Electromagnetic SpectrumCopy
1. Which electromagnetic wave has the greatest photon energy?
A) Microwave
B) Infrared
C) Gamma ray
D) X-ray
2. Which wave in the electromagnetic spectrum is used to treat cancer?
A) Radio wave
B) Gamma ray
C) Microwave
D) Infrared
3. All electromagnetic waves:
A) Require a medium to propagate
B) Are longitudinal
C) Travel at the same speed in vacuum
D) Have the same frequency in all media
4. Which type of electromagnetic radiation is absorbed by bones and used for imaging?
A) Ultraviolet
B) X-rays
C) Infrared
D) Radio waves
5. Which of the following best explains why gamma rays are more harmful than radio waves?
A) They travel faster
B) They have higher energy
C) They are longitudinal
D) They have longer wavelengths
6. The speed of all electromagnetic waves in vacuum is:
A) 3 × 10⁸ m/s
B) 3 × 10⁶ m/s
C) Variable depending on wavelength
D) Less than sound waves in air
7. Which wave is used in satellite communication?
A) X-rays
B) Microwaves
C) Infrared
D) Ultraviolet
8. Which wave has the longest wavelength?
A) X-rays
B) Gamma rays
C) Radio waves
D) Ultraviolet
9. Which electromagnetic radiation causes skin tanning?
A) Infrared
B) Ultraviolet
C) Microwaves
D) Visible light
10. Which wave type is used in remote control devices?
A) Gamma rays
B) X-rays
C) Infrared
D) Visible light
11. Which type of radiation is used to kill bacteria in water treatment?
A) Infrared
B) Ultraviolet
C) Radio waves
D) Microwaves
12. Which of the following is used in Bluetooth and short-range communication?
A) Microwaves
B) X-rays
C) Gamma rays
D) Infrared
13. The correct order of electromagnetic waves from lowest to highest frequency is:
A) Gamma, X-ray, UV, visible, IR, microwave, radio
B) Radio, microwave, IR, visible, UV, X-ray, gamma
C) Microwave, radio, visible, IR, X-ray, UV, gamma
D) UV, IR, visible, radio, gamma, microwave, X-ray
14. Which property increases with increasing frequency?
A) Wavelength
B) Penetrating power
C) Reflection
D) Diffraction
15. Which radiation type causes internal heating in human tissues?
A) Ultraviolet
B) Microwaves
C) Gamma rays
D) X-rays
16. Visible light lies between:
A) X-rays and gamma rays
B) Infrared and ultraviolet
C) Microwave and gamma rays
D) Radio waves and X-rays
17. Which of the following is not a common property of electromagnetic waves?
A) They are all transverse
B) They all carry charge
C) They travel at same speed in vacuum
D) They can be reflected and refracted
18. Infrared radiation is detected mainly due to its:
A) Fluorescent effect
B) Penetration ability
C) Heating effect
D) Magnetic field
19. Which radiation is most responsible for damage to DNA?
A) Infrared
B) Ultraviolet
C) Radio waves
D) Microwaves
20. The wavelength of red light is approximately:
A) 0.4 µm
B) 0.6 µm
C) 0.1 µm
D) 1.0 µm
21. Which waves are used in airport security scanners?
A) Infrared
B) Gamma rays
C) X-rays
D) UV rays
22. Which wave is emitted by radioactive substances?
A) X-rays
B) Gamma rays
C) Infrared
D) Microwave
23. What is the primary source of ultraviolet radiation?
A) Earth’s core
B) Sun
C) Satellites
D) Optical fibres
24. What is the correct expression for speed of electromagnetic waves?
A) v = fλ
B) v = λ/f
C) f = λ/v
D) v = f + λ
25. Which radiation is absorbed by the ionosphere?
A) Shortwave radio
B) Gamma rays
C) Microwaves
D) Visible light
26. Why are X-ray machines shielded with lead?
A) To reflect radiation
B) To absorb high-frequency waves
C) To generate more X-rays
D) To reduce resolution
27. Which radiation is used in thermal imaging?
A) Microwaves
B) Ultraviolet
C) Infrared
D) Gamma rays
28. Which part of the EM spectrum is mostly responsible for burns from hot objects?
A) Microwaves
B) Gamma rays
C) Infrared
D) Ultraviolet
29. Which radiation causes fluorescence in materials?
A) X-rays
B) Gamma rays
C) Ultraviolet
D) Visible light
30. The wave with highest frequency among these is:
A) X-rays
B) UV
C) Gamma rays
D) Visible light
31. Which radiation travels fastest in glass?
A) Violet
B) Red
C) Infrared
D) They all travel at same speed
32. Which radiation is best suited for sterilising surgical instruments?
A) Microwave
B) Infrared
C) Gamma rays
D) Visible light
33. Which of the following statements is correct?
A) EM waves are mechanical
B) EM waves are longitudinal
C) EM waves cannot travel in vacuum
D) EM waves have electric and magnetic fields
