called X-rays are often used to image internal anatomical structures. Some parts of the body are nearly transparent to X-rays, while others are relatively opaque. A picture is taken of the shadow cast under X-ray illumination. The intensity of a beam of X-rays transmitted through a medium is given by where I, is the intensity incident on the medium, is the absorption coefficient of the medium (which is dependent upon the density of the medium), and x is the distance traveled through the medium. Like other electromagnetic waves, the frequency/and the wavelength of a beam of X-rays satisfy the relations c-M and E=hf where c is the speed of light in a vacuum, E is the energy of a photon, and h is Plank's constant. (Note: h = 6.62 x 10.34 m 3kg/s, 1 eV = 1.6 x 10-19 Joules.) X-rays interact with atoms primarily via collisions with electrons in low atomic energy levels. The probability of a collision with an electron in a neutral atom is proportional to the fourth power of the nuclear charge. In this type of collision, the electron is frequently ejected from the atom. A higher level electron falls down to fill the vacancy, emitting a long wavelength photon in the process and creating a new vacancy at a higher energy level. This process continues until there are no electrons at higher energy levels to fall to a lower state, leaving a single vacancy. The atom is then singly-ionized. This rapid emission of photons is called a cascade. Geiger counters measure the intensity of X-rays by maintaining a high voltage difference between a wire and the metal wall of a gas chamber. Free electrons created by radiation-induced ionization are accelerated toward the wire so rapidly they ionize even more atoms in the gas. This ionization avalanche causes the counter to clickExplanation / Answer
Answer is C
As given in the data we can say intersity is propsnal to negative power of e, when we take ratio opf it then negative power comes up and make ans e.