The intrinsic impedance of free space isa)489b)265c)192d)377Correct an...
Answer: d
Explanation: The intrinsic impedance is the square root of ratio of the permeability to the permittivity. In free space, the permeability and the permittivity is same as the absolute permeability and permittivity respectively. This is due to unity permeability and permittivity in free space. Thus η = √(μ/ε), where absolute permeability is given by 4π x 10-7 and absolute permittivity is given by 8.854 x 10-12. The intrinsic impedance will be 377 ohms.
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The intrinsic impedance of free space isa)489b)265c)192d)377Correct an...
The intrinsic impedance of free space is defined as the ratio of the electric field to the magnetic field in an electromagnetic wave propagating through empty space. It is denoted by the symbol 'Z0' and has a value of approximately 377 ohms.
Explanation:
1. Definition of intrinsic impedance:
- The intrinsic impedance of a medium is a characteristic property that relates the electric and magnetic fields in an electromagnetic wave propagating through that medium.
- It is defined as the ratio of the magnitude of the electric field (E) to the magnitude of the magnetic field (H).
- Mathematically, it can be expressed as Z0 = E/H.
2. Intrinsic impedance of free space:
- Free space refers to the absence of any medium or material.
- In free space, electromagnetic waves propagate without any obstacles or interactions with matter.
- The intrinsic impedance of free space, denoted as Z0, is a fundamental constant in electromagnetics.
- Its value is approximately 377 ohms (Ω), which is a consequence of the relationship between the speed of light and the permeability and permittivity of free space.
3. Relationship with other constants:
- The intrinsic impedance of free space is related to the speed of light (c), the vacuum permeability (μ0), and the vacuum permittivity (ε0).
- It can be expressed as Z0 = sqrt(μ0/ε0), where μ0 = 4π×10^-7 H/m and ε0 = 8.854×10^-12 F/m.
- Plugging in the values, Z0 = sqrt((4π×10^-7 H/m)/(8.854×10^-12 F/m)) ≈ 377 Ω.
4. Importance in transmission lines and waveguides:
- The intrinsic impedance of free space serves as a reference point for the characteristic impedance of transmission lines and waveguides.
- Transmission lines and waveguides are designed to match the impedance of the source and load for efficient power transfer.
- The characteristic impedance of a transmission line is often chosen to be equal to the intrinsic impedance of free space to minimize reflections and maximize power transfer.
In conclusion, the intrinsic impedance of free space, denoted as Z0, is a fundamental constant in electromagnetics with a value of approximately 377 ohms. It is a property that relates the electric and magnetic fields in an electromagnetic wave propagating through empty space.
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