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Electromagnetic Waves Class 12 Physics PYQs 2026-27 with Answers | Chapter 8
CBSE Class 12 Physics • Chapter 8 • 2026–27
Electromagnetic Waves Class 12 Physics PYQs with Answers
Previous-year question practice for CBSE Class 12 Physics Chapter 8, covering displacement current, conduction vs displacement current, EM-wave properties, E–B relationships, propagation direction, frequency/wavelength, the electromagnetic spectrum and elementary applications. Questions are presented in paraphrased form with year tags and concise solutions.
43 PYQ Records2019–2026 CoverageWith AnswersCBSE Board FocusChapter 8
Source discipline matters: CBSE's official question-paper archive is the authority for original board papers. This page uses published PYQ indexes and question-paper/marking-scheme reproductions to identify year/topic records, while presenting question wording in paraphrased form. Third-party chapter counts are used for discovery only and are not presented as official CBSE statistics.
Do not confuse PYQs with predictions: a past question does not guarantee repetition. Use PYQs to learn recurring concepts, command words, answer depth and common traps.
Quick Answer: What Should You Revise First?
Across the sourced PYQ material reviewed for this page, the recurring Chapter 8 areas include displacement current, transverse nature of EM waves, E–B relationships, electromagnetic-spectrum order and uses, frequency/wavelength reasoning, and applications of different spectrum regions. Recent PYQ indexes also show objective questions on field direction, wavelength/frequency and spectrum identification.
Current exam-design note: CBSE’s 2026–27 Physics framework allocates approximately 38% of theory marks to remembering/understanding, 32% to applying and 30% to analysing/evaluating/creating. That makes it useful to practise both direct recall and short reasoning/application questions rather than memorising only one question style.
| High-value area | What to be able to do |
|---|---|
| Displacement current | Define it, use Id = ε0dΦE/dt and explain continuity during capacitor charging. |
| EM-wave properties | State transverse nature, E ⟂ B ⟂ propagation, phase relation and vacuum propagation. |
| Field relation | Use E0/B0 = c and determine propagation direction from E × B. |
| Spectrum | Recall frequency/wavelength order and elementary uses of all seven regions. |
| Medium change | Know that frequency remains fixed at a boundary while speed and wavelength can change. |
Fresh PYQ Research Snapshot: 2019–2026
Recent cross-checking adds verified 2026 board-paper records and strengthens the pattern map around displacement current, field relationships, spectrum applications and short quantitative reasoning. The current official syllabus keeps Chapter 8 focused on displacement current, electromagnetic-wave characteristics, qualitative transverse nature and the seven-region spectrum with elementary uses.
Evidence labels: Official CBSE scope means the current 2026–27 curriculum. Verified PYQ record means a year/set/question record cross-checked against published paper or marking-scheme reproductions; the official CBSE archive remains the authority for the original paper. Search-intent/competitor research is used to improve coverage and wording, not to establish official CBSE statistics.
| Recent period | Recurring question patterns identified |
|---|---|
| 2026 | Verified records include spectrum applications (fractures, physiotherapy, radar, diagnosis, remote switches, water purification, heat waves, LASIK and cancer treatment), field geometry and free-space speed, microwaves, displacement current, conduction vs displacement current, E/B in glass and E–B phase relation. |
| 2025 | Photon momentum, field direction, spectrum comparisons, displacement current, characteristics of EM waves, radar/eye-surgery/medical-diagnosis applications and Assertion–Reason. |
| 2024 | Displacement current, capacitor continuity, spectrum applications, speed in a medium, field equations, wave orientation and interaction with matter. |
| 2023 and earlier | Propagation direction, E/B relationships, accelerated-charge production, spectrum identification, frequency/wavelength order, capacitor charging and medium-change reasoning. |
Interpretation: this is a research-based pattern summary, not a prediction or guarantee of future questions. Numerical wavelength ranges shown inside individual historical questions are retained only where the historical question itself asked for them; they should not be mistaken for fixed 2026–27 syllabus boundaries.
