1. consider the following equivalent circuit model of a bipolar transistor at a certain bias point (vbe, vbc) in the forward-active regime. a) calculate ic at which the device is biased. b) calculate the current gain, βf, of the transistor. c) calculate the short-circuit current-gain cut-off frequency, ft, of this device at this bias point. d) calculate the early voltage, va, of the transistor. e) derive values for all small-signal elements of the equivalent circuit model of another transistor fabricated side-by-side to the one above but with an emitter stripe length that is twice as long. the device is biased at the same voltages (vbe, vbc) as the above device

What produces light and all other electromagnetic waves? a) the photoelectric phenomena b) heated metals c) charged particles d) radioactive samples (pls explain if you can : )

The intensity of a polarized electromagnetic wave is 12 w/m^2. part a) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=0∘ with the plane of polarization? part b) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=30∘ with the plane of polarization? part c) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=45∘ with the plane of polarization? part d) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=60∘ with the plane of polarization? part e) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=90∘ with the plane of polarization?

Aparticle moves in the xy plane with constant acceleration. at time zero, the particle is at x = 6 m, y = 8.5 m, and has velocity ~vo = (9 m/s) ˆı + (−2.5 m/s) ˆ . the acceleration is given by ~a = (4.5 m/s 2 ) ˆı + (3 m/s 2 ) ˆ . what is the x component of velocity after 3.5 s? answer in units of m/s.