Friday, March 5, 2010

MOST LIKELY VIVA-VOCE QUESTIONS VTU physics lab

I-V CHARACTERISTICS OF ZENER DIODE
1. What is a semi conductor? Why it does not obey ohms law ?
2. What is a p-n diode ?
3. What is a zener diode ?
4. What do you mean by doping ?
5. Explain V-I characteristic curve of a diode.
6. What do you mean by knee voltage and break down voltage?
7. What do you mean by Zener resistance?
8. Explain break down mechanisms.
9. Explain the formation of depletion layer and junction potential.
10. What do you mean by Forward and Reverse Bias?
11. When junction is forward biased thickness of the depletion region decreases Why ?
12. When junction is reverse biased thickness of the depletion region increases Why ?
13. What is N –type and P-type semiconductor ?
14. What is rectifier diode?
15. What is the difference between rectifier diode and zener diode ?
16. What is the application of zener diode ?
17. What is symbol for rectifier diode and zener diode ?

TRANSISTOR CHARACTERISTICS
1. What is a transistor?
2. What are the differences between the emitter and collector?
3. Why the base region is made very thin?
4. Why the collector current is always less than the emitter current?
5. What is current gain in a transistor?
6. What are different types of transistors?
7. What are the applications of transistor?
8. What is input resistance of a transistor?
9. What is out put resistance of a transistor?
SERIES AND PARALLEL LCR RESONANCE
1. What is forced vibration damped vibration and Resonance?
2. What is the phase relation between the current and the applied voltage when current passes through a capacitor.
3. What is the phase relation between the current and the applied voltage when current passes through an inductance coil
4. Explain an electric oscillatory circuit in principle.
5. State Faraday’s laws of electromagnetic induction.
6. During series resonance the current flow is the maximum. Why?
7. Why a series resonance circuit is called acceptor circuit?
8. What happens to the Q factor when the resonance in sharp?
9. What is the condition for resonance of LCR circuit?

PLANK’S CONSTANT
1. What is light emitting diode?
2. What is the relation between energy and wave length?
3. What is knee voltage?
4. What is wave length corresponding to red, yellow, blue, green colures?
5. What is infra red radiation? What is the range of wave length?
6. What is the value of Planck’s constant?
7. What is the energy of quanta?

FERMI ENERGY
1. What is Fermi energy?
2. What is electrical conductivity?
3. What is the effect of temperature on the resistance of a metallic conductor?
4. What is the effect of temperature on the resistance of a semiconductor?
5. What is Fermi temperature?
6. What is Fermi voltage?
7. What is Fermi level?
8. What is relaxation time?
9. What is mean free path?

DIFFRACTION GRATING
1. What is diffraction of light? What is the condition to occur?
2. What is diffraction grating?
3. What is the difference between glass plate and grating?
4. What is LASER?
5. Define wave length.
6. What is monochromatic light?
7. What is grating constant?
8. What is the order of diffraction?

DIELECTRIC CONSTANT
1. What is dielectric?
2. What is the difference between dielectric materials and metals?
3. What is electric dipole?
4. What is electric dipole moment?
5. What is electric polarisation?
6. What is the effect of electric field on dielectric materials?
7. Define dielectric constant of a material.
8. Define time constant of RC circuit.
9. Explain the charging action of a capacitor.
10. What is an electrolytic capacitor?

B-H CURVE
1. What is hysteresis?
2. What is ferromagnetic material?
3. What are the 3 categories of the magnetic materials?
4. Explain diamagnetic, paramagnetic, ferromagnetic materials
5. What is hysteresis loss?
6. Explain magnetic hysteresis.
7. What are the different types of ferromagnetic material?

BAND GAP OF A SEMICONDUCTOR
1. What is band gap of semiconductor?
2. Explain energy band diagram of a semiconductor.
3. What is diode?
4. What is forward bias and reverse bias?

STEFAN’S CONSTANT USING BLACK BODY RADIATOR
1. What is a black body?
2. What is plank’s law of black body radiation?
3. What is Stefan’s law?
4. As temperature increases what happens to the conductivity of a metal?

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