EM Spectrum MCQs for CBSE Board Exams
EM Spectrum MCQs for CBSE Board Exams
Class: 12 | Subject: Physics
Section: 5 – Electromagnetic Waves
Topic: EM Spectrum MCQs
Based on: CBSE Board Examination Pattern
Section: 5 – Electromagnetic Waves
Topic: EM Spectrum MCQs
Based on: CBSE Board Examination Pattern
Instructions: These Multiple Choice Questions (MCQs) are designed strictly as per the NCERT syllabus, making them ideal for CBSE Class 12 Board Examination preparation.
1. The electromagnetic spectrum is arranged according to:
Answer: B
EM spectrum is ordered by increasing wavelength or decreasing frequency.
EM spectrum is ordered by increasing wavelength or decreasing frequency.
2. Which has the longest wavelength?
Answer: A
Radio waves occupy the lowest frequency and longest wavelength region.
Radio waves occupy the lowest frequency and longest wavelength region.
3. Which has the shortest wavelength?
Answer: C
Gamma rays are most energetic with shortest wavelength.
Gamma rays are most energetic with shortest wavelength.
4. Visible spectrum range is:
Answer: A
From violet (~400 nm) to red (~700 nm).
From violet (~400 nm) to red (~700 nm).
5. Infrared radiation is mainly associated with:
Answer: A
IR is emitted by hot bodies → thermal radiation.
IR is emitted by hot bodies → thermal radiation.
6. Microwaves are used in radar because they:
Answer: B
They travel long distances with minimal absorption.
They travel long distances with minimal absorption.
7. UV rays can cause:
Answer: A
High energy damages skin cells.
High energy damages skin cells.
8. X-rays are used in:
Answer: C
They penetrate soft tissue.
They penetrate soft tissue.
9. Gamma rays originate from:
Answer: B
Produced in radioactive decay.
Produced in radioactive decay.
10. Order of increasing frequency:
Answer: A
Standard EM spectrum order.
Standard EM spectrum order.
11. Energy of radiation depends on:
Answer: A
E = hν.
E = hν.
12. Radio waves are produced by:
Answer: C
In transmitting antennas.
In transmitting antennas.
13. Infrared is detected using:
Answer: A
Measures heat radiation.
Measures heat radiation.
14. UV sterilizes because it:
Answer: B
Kills bacteria by DNA damage.
Kills bacteria by DNA damage.
15. Visible light is detected by:
Answer: B
Human eye photoreceptors.
Human eye photoreceptors.
16. Highest penetrating power:
Answer: C
Very high energy photons.
Very high energy photons.
17. Heating effect maximum in:
Answer: A
Absorbed as thermal energy.
Absorbed as thermal energy.
18. EM waves travel fastest in:
Answer: C
Speed = c.
Speed = c.
19. Communication satellites use:
Answer: C
Low atmospheric attenuation.
Low atmospheric attenuation.
20. EM spectrum was unified by:
Answer: B
Electromagnetic theory of light.
Electromagnetic theory of light.