Questions from Electronics


Q: Synchronized clocks are stationed at regular intervals, a million km apart

Synchronized clocks are stationed at regular intervals, a million km apart, along a straight line. When the clock next to you reads 12 noon: (a) What time do you see on the 90th clock down the line? (...

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Q: Compute the line integral of v = 6 xˆ + yz2

Compute the line integral of v = 6 xˆ + yz2 yˆ + (3y + z) zˆ along the triangular path shown in Fig. 1.49. Check your answer using Stokes’ theorem. [...

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Q: Prove that the symmetry (or antisymmetry) of a tensor is

Prove that the symmetry (or antisymmetry) of a tensor is preserved by Lorentz transformation (that is: if tμν is symmetric, show that t¯μν is also symmetric, and likewise for antisymmetric).

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Q: Recall that a covariant 4-vector is obtained from a contravariant

Recall that a covariant 4-vector is obtained from a contravariant one by changing the sign of the zeroth component. The same goes for tensors: When you “lower an indexâ€&#...

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Q: A straight wire along the z axis carries a charge density λ

A straight wire along the z axis carries a charge density λ traveling in the +z direction at speed v. Construct the field tensor and the dual tensor at the point (x , 0, 0).

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Q: Obtain the continuity equation (Eq. 12.126) directly

Obtain the continuity equation (Eq. 12.126) directly from Maxwell’s equations (Eq. 12.127).

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Q: Show that the second equation in Eq. 12.127 can

Show that the second equation in Eq. 12.127 can be expressed in terms of the field tensor Fμν as follows:

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Q: Work out, and interpret physically, the μ=0 component

Work out, and interpret physically, the μ=0 component of the electromagnetic force law, Eq. 12.128.

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Q: You may have noticed that the four-dimensional gradient operator ∂/∂

You may have noticed that the four-dimensional gradient operator ∂/∂xμ functions like a covariant 4-vector—in fact, it is often written ∂μ, for short. For instance, the continuity equation, ∂μ Jμ=0, h...

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Q: Show that the potential representation (Eq. 12.133)

Show that the potential representation (Eq. 12.133) automatically satisfies ∂Gμν /∂ xν = 0. [Suggestion: Use Prob. 12.54.]

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