Chapter 8 Previous Year Questions
01
Electromagnetic spectrum
PYQ (paraphrased): Identify the radiation with the smallest wavelength from a set including visible, infrared, microwave and X-ray radiation.
Answer / solution: X-rays have the smallest wavelength among those options.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
02
Field-amplitude relation
PYQ (paraphrased): An EM wave in free space has magnetic-field amplitude 6.0 × 10⁻⁴ T. Determine the corresponding electric-field amplitude.
Answer / solution: Use E₀ = cB₀. Therefore E₀ = 3 × 10⁸ × 6.0 × 10⁻⁴ = 1.8 × 10⁵ V m⁻¹.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
03
Displacement current
PYQ (paraphrased): A parallel-plate capacitor has plate area 2.5 × 10⁻³ m² and the electric field changes at 4 × 10⁶ V m⁻¹ s⁻¹. Find the displacement current.
Answer / solution: I_d = ε₀ A(dE/dt) ≈ 8.85 × 10⁻⁸ A.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
04
Spectrum and uses
PYQ (paraphrased): Identify spectrum regions responsible for heating, ozone absorption and crystal-structure study, and give one production method for each.
Answer / solution: Infrared; ultraviolet; X-rays. Suitable production methods include thermal/vibrational emission for IR, electronic transitions/discharges for UV, and high-energy electron bombardment of a metal target for X-rays.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
05
Displacement current
PYQ (paraphrased): Define displacement current, distinguish it from conduction current, and explain why current remains continuous while a capacitor is charging.
Answer / solution: Displacement current is I_d = ε₀ dΦ_E/dt. Conduction current involves charge transport in a conductor; displacement current represents the changing electric-flux term. In the ideal capacitor gap, I_c = 0 while I_d equals the charging current.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
06
Wave fields
PYQ (paraphrased): For a plane EM wave travelling along +x with E along +y, identify the direction of B.
Answer / solution: B must be along +z so that E × B points along +x.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
07
Phase relation
PYQ (paraphrased): State the phase difference between E and B in a plane electromagnetic wave travelling along the z-axis.
Answer / solution: The phase difference is zero; E and B are in phase.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
08
Spectrum identification
PYQ (paraphrased): Identify the radiation having wavelength 10 nm.
Answer / solution: 10 nm lies in the X-ray region.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
09
Spectrum frequency
PYQ (paraphrased): Among infrared, gamma rays, radio waves and microwaves, identify the highest-frequency radiation.
Answer / solution: Gamma rays.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
10
Applications
PYQ (paraphrased): Identify the spectrum regions used for FM radio broadcasting, detecting bone fractures and treating muscular strain.
Answer / solution: Radio waves, X-rays and infrared radiation respectively.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
11
Field direction and uses
PYQ (paraphrased): For an EM wave travelling north with E oscillating vertically, determine B direction; compare radio/microwave wavelengths with visible light; state one use each of infrared and gamma radiation.
Answer / solution: B is perpendicular to both propagation and E, with direction fixed by E × B. Radio and microwave wavelengths are longer than visible light. Infrared is used in thermal sensing/heating; gamma rays have medical-treatment and sterilisation applications.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
12
Spectrum applications
PYQ (paraphrased): Name the EM radiation used in radar, a suitable eye-surgery application, and medical diagnosis, with the relevant wavelength-region idea.
Answer / solution: (i) Microwaves — approximately 10−3 to 1 m; (ii) ultraviolet radiation — approximately 10 to 400 nm; (iii) X-rays — approximately 0.01 to 10 nm. The exact band limits may vary by convention/source.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
13
Wave characteristics and displacement current
PYQ (paraphrased): State three characteristics of EM waves and explain how displacement current arises while a capacitor is charging.
