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### Daily Question Banks for Engineering Entrance and Board Exams

Questions
 Physics Two metallic plates A and B, each of area 5x10-4 m2, are placed parallel to each other at a separation of 1 cm. Plate B carries a positive charge of 33.7x10-12C. A monochromatic beam of light, with photons of energy 5eV each, starts falling on plate A at t = 0 so that 1016 photons fall on it per square meter per second. Assume that one photoelectron is emitted for every 106 incident photons. Also assume that all the emitted photoelectrons are collected by plate B and the work function of plate A remains constant at the value 2eV. Determine (a) the number of photoelectrons emitted up to t = 10sec (b) the magnitude of the electric field between the plates A and B at t = 10sec, and (c) the kinetic energy of the most energetic photoelectron emitted at t =10sec when it reaches plate B. Neglect the time taken by the photoelectron to reach plate B. Take Chemistry Which species has the maximum number of lone pair of electrons on the central atom? (a) [CIO3]- (b) XeF4 (c) SF4 (d) [I3]- Mathematics The vertex of a parabola is the point (a, b) and latus rectum is of length l. If the axis of the parabola is along the positive direction of y-axis, then its equation is (a) (x + a)2 = l/2 (2y – 2b) (b) (x – a)2 = l/2 (2y – 2b) (c) (x + a)2 = l/4 (2y – 2b) (d) (x – a)2 = l/8 (2y – 2b)
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