PPSC Physics Chapter 6 Electricity and Magnetism With Answers

image
image
image

PPSC Physics Chapter 6 Electricity and Magnetism

Sr. # Questions Answers Choice
1 A gallium atom is. Monvalent Diavalent Trivalent Pentavalent
2 A germanium atom is Monovalent Diavalent Travalent Tetravalent
3 At room temperature the p.d. between the two sides of depletion region for germanium is of the order of. 0.3 V 0.5 V 0.7 V 0.9 V
4 at room temperature the p.d. between the two sides of depletion region for silicon is of the order of. 0.3 V 0.5 V 0.7 V 0.9 V
5 A charge less region which separates p-type and n-type semiconductors in a p-n junction is known as. Polar region Null region Depletion region Neutral region
6 The current passing across a p-n junction due to minority charge carriers is called Reverse current Forward current Leakage current Both a and b
7 A p-type material is formed then a semiconductor is doped with Trivalent impurity Tetravalent impurity All of above A material having excess of free electrons
8 In a n-type material there is an excess of. Free electrons Holes Quarks Measons
9 In half wave rectifier the rms value of A.C. component of the wave is. More than A.C. Value Less than D.C. value Same as that of D.C. Not detectable
10 Why is an oxide coated filament used in vacuum tube. It has a longer lime Irt can with stand high It emit electrons at low temperature It reduces the effect of space charge
11 Where is the velocity of electrons maximum in a diode. Near the cathode Near the anode In the space ini between the two elecrode. It is same throughout the tube
12 A vacuum diode conducts when plate Is negative w.r.t cathode Is positive w.r.t. cathode and cathode are at the same potential Resistance is less
13 Which of the following material could be used for a high vacuum, high voltage tube. Thoriated tungsten Tungsten Copper Cesium
14 The thermionic current increases when Area of filament is decreased Area of filament is increased Temperature is decreased Work function is increased
15 Efficiency of a half wave recitifier is. Almost negigible More than full wave rectifier Less than full wave rectifier Equal to full wave rectifier
16 When forwarded bias is applied to a junction diode it. Increases the potential barrier Decreases the potential barrier Reduces the majority carrier current to zero Reduces the minority carrier current to zero
17 Which of the following is not an application of diodes. A filters Bridge rectifier Half wave rectifier Full wave rectifier
18 Since a diode permits the flow of current only in one direction so it can be used as. An oscillator A rectifier A phot deflector A transistor
19 What for is semiconductor diode used. To convert D.C. to A.C. To convert A.C. to D.C. To increase voltage To decrease voltage
20 A forward based p-n semiconductor diode is called. Photodiode Photovoltaic cell Amplifier Ligh emitted diode
Download This Set

Is this page helpful?

×