Answer / solution: EM waves are transverse, E and B are mutually perpendicular and both are perpendicular to propagation, and they travel through vacuum. A changing electric flux in the capacitor gap gives displacement current.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
14
Photon momentum
PYQ (paraphrased): Among microwaves, TV/radio-type waves and X-rays, identify the radiation whose photons have the largest momentum.
Answer / solution: X-rays, because photon momentum p = h/λ and X-rays have the shortest wavelength among those choices.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
15
Assertion–Reason
PYQ (paraphrased): An Assertion–Reason item asked whether EM waves require a material medium and whether their transverse nature explains that fact.
Answer / solution: Assertion: true. Reason: true, but transverse nature alone is not the explanation for propagation through vacuum. Therefore the correct code is B.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
16
Production, field direction and spectrum comparison
PYQ (paraphrased): Explain how an electromagnetic wave is produced; determine the magnetic-field direction when the wave travels vertically upward and the electric field points west; and compare the shortest radio wavelength with the longest gamma-ray wavelength.
Answer / solution: EM radiation is associated with accelerated charges. Use E × B for the propagation direction: with propagation upward and E toward west, B must point north. For the spectrum, radio waves are at the longest-wavelength end whereas gamma rays are at the shortest-wavelength end, so the shortest radio wavelength is still much longer than the longest gamma-ray wavelength.
Source record: 2025 Set 55-2-2, cross-checked against a published question-paper/PYQ compilation. Wording is paraphrased; the official CBSE archive is the authority for the original paper and set.
17
Propagation direction
PYQ (paraphrased): Given E and B vectors of an electromagnetic wave, identify the propagation direction using a vector product.
Answer / solution: The propagation direction is along E × B.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
18
Frequency comparison
PYQ (paraphrased): Which has the highest frequency among visible light, infrared, microwaves and X-rays?
Answer / solution: X-rays.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
19
Production and characteristics
PYQ (paraphrased): Explain how electromagnetic waves are produced and state two characteristics.
Answer / solution: They are produced by accelerated charges. Two characteristics are their transverse nature and their ability to propagate through vacuum.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
20
Wave equation
PYQ (paraphrased): For an EM-wave expression of the form E_x = E₀ sin(kz − ωt), identify the quantities related to wavelength and frequency.
Answer / solution: Wavelength is related to k by λ = 2π/k; frequency is related to angular frequency by ν = ω/(2π).
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
21
Propagation in a medium
PYQ (paraphrased): State two medium properties that determine the velocity of light in that medium.
Answer / solution: The relevant electromagnetic response is described by the medium's permittivity and permeability.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
22
Spectrum wavelengths and uses
PYQ (paraphrased): Identify two EM regions from given wavelength intervals and state one use of each.
Answer / solution: The correct regions depend on the supplied wavelength intervals; identify them from the spectrum order and give a standard elementary use for each.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
23
Infrared / X-rays
PYQ (paraphrased): Explain production and uses of either infrared radiation or X-rays, depending on the paper's alternative.
Answer / solution: Infrared is associated with molecular/thermal motion and has heating and sensing uses; X-rays are produced using energetic electrons striking a target and are used in medical imaging and material analysis.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
24
Frequency in a medium
PYQ (paraphrased): For X-rays, red light and radio waves travelling through a medium, identify the physical quantity that remains unchanged.
Answer / solution: Frequency remains unchanged at a boundary when the radiation enters a new medium.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
25
UV radiation
PYQ (paraphrased): Identify the EM radiation responsible for sunburn and state its approximate wavelength region.
Answer / solution: Ultraviolet radiation; its wavelength lies roughly in the 10⁻⁸ to 10⁻⁷ m scale, with the exact range depending on the band specified.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
26
Variable-frequency capacitor
PYQ (paraphrased): A variable-frequency AC source charges a capacitor. Predict how displacement current changes when source frequency decreases.
