The electric field associated with an e.m. wave in vacuum is given by
The electric field associated with an e.m. wave in vacuum is given by E = i 40 cos (kz – 6 x 10⁸ t), where E, z and t are in volt/m, meter and seconds […]
Questions
The decreasing order of wavelength of infrared, microwave, ultraviolet and gamma
The decreasing order of wavelength of infrared, microwave, ultraviolet and gamma rays is
Options
(a) microwave, infrared, ultraviolet, gamma rays (b) gamma rays, ultraviolet, infrared, microwaves (c) microwaves, gamma rays, infrared, ultraviolet (d) […]
The electric and magnetic field assiciated with an E.M. wave
The electric and magnetic field associated with an E.M. wave, propagating along the +z axis, can be represented by
Options
(a) [ E = E₀i, B = B₀j ] (b) [E = E₀k, […]
which of the following statement is false for the properties of electromagnetic waves?
which of the following statement is false for the properties of electromagnetic waves?
Options
(a) Both electric and magnetic field vectors attain the maxima and minima at the same place and same time. […]
The electric field part of an electromagnetic wave in a medium is represented by
The electric field part of an electromagnetic wave in a medium is represented by Ex = 0 Ey = 2.5 (N / C) cos [(2π x 10⁶ rad/m) t – (π x 10⁻² rad/s) x […]
If c is the velocity of light in free space, the time taken by light to travel
If c is the velocity of light in free space, the time taken by light to travel a distance x in a medium refractive index μ is
Options
(a) x/c (b) μx/c (c) […]
The velocity of electromagnetic radiation in a medium of permittivity ε₀
The velocity of electromagnetic radiation in a medium of permittivity ε₀ and permeability μ₀ is given by
Options
(a) √(ε₀ / μ₀) (b) √(μ₀ ε₀) (c) 1 / √(μ₀ ε₀) (d) √(μ₀ / ε₀)
The condition under which a microwave oven heats up a food item containing
The condition under which a microwave oven heats up a food item containing water molecules most efficiently is
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(a) the frequency of the microwave must match the resonant frequency of the water […]
The electromagnetic waves detected using a thermopile and used in physical therapy
The electromagnetic waves detected using a thermopile and used in physical therapy are
Options
(a) gamma radiations (b) x-rays (c) ultraviolet radiations (d) infrared radiations
Correct Answer:
infrared radiations
Explanation:
The electromagnetic waves […]
In electromagnetic spectrum, the frequencies of γ-rays and x-rays and ultraviolet rays
In electromagnetic spectrum, the frequencies of γ-rays and x-rays and ultraviolet rays are denoted by n₁,n₂ and n₃ respectively, then
Options
(a) n₁>n₂>n₃ (b) n₁n₃
Explanation:
Frequency range of ultraviolet rays ≃ 10¹⁶ […]