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Exploring Physics, , Test-1, Semiconductor Devices, Question 1., Bonds in a semiconductor :, (a) trivalent. {b) covalent, (c) bivalent. (d) monovalent, Question 2., Number of electrons in the valence shell of a semiconductor is:, (a) 1 (b)2, (c)3 (d)4, Question 3., Semiconductors of both p-type and n-type are produced by:, (a) ionic solids. (b) covalent solids, (c) metallic solids. (d) molecular solids, Question 4., With fall of temperature, the forbidden energy gap of a semiconductor, (a) increases. (b) decreases, (c) remains unchanged (d) sometimes increases and sometimes decreases, Question 5., In a p-type semiconductor, current conduction is by:, (a) atoms. (b) holes, (c) electrons. (d) protons, Question 6., The material most commonly used to manufacture electronic solid state devices is :, (a) copper. {b) silicon, (c) germanium. (d) aluminium, Question 7., In reverse biasing:, (a) large amount of current flows. (b) no current flows, , (c) potential barrier across junction increases. (d) depletion layer resistance increases, , Question 8., , Main function of a transistor is to :, , (a) rectify. (b) simplify, , (c) amplify. (d) all the above, , Question 9., , To obtain p-type silicon semiconductor, we need to dope pure silicon with:, (a) Boron. (b) phosphorus, , (c) Antimony, (d)germanium, , Question 10., , On applying reverse bias to a junction diode, it:, , (a) lowers the potential barrier. (b) raise the potential barrier, , (c) increases the majority carrier current (d) increases the minority carrier current

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Question 11., , Which logic gate is known as inverter, (a)AND gate (b) OR gate. (c)NOR gate (d) NOT gate, , Question 12., , To obtain electrons as majority charge carriers in a semiconductors the impurity mixed is:, (a) monovalent. (b) divalent, , (c) trivalent. (d) pentavalent, , Question 13., , Binory number 1010 represent which decimal number:, , (ayo (b) 11 (c) 10 (ds, , Question 14., , In a common emitter amplifier the phase difference between the input signal voltage and output voltage is :, (a) m2 (b)0 (c) m/4 (d)x, , Question 15., , In semi conductor, at room temperature :, (a) The valence bond is partially empty and the conduction band is partially filled, (b) The valence band is completely filled and the conduction band is partially filled, ({c) the valence band is completely filled, ({d) The conduction band is completely empty, , Question 16., , In semi conductor which are responsible for conduction:, , (a) only electron. (b) electron and hole both, (c) only hole. (d) None of these, Question 17., , Winch of the following gate is a universal gate?, , (a)OR (b) NOT (c) AND (d) NAND, Question 18., , On heating, resistance of semiconductors:, (a) decreases. (b) increases. (c) remains same. (d) first increases then decreases, , Question 19., , p-n junction diode can be used as:, , (a) amplifier (b) oscillator. _ (c) detector (d) modulator, Question 20., , In intrinsic semiconductor at room temperature, the number of electrons and holes are:, (a) equal. (b) unequal, (c) infinite. (d) zero, , Question 21. Zener diode is used for:, (a) producing oscillations in a oscillator, (b) amplification, (c) stabilisation. (d) rectification, , , , Question 22., , The part of a transistor which is heavily doped to produce a large number of majority carriers is :, (a) base, (b) emitter, , (c) collector. (d) None of these