Second Year Physics Electronics

$A photo diode is a semi-conductor device usually made fromA) NitrogenB) OxygenC) CarbonD) Silicon$

$18.12 Tick (\checkmark) the correct answer(v) The common emitter current amplification factor \beta is given bya. \frac{I_{\mathrm{C}}}{I_{\mathrm{E}}} b. \frac{I_{\mathrm{C}}}{I_{\mathrm{B}}} C. \frac{I_{\mathrm{E}}}{I_{\mathrm{B}}} d. \frac{I_{\mathrm{B}}}{I_{\mathrm{E}}}$

$Hole is equivalent to:A) A neutral particleB) A positive chargeC) A negative chargeD) An electron$

$16.3 A radlo transmitter has a vertical antenna. Does It matter whether the recelving antenna is vertlcal or hortzontal ?$

$16.3 A nanosecond is 10^{-9} \mathrm{~s} (a) What is the frequency of electromagnetic wave whose period is lns?(b) What is its wave length? (c) To what class of electromagnetic waves does it belong?$

$Velocity of electromagnetic waves depends upon and electric permittivity:A) LongitudeB) Magnetic permeabilityC) Electric fieldD) None of these$