Answer / solution: For the same voltage-amplitude conditions, displacement current decreases with frequency because the time rate of change of electric flux decreases.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
27
Field diagram
PYQ (paraphrased): Draw/describe the E and B field orientations for an EM wave travelling along +x with E along +y.
Answer / solution: B must be along +z so that E × B is +x.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
28
Microwaves
PYQ (paraphrased): Identify the spectrum region corresponding to a frequency range around 10¹⁰–10¹² Hz.
Answer / solution: Microwaves.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
29
Production of EM waves
PYQ (paraphrased): Explain briefly how electromagnetic waves are produced by an accelerating charge.
Answer / solution: An accelerating charge produces time-varying electric and magnetic fields that sustain one another and propagate outward as an EM wave.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
30
Charging capacitor
PYQ (paraphrased): Show that the displacement current between the plates of a charging parallel-plate capacitor equals the conduction current in the external circuit.
Answer / solution: For the ideal capacitor, I_d = ε₀ dΦ_E/dt. Using E = Q/(ε₀A) between the plates gives Φ_E = Q/ε₀ and hence I_d = dQ/dt = I_c.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
31
Displacement current equality
PYQ (paraphrased): A capacitor charging at 0.25 A is considered. Find the displacement current between its plates.
Answer / solution: For an ideal charging capacitor, I_d equals the charging/conduction current, so I_d = 0.25 A.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
32
Frequency order
PYQ (paraphrased): Arrange red light, X-rays, microwaves and radio waves in decreasing frequency.
Answer / solution: X-rays > red light > microwaves > radio waves.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
33
Refraction of UV
PYQ (paraphrased): How does the frequency of an ultraviolet beam change when it passes from air into glass?
Answer / solution: Its frequency remains unchanged; its speed and wavelength change.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
34
Infrared applications
PYQ (paraphrased): State applications of infrared radiation and identify an appropriate use involving thermal effects.
Answer / solution: Infrared is used in thermal sensing/imaging, remote controls and heating applications.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
35
Gamma-ray applications
PYQ (paraphrased): List important applications of gamma radiation.
Answer / solution: Applications include medical radiotherapy and sterilisation of suitable medical equipment/food under controlled conditions.
Source record: year/set information was cross-checked against published PYQ indexes or question-paper/marking-scheme reproductions. The wording above is paraphrased for student-facing presentation; consult the official CBSE archive for the original paper.
36
Spectrum applications: fractures, physiotherapy and radar
PYQ (paraphrased): Name the electromagnetic radiations used for detecting bone fractures, physiotherapy and radar systems, and state their approximate wavelength ranges.
Answer / solution: X-rays are used for bone-fracture imaging; infrared is used for physiotherapy/thermal treatment; microwaves are used in radar. Typical approximate ranges used in school-level references are X-rays ≈ 10−8–10−12 m, infrared ≈ 10−3–7 × 10−7 m, and microwaves ≈ 10−3–0.3 m. These ranges are approximate and are not separate 2026–27 syllabus boundaries.
Source record: 2026 Set 55-2-1, cross-checked against published question-paper/PYQ reproductions. Wording is paraphrased; the official CBSE archive is the authority for the original paper.
37
Spectrum applications: diagnosis, remote switches and water purification
PYQ (paraphrased): Identify the electromagnetic waves used as a diagnostic tool in medicine, in TV remote switches and in water purification, and give their approximate wavelength ranges.
Answer / solution: X-rays are used for medical diagnosis; infrared is used in TV remote controls; ultraviolet is used for water purification/disinfection. The question's wavelength-range requirement should be answered with the approximate ranges taught in the source material; remember that the current CBSE syllabus specifies the seven regions and elementary uses rather than fixed numerical boundaries.
Source record: 2026 Set 55-2-2, cross-checked against published question-paper/PYQ reproductions. Wording is paraphrased; the official CBSE archive is the authority for the original paper.
