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Electromagnetic Waves

Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.

Displacement Current

Subtopic

Displacement Current under Electromagnetic Waves for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Displacement current exists only when:

    A.

    The electric field is constant

    B.

    The magnetic field is constant

    C.

    The electric flux is changing with time

    D.

    The circuit is in a steady state

  2. 2.

    Consider a parallel plate capacitor being charged by a DC source. During the charging process, where does the displacement current exist?

    A.

    Only in the connecting wires

    B.

    Only in the space between the capacitor plates

    C.

    Both in the wires and between the plates

    D.

    Neither in the wires nor between the plates

  3. 3.

    The displacement current IdI_d is mathematically expressed as:

    A.

    Id=ϵ0dΦEdtI_d = \epsilon_0 \frac{d\Phi_E}{dt}

    B.

    Id=1ϵ0dΦEdtI_d = \frac{1}{\epsilon_0} \frac{d\Phi_E}{dt}

    C.

    Id=μ0dΦBdtI_d = \mu_0 \frac{d\Phi_B}{dt}

    D.

    Id=ϵ0dEdtI_d = \epsilon_0 \frac{dE}{dt}

Download the worksheet for Electromagnetic Waves - Displacement Current to practice offline. It includes additional chapter-level practice questions.

Electromagnetic Spectrum

Subtopic

Electromagnetic Spectrum under Electromagnetic Waves for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    The 'Greenhouse effect', which keeps the Earth's atmosphere warm, is primarily due to the absorption and re-radiation of which type of electromagnetic waves?

    A.

    Ultraviolet rays

    B.

    Cosmic rays

    C.

    X-rays

    D.

    Infrared rays

  2. 2.

    What is the ratio of the speed of Gamma rays to the speed of Radio waves in a vacuum?

    A.

    1:11:1

    B.

    1010:110^{10}:1

    C.

    1:10151:10^{15}

    D.

    2:12:1

  3. 3.

    Which of the following electromagnetic waves has the shortest wavelength?

    A.

    Visible light

    B.

    Gamma rays

    C.

    X-rays

    D.

    Radio waves

Download the worksheet for Electromagnetic Waves - Electromagnetic Spectrum to practice offline. It includes additional chapter-level practice questions.

Properties of EM Waves

Subtopic

Properties of EM Waves under Electromagnetic Waves for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    The transverse nature of electromagnetic waves is experimentally demonstrated by which phenomenon?

    A.

    Interference

    B.

    Diffraction

    C.

    Refraction

    D.

    Polarization

  2. 2.

    Electromagnetic waves are produced by charges that are:

    A.

    At rest

    B.

    Moving with a uniform velocity

    C.

    Accelerating

    D.

    Moving in a straight line with constant speed

  3. 3.

    The peak value of the electric field (E0E_0) and the magnetic field (B0B_0) of an electromagnetic wave in vacuum are related by the equation:

    A.

    E0=B0/cE_0 = B_0 / c

    B.

    B0=E0/cB_0 = E_0 / c

    C.

    E0B0=cE_0 B_0 = c

    D.

    E0=B0/cE_0 = \sqrt{B_0 / c}

Download the worksheet for Electromagnetic Waves - Properties of EM Waves to practice offline. It includes additional chapter-level practice questions.

Electromagnetic Waves - Class 12 Physics (CBSE) | Krit.club