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Compute the typical de Broglie wavelength of an electron in a metal at 27 °C and compare it with the mean separation between two electrons in a metal which is given to be about 2 × 10–10 m. [Note: Exercises 35 and 36 reveal that while the wave-packets associated with gaseous molecules under ordinary conditions are non-overlapping, the electron wave-packets in a metal strongly overlap with one another. This suggests that whereas molecules in an ordinary gas can be distinguished apart, electrons in a metal cannot be distintguished apart from one another. This indistinguishibility has many fundamental implications which you

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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An electromagnetic wave of wavelength λ is incident on a photosensitive surface of negligible work function. If the photoelectrons emitted form this surface have de-broglie wavelength `λ_1` . Prove that

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Calculate the threshold frequency of photon for photoelectric emission from a metal of work function

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Why are de – broglie waves associated with a moving football is not

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A free proton and a free electron are placed in a uniform field. Which of the two experience greater force and greater

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No two electric lines of force can intersect each other?

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The graph shows the variation of voltage V across the plates of two capacitors A and B versus increase of charge Q stored on them. Which of the two capacitors have higher capacitance? Give reason for your answer?

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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The diagram shows a uniformly charged hemisphere of radius R. It has volume charge density `rho`. If the electric field at a point 2R distance above its centre is E then what is the electric field at the point which is 2R below its

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A metallic rod of length `l` rotates at angular velocity `omega` about an axis passing through one end and perpendiuclar to the rod. If mass of electron is m and its charge is –e then the magnitude of potential difference between its two ends

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What is the angular acceleration of the rod at the instant of releasing the rod? A thin homogeneous rod of mass m and length `l` is free to rotate in vertical plane about a horizontal axle pivoted at one end of the rod. A small ball of mass m and charge q is attached to the opposite end of this rod. The whole system is positioned in a constant horizontal electric field of magnitude mg `E=(mg)/(2q)`. The rod is released from shown position from

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Two point charges repel each other with a force of 100 N. One of the charges is increased by 10% and other is reduced by 10%. The new force of repulsion at the same distance would be ........

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Consider a uniform electric field E = 3 × 103 î N/C. What is the flux through the same square if the normal to its plane makes a 60° angle with the

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Careful measurement of the electric field at the surface of a black box indicates that the net outward flux through the surface of the box is 8.0 × 103 `Nm^2`/C. What is the net charge inside the box?Why or Why

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A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density of 80.0 µC/m2 . What is the total electric flux leaving the surface of the

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Which among the curves shown in Fig. cannot possibly represent electrostatic field lines?

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Five charges q1, q2, q3, q4, and q5 are fixed at their positions as shown in Fig. S is a Gaussian surface. The Gauss’s law is given by`oint_0^1 vec E cdot vec (ds)=q/epsilon_0` Which of the following statements is correct?

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Fig. shows the electric field lines around three point charges A, B and C. In which region or regions of the picture could the electric field be zero? Justify your answer. (i) near A, (ii) near B, (iii) near C, (iv)

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To reduce the reasonant frequency in an LCR series circuit with a

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How does the sign of the phase angle φ, by which the supply voltage leads the current in an LCR series circuit, change as the supply frequency is gradually increased from very low to very high

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An electrical device draws 2kW power from AC mains (voltage223V (rms) = `sqrt50,000` V).The current differs (lags) in phase by `φ tan φ=-3/4` as compared to voltage. Find I M. Another device has twice the values for R, XC and XL. How are the answers

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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