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The threshold frequency for certain metals is v0​. When the light of frequency 2v0​ is incident on it, the maximum velocity of photoelectrons is 4×106ms−1. If the frequency of incident radiation is increased to 5v0, then the maximum velocity of photoelectrons will be : (A) 2 × 106 ms−1(B) 2 × 107 ms−1 (C) 4/5 × 106 ms−1 (D) 8 × 106 ms−1

The Einstein's equation for photoelectric effect is given by, where KE= maximum kinetic energy of electron h= Planck's constant =... View Article

A small town with a demand of 800 kw of electric power at 220 v is situated 15 km away from an electric plant generating power at 440 v.the resistance of the two-wire line carrying power is 0.5 ωper km. The town gets power from the line through a 4000-220 v step-down transformer at a sub-station in the town.(a) Estimate the line power loss in the form of heat. (b) How much power must the plant supply, assuming there is negligible power loss due to leakage? (c) Characterise the step up transformer at the plant.

Given: Supply voltage, V = 220 V Total electric power required, P = 800 kW = The voltage at which the electric plant is generating power, V'... View Article

Two discs of moments of Inertia I1 and I2 about their respective axes (normal to the disc and. passing through the centre), and rotating with angular speeds ω1, and ω2 are brought Into contact face to face with their axes of rotation coincident. (A) What is the angular speed of the two-disc system? (B) Show that the kinetic energy of the combined system is less than the sum of the initial kinetic energies of the two discs. How do you account for this loss In energy? Take ω1 ≠ ω2.

(A) What is the angular speed of the two-disc system? The monent of inertia of disc The angular speed of disc I = The angular speed of disc... View Article