38
Heat waves, LASIK and cancer treatment
PYQ (paraphrased): Identify the electromagnetic radiation known as heat waves, the radiation used in LASIK eye surgery, and the radiation used to destroy cancer cells; state their wavelength ranges.
Answer / solution: Infrared is associated with heat waves; ultraviolet is used in suitable eye-surgery applications such as LASIK; gamma rays are used in cancer treatment. Treat the wavelength values as approximate spectrum-reference data, not as additional fixed syllabus limits.
Source record: 2026 Set 55-2-3, cross-checked against published question-paper/PYQ reproductions. Wording is paraphrased; the official CBSE archive is the authority for the original paper.
39
Field geometry and speed of electromagnetic waves
PYQ (paraphrased): Show the relative orientation of the electric field, magnetic field and direction of propagation of an electromagnetic wave; state two characteristics; and show that the free-space wave speed is 1/√(ε0μ0).
Answer / solution: For a plane EM wave, E ⟂ B and both are perpendicular to the propagation direction. Two valid characteristics are that EM waves are transverse in this qualitative plane-wave sense and can propagate through vacuum. In free space, c = 1/√(ε0μ0).
Source record: 2026 Set 55-3-1, cross-checked against published question-paper/PYQ reproductions. Wording is paraphrased; the official CBSE archive is the authority for the original paper.
40
Microwaves: definition, production and uses
PYQ (paraphrased): What are microwaves? State a suitable method of production and give two uses.
Answer / solution: Microwaves are electromagnetic waves between radio waves and infrared in the spectrum. They can be generated using devices such as a magnetron or klystron. Uses include radar and microwave heating; satellite communication is another standard application.
Source record: 2026 Set 55-4-2, cross-checked against published question-paper/PYQ reproductions. Wording is paraphrased; the official CBSE archive is the authority for the original paper.
41
Displacement current in a charging capacitor
PYQ (paraphrased): Define displacement current, obtain Id = ε0dΦE/dt for a charging capacitor, and state its value for a conductor across which a constant voltage is applied.
Answer / solution: Displacement current is the current-like term associated with changing electric flux: Id = ε0dΦE/dt. For an ideal charging capacitor, the changing electric field between the plates gives Id equal in magnitude to the conduction current in the external circuit. If the voltage across a conductor is constant, the electric field and flux are constant in the idealised situation, so Id = 0.
Source record: 2026 Set 55-5-1, cross-checked against published question-paper/PYQ reproductions. Wording is paraphrased; the official CBSE archive is the authority for the original paper.
42
Conduction current and displacement current
PYQ (paraphrased): Differentiate between conduction current and displacement current. For a capacitor connected to a time-dependent source, explain why the total current at an instant is represented by the conduction-current and displacement-current contributions.
Answer / solution: Conduction current is associated with actual charge transport through a conductor; displacement current is associated with changing electric flux. Maxwell's correction gives the current contribution as Itotal = Ic + Id. For an ideal charging capacitor, the gap contribution maintains continuity with the current in the connecting circuit.
Source record: 2026 Set 55-5-2, cross-checked against published question-paper/PYQ reproductions. Wording is paraphrased; the official CBSE archive is the authority for the original paper.
43
Phase relation of E and B
PYQ (paraphrased): An electromagnetic wave propagates along the x-axis. What is the phase difference between its electric and magnetic fields?
Answer / solution: The phase difference is zero. In a plane electromagnetic wave, E and B are spatially perpendicular but oscillate in phase.
Source record: 2026 Set 55-2-1, cross-checked against published question-paper/PYQ reproductions. Wording is paraphrased; the official CBSE archive is the authority for the original paper.
PYQ Revision Strategy: How to Use This Page
- First pass: Attempt the questions without notes. Mark every uncertain answer instead of checking immediately.
- Concept tagging: Group mistakes into displacement current, field geometry, E/B relations, spectrum and applications, and medium-change reasoning.
