# Engineering Physics Questions and Answers – Properties of X-Rays

This set of Engineering Physics Multiple Choice Questions & Answers (MCQs) focuses on “Properties of X-Rays”.

1. X-rays are weightless.
a) True
b) False

Explanation: X-rays are considered to be pure energy, no mass. They transfer energy from one point to another in the form of quanta/photon.

2. In free space, X-ray travels in ______________
a) Periodic oscillations
b) Non-Periodic oscillations
c) Zig-zag path
d) Straight line

Explanation: In free space, X-ray travels in a straight line. The X-ray moves with the speed of light (3 X 108 m/s) and is an electromagnetic wave.

3. X-Rays can be focused on to single point.
a) True
b) False

Explanation: X-rays cannot be focused onto a single point. They interact weakly with matter and the x-ray refractive index for most of the materials is very close to 1.0.

4. Fluorescence is the property when X-ray falls on a material it emits __________
a) Infrared Waves
b) Visible Light
c) Gamma rays
d) UV light

Explanation: When X-ray is incident on a specific material, it emits visible light. It happens because it excites the electron to a higher state which when jumps back to a lower state, releases photons. This property of X-ray is known as Fluorescence.

5. X-ray lies in which region of the electromagnetic spectrum?
a) 10 Å to 7000 Å
b) 4000 Å to 10 Å
c) 10 Å to 0.01 Å
d) 1 Å to 10 Å

Explanation: X-ray is an electromagnetic wave. It cannot be seen, smelt or heard. Its wavelength range is from 10 Å to 0.01 Å. Beyond X-rays lies Gamma rays.

6. The accelerating potential for an X-ray is 40 kV. What should be the minimum wavelength of the X-ray?
a) 0.024 nm
b) 0.031 nm
c) 0.097 nm
d) 0.054 nm

Explanation: We know, λmin = 1.24 X 10-6 Vm/ V
Here, V = 40 kV= 40000 V
Therefore, λmin = 1.24 X 10-6 Vm/ 40000 V
= 0.031 nm.

7. What is the effect of X-ray on methylene blue?
a) The crystal structure changes
b) It’s boiling point increases
c) It’s boiling point decreases
d) It gets bleached

Explanation: X-ray induces color change of many substances. When it is incident on Methyl orange, it causes methyl orange to get bleached. This is the chemical property of X-ray.

8. Which radical is generated in water by X-ray?
a) H2°
b) O2°
c) OH°
d) O°

Explanation: X-ray can be used to bring about a chemical change in a reaction as it can produce the highly active OH radical in water.

9. The following X-ray spectrum is for which material?

a) Tungsten
b) Molybdenum
c) Sodium
d) Uranium

Explanation: The following X-ray spectrum is for Molybdenum at 35 kV accelerating potential. Thus we can see that at a specific wavelength, a peak in the graph is observed.

10. The following figure shows a __________

a) X-ray scanner
b) X-ray tube
c) X-ray crystallographer
d) X-ray diffraction

Explanation: The given figure shows an X-ray tube. In this tube, X-rays are created by the collision of accelerating electron with a metal.

Sanfoundry Global Education & Learning Series – Engineering Physics.

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