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Class 12 Electromagnetic Waves worksheet
CBSE Physics. Displacement current, c = fλ, E₀/B₀ = c, the electromagnetic spectrum and its uses. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
The wavelength of an electromagnetic wave of frequency 1 × 10¹¹ Hz in vacuum is:
- 3 × 10⁻⁴ m
- 3 × 10¹⁹ m
- 0.03 m
- 3 × 10⁻³ m
Answer
(d) 3 × 10⁻³ m
λ = c/f
- 2.
The electric field of an electromagnetic wave has amplitude 222 V/m. The amplitude of its magnetic field is:
- 7.4 × 10⁻⁷ T
- 6.66 × 10¹⁰ T
- 7.4 × 10⁻⁵ T
- 7.4 × 10⁻⁹ T
Answer
(a) 7.4 × 10⁻⁷ T
B₀ = E₀/c
- 3.
Electromagnetic radiation of wavelength 450 nm is:
- microwaves
- radio waves
- gamma rays
- visible light
Answer
(d) visible light
visible light: 400 nm to 700 nm
Section B · short answer
- 4.
A radio station broadcasts at 102 MHz. Find the wavelength of its waves.
Answer
2.94 m
λ = c/f = 3 × 10⁸ ÷ (102 × 10⁶)
- 5.
The magnetic field of a plane electromagnetic wave has amplitude 30 × 10⁻⁸ T. Find the amplitude of its electric field.
Answer
90 V/m
E₀ = cB₀
Section C · long answer
- 6.
A plane electromagnetic wave of frequency 5 × 10¹² Hz travels along x in vacuum, and its electric field amplitude is 51 V/m. Find its wavelength, its angular frequency, the amplitude of its magnetic field, and the direction of B if E is along y.
Answer
6 × 10⁻⁵ m; 1 × 10¹³π rad/s; 1.7 × 10⁻⁷ T; along z
λ = c/f; ω = 2πf; B₀ = E₀/c; E × B points along the direction of travel
Fresh sheets for your child
In the app, every Electromagnetic Waves sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
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