34. Which property is common to all electromagnetic waves?
A) Polarisation
B) Being longitudinal
C) Carrying energy
D) Changing frequency in a vacuum
35. The energy of a photon is:
A) Proportional to its amplitude
B) Inversely proportional to its speed
C) Proportional to frequency
D) Inversely proportional to wavelength
1. ✅ C) Gamma ray
Highest frequency = highest energy (E=hf)(E = hf)
❌ A/B/D – Lower frequencies
2. ✅ B) Gamma ray
Used in radiotherapy to kill cancer cells
❌ A/C/D – Too low energy
3. ✅ C) Travel at the same speed in vacuum
All EM waves = 3×1083 times 10^8 m/s in vacuum
❌ A – No medium needed
❌ B – All are transverse
❌ D – Frequency depends on source, not medium
4. ✅ B) X-rays
Penetrate soft tissue but absorbed by bone
❌ A – UV has lower penetration
❌ C/D – Don’t image bones
5. ✅ B) They have higher energy
Shorter wavelength = more energy
❌ A – All travel same speed
❌ C – EM waves are transverse
❌ D – Gamma has shorter λ
6. ✅ A) 3 × 10⁸ m/s
Universal speed in vacuum
❌ B – Too slow
❌ C – Speed is constant
❌ D – False, EM > sound speed
7. ✅ B) Microwaves
Used in satellite and mobile comms
❌ A – Too energetic
❌ C/D – Less efficient over long distance
8. ✅ C) Radio waves
Longest λ and lowest frequency
❌ A/B/D – Shorter wavelengths
9. ✅ B) Ultraviolet
UV triggers melanin production = tanning
❌ A – Heats but no tanning
❌ C – No biological effect
❌ D – Safe visible light
10. ✅ C) Infrared
Used in TV remotes
❌ A/B – Too harmful
❌ D – Needs direct line of sight
11. ✅ B) Ultraviolet
Kills microorganisms
❌ A – Only heats
❌ C/D – Too low energy
12. ✅ D) Infrared
Used in short-range data transfer
❌ A – Used in long-range
❌ B/C – Harmful
13. ✅ B) Radio, microwave, IR, visible, UV, X-ray, gamma
Standard increasing frequency order
❌ Others – Incorrect sequence
14. ✅ B) Penetrating power
Higher frequency → more energy → more penetration
❌ A – Wavelength decreases
❌ C – Reflection not directly linked
❌ D – Diffraction better at longer wavelengths
15. ✅ B) Microwaves
Cause water molecule vibrations → heat
❌ A – Surface damage
❌ C/D – High energy but not internal heating
16. ✅ B) Infrared and ultraviolet
Visible spectrum lies in between
❌ A/C/D – Incorrect positioning
17. ✅ B) They all carry charge
False – EM waves don’t carry charge
✅ Others – All correct properties
18. ✅ C) Heating effect
Infrared radiation = heat radiation
❌ A – UV causes fluorescence
❌ B – Not penetrating
❌ D – Not detectable basis
19. ✅ B) Ultraviolet
Can break DNA bonds – mutagenic
❌ A/C/D – Not harmful enough
20. ✅ B) 0.6 µm
Red light ≈ 600 nm = 0.6 µm
❌ A – Blue/violet
❌ C – Too small
❌ D – Too large
21. ✅ C) X-rays
Used to scan bags/body
❌ A – Detect heat
❌ B – Too harmful
❌ D – Weak penetration
22. ✅ B) Gamma rays
Released from radioactive decay
❌ A – Produced artificially
❌ C/D – No connection to radioactivity
23. ✅ B) Sun
Natural UV source
❌ A/C/D – Not major UV sources
24. ✅ A) v = fλ
Universal wave equation
❌ Others – Incorrect formulas
25. ✅ A) Shortwave radio
Absorbed/reflected by ionosphere for long distance comm
❌ B – Absorbed by upper atmosphere
❌ C/D – Not significantly affected
26. ✅ B) To absorb high-frequency waves
Lead shields block harmful X-rays
❌ A – Doesn’t reflect
❌ C – Not for generation
❌ D – Irrelevant
27. ✅ C) Infrared
Thermal cameras detect heat → IR
❌ A – Wrong region
❌ B – Non-thermal
❌ D – Too high energy
28. ✅ C) Infrared
Hot objects emit IR → skin burns
❌ A – Not main burn cause
❌ B/D – Not heat-related
29. ✅ C) Ultraviolet
UV causes fluorescence in some materials
❌ A/B – Ionizing but not fluorescent
❌ D – May reflect, but not cause fluorescence
30. ✅ C) Gamma rays
Highest frequency in EM spectrum
❌ A/B/D – Lower
31. ✅ B) Red
Lower refractive index → faster in glass
❌ A/C – Slower due to higher refraction
❌ D – Incorrect; speed varies
32. ✅ C) Gamma rays
Sterilisation via ionizing damage
❌ A – Heating only
❌ B – External heating
❌ D – Not sterilising
33. ✅ D) EM waves have electric and magnetic fields
Definition of EM waves
❌ A/B/C – False characteristics
34. ✅ C) Carrying energy
All EM waves transport energy
❌ A – Not all are polarised
❌ B – All are transverse
❌ D – Frequency fixed in vacuum
35. ✅ C) Proportional to frequency
E = hf
❌ A – Amplitude doesn’t affect energy
❌ B – Speed is constant
❌ D – Inversely proportional to wavelength, but that’s indirect