- Answer compression: For 1-mark questions, practise one precise line; for 2–3 mark questions, practise definition + reason/formula + conclusion.
- Numerical check: Rework the 2024/2025/2026 quantitative patterns using c = νλ, E₀/B₀, v = ω/k and Id = ε₀dΦE/dt.
- Final verification: Use the official CBSE archive for original papers and the current 2026–27 curriculum for scope; do not rely on third-party predictions.
Quick Answers: Electromagnetic Waves PYQs
What is displacement current?
It is the current-like quantity associated with changing electric flux: Id = ε0dΦE/dt.
It is the current-like quantity associated with changing electric flux: Id = ε0dΦE/dt.
What is the relation between E and B?
For a plane EM wave in vacuum, E0/B0 = c. In a medium, the ratio equals the wave speed v.
For a plane EM wave in vacuum, E0/B0 = c. In a medium, the ratio equals the wave speed v.
What is the order of the EM spectrum?
Radio → Microwave → Infrared → Visible → Ultraviolet → X-rays → Gamma, from lowest frequency to highest frequency.
Radio → Microwave → Infrared → Visible → Ultraviolet → X-rays → Gamma, from lowest frequency to highest frequency.
Does an EM wave need a medium?
No. Electromagnetic waves can propagate through vacuum.
No. Electromagnetic waves can propagate through vacuum.
Which EM wave has the highest frequency?
Gamma rays, among the seven regions listed in the current CBSE Class 12 syllabus.
Gamma rays, among the seven regions listed in the current CBSE Class 12 syllabus.
Which EM wave has the longest wavelength?
Radio waves, among the seven listed regions.
Radio waves, among the seven listed regions.
Frequently Asked Questions
Are these the exact original CBSE question-paper wordings?
No. The questions are deliberately paraphrased. This page preserves the year/topic/source information while avoiding reproduction of full copyrighted paper wording.
Which years are represented here?
The current set contains sourced records from 2019, 2020, 2023, 2024, 2025 and 2026. The official CBSE archive should be used when you need the original paper and set.
Which Chapter 8 PYQ topics recur most clearly?
Displacement current, EM-wave field relationships, transverse nature, spectrum order and uses, frequency/wavelength relationships and applications of specific radiation bands recur across the sources reviewed.
Does a PYQ guarantee repetition?
No. PYQs reveal past question patterns; they cannot guarantee the wording or topic of a future CBSE paper.
What was added in the latest 2026 PYQ research?
The page now includes 2026 patterns on displacement current, conduction versus displacement current, X-rays, microwaves, E/B in a medium, wave velocity, field geometry and phase relation.
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Explore the Study Pack →Scope, Source & Copyright Note
Research note: Recent cross-checking used the official CBSE archive for source authority and multiple secondary PYQ indexes/question-paper reproductions for discovery and year/topic verification. The page does not claim that any third-party database contains the complete official CBSE question set.
Sources, Verification & Search-Intent Research
- Official CBSE question-paper archive: authoritative destination for original Class XII papers. CBSE Previous Years' Question Papers
- Official CBSE 2026–27 curriculum: syllabus authority for current Chapter 8 scope. Physics 2026–27 Curriculum
- PYQ indexes and search-intent research: secondary resources such as PYQ Vault and chapter-wise PYQ compilations were used for discovery/corroboration only, not as substitutes for the official archive. Electromagnetic Waves PYQ index · Chapter 8 PYQ compilation
- Older questions are included only where their underlying concept remains relevant to the current Chapter 8 scope; students should still prioritise the current syllabus.
Editorial note: This page is a curated learning resource. Question statements are paraphrased rather than reproduced verbatim, while answers are written as concise study solutions. Year/set details are retained only where supported by the research record.
NCERT Physics Part-I: NCERT Physics Part-I PDF · Official Class XII 2026–27 SQP/MS: CBSE SQP & Marking Scheme
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