WAEC Physics questions: Introductory electronics

9 questions with answers and explanations. Tap an option to check yourself.

1. Question 1· Introductory electronics· WAEC

   A semiconductor diode is mainly used as a

   • Arectifier
   • Bamplifier
   • Ccapacitor
   • Dtransformer

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2. Question 2· Introductory electronics· WAEC

   Adding a pentavalent impurity such as phosphorus to pure silicon produces

   • Aa p-type semiconductor
   • Ban n-type semiconductor
   • Can insulator
   • Da superconductor

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   Explanation and discussion

3. Question 3· Introductory electronics· WAEC

   The output of an OR gate is 0 only when

   • Aall its inputs are 1
   • Ball its inputs are 0
   • Cany input is 1
   • Dthe inputs are different

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4. Question 4· Introductory electronics· WAEC

   A p–n junction diode is forward biased when the p-side is connected to the

   • Aearth only
   • Bnegative terminal of the battery
   • Cpositive terminal of the battery
   • Dcollector of a transistor

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5. Question 5· Introductory electronics· WAEC

   A semiconductor diode allows current to flow

   • Ain one direction only
   • Bin both directions equally
   • Conly with a.c.
   • Dnever

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6. Question 6· Introductory electronics· WAEC

   Silicon doped with boron becomes

   • Aa p-type semiconductor
   • Ban n-type semiconductor
   • Ca conductor
   • Dan insulator

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   Explanation and discussion

7. Question 7· Introductory electronics· WAEC

   A device that changes a.c. to d.c. is a

   • Arectifier
   • Btransformer
   • Camplifier
   • Dcapacitor only

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   Explanation and discussion

8. Question 8· Introductory electronics· WAEC

   A device that converts light energy directly into electrical energy is a

   • Asolar cell
   • Bdiode lamp
   • Ctransformer
   • Dthermocouple

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9. Question 9· Introductory electronics· WAEC

   The three terminals of a transistor are the

   • Aanode, cathode and grid
   • Bemitter, base and collector
   • Csource, gate and drain
   • Dpositive, negative and earth

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   Explanation and discussion