Forward Bias

Q. A point charge q is placed at a normal distance dfrom one edge of a semi-infinite large plate asshown in figure. Find net electric flux passingthrough this plateSemi infiniteplaten.

Q.

When a forward bias is applied to a p-n junction, it___________.

Q.

The diode used in the circuit shown in the figure has a constant voltage drop of 0.5 V at all currents and a maximum power rating of 100 milliwatts. What should be the value of the resistor R, connected in series with the diode for obtaining maximum current

1. 1.5 W

2. 5 W

3. 200 W

4. 6.67 W

Q. In a semiconductor, the number density of intrinsic charge carriers at ${27}^{\circ }\text{C}$ is $1.5\times {10}^{16}{\text{m}}^{-3}$. If the semiconductor is doped with impurity atom, the hole density increases to $4.5\times {10}^{22}{\text{m}}^{-3}$. The electron density in the doped semiconductor is $\times {10}^9{\text{m}}^{-3}$.

Q. For the transistor circuit shown below, if $\beta$ = 100, voltage drop between emitter and base is 0.7 V then value of $V_{CE}$ will be

1. 10 V
2. 5 V
3. 13 V
4. 0 V

Q. 14. An electric dipole having charges +q and-q are at a separation r.At d>>r along the axis of the dipole the field is proportional to

Q. In the circuit shown below, the reading of the ideal voltmeter V

Q. Which one of the following represents forward bias diode?

1. 
2. 
3. 
4. 

Q. total electric flux associated with unit positive charge in vacuum is

Q. In a p-n junction diode, the current I can be expressed asI=I0exp{(eV/2kBT)-1}is called the reverse saturation current, V is the voltageacross the diode and is positive for forward bias and negative forreverse bias, and I is the current through the diode, kBis theBoltzmann constant (8.6×10–5 eV/K) and T is the absolutetemperature. If for a given diode I0= 5 × 10–12 A and T = 300 K, then(a) What will be the forward current at a forward voltage of 0.6 V?(b) What will be the increase in the current if the voltage across thediode is increased to 0.7 V?(c) What is the dynamic resistance?(d) What will be the current if reverse bias voltage changes from 1 Vto 2 V?

Q.

Figure 3.35 shows a 2.0 V potentiometer used for the determination of internal resistance of a 1.5 V cell. The balance point of the cell in open circuit is 76.3 cm. When a resistor of 9.5 Ω is used in the external circuit of the cell, the balance point shifts to 64.8 cm length of the potentiometer wire. Determine the internal resistance of the cell.

Q.

Why is n-p-n preferred over p-n-p?

Q.

How does current flow in a PN junction?

Q. in a potentiometer experiment, when three cells A, B and C are connected in series, the balancing length is found to be 740 cm. if A and B are connected in series, balancing length is 440 cm and for B and C in series that 540 cm. Find the ratio of the emfs of the cells.

Q.

What happens to the width of Depletion layer in forward bias?

Q. The forward biased diode connection is:

1. 
2. 
3. 
4. 

Q. A rod is bent into a semi-circular arc of radius R. The rod has a uniform linear charge distribution A. Thepotential at the centre of the arc, point P is

Q.

Two 120V Light bulbs, one of 25W and other of 200W are connected on series across a 240V line. One bulb burnt instantly. Which one was burnt and why? Explain

Q.

An engine pull a 1500kg of car on a level road at a constant speed of 5m/s against a frictional force of 500N. Calculate the power expended by the engine. What extra power has the engine to expend in order to maintain the same speed of the car up an inclined plane having a gradient of 1in 10?

Q.

If the forward voltage in a semiconductor diode is doubled, the width of the depletion layer will

1. Become half

2. Become one-fourth

3. Remain unchanged

4. Become double

Q.

In an n-p-n transistor symbol, the arrow on the emitter is shown for?

Q. Current in the circuit will be (in amperes):

1. $\frac{5}{40}$
2. $\frac{5}{50}$
3. $\frac{5}{10}$
4. $\frac{5}{20}$

Q. how current flows when majority(in forward bias)/minority(in reverse bias) charge carriers recombine in depletion region of pn junction?

Q.

If a force F is applied on a body and it moves with a velocity v, the power will be

1. 

2. 

3. 

4. 

Q. The phenomenon of 'outwards bending of electric field lines at the edges' of the plates of a capacitor is called

1. Polarization of induced charge
2. Induction of charges
3. Fringing of the field
4. Electric susceptibility

Q. 37.A resistor R1 dissipates the PowerPC when connected to a certain generator. If the resistor R2 is put in series with R1 the power dissipated by R1 options 1) decreases 2)increases 3)remains the same 4)any of the above depending upon the relative values of R1 and R2

Q. An uniform electric field E exists between two parallel plates having opposite charges in each plates. an electron enters the field between the plates with speed v°. if the length of each plate is l then the angle with which electron deviates from its initial path

Q.

1. 4.3 kW

2. 860 kW

3. 4.3 W

4. 860 W

Q.

The forward bias voltage of a diode is changed from $0.6\mathrm{to}0.7\mathrm{V}$. The current changes from$5\mathrm{mA}\mathrm{to}15\mathrm{mA}$. Then its forward bias resistance is

1. $0.01\Omega$

2. $0.1\Omega$

3. $10\Omega$

4. $100\Omega$

Q.

How many volts can a diode handle