A potential barrier of 0.60 V exists across a p - n junction. (i) If the depletion region is 6.0 × 10 - 7 m thick, what is the intensity of the electric field in this region? (ii) If an electron with speed 5.0 × 10 5 m s - 1 approaches the p - n junction from the n -side, with what speed will it enter the p -side? Mass of electron, m = 9 .1 × 10 - 31 kg , charge of the electron, e = 1 .6 × 10 - 19

Given, The velocity of the electron, v 1 = 5 .0 × 10 5 ms - 1 The potential barrier, V = 0.60 V The thickness of the depletion region, d = 6.0 × 10 - 7 m We know the mass of the electron, m = 9 .1 × 10 - 31 kg The potential difference between two points depends on the work done by the field on a unit positive charge as it moves across the two points. Hence, the electric field becomes, E = V d = 0.60 6.0 × 10 - 7 = 1.0 × 10 8 Vm - 1 Say, the final speed is v 2 . Assume the initial potential energy is zero, then the final potential energy becomes, P E 2 = e V From the conservation of energy, 1 2 m v 1 2 = e V + 1 2 m v 2 2 ⇒ 1 2 × 9.1 × 10 - 31 × ( 5.0 × 10 5 ) 2 = 1.6 × 10 - 19 × 0.6 + 1 2 × 9.1 × 10 - 31 × v 2 2 ⇒ v 2 = 1.975 × 10 5 m s - 1 ≃ 2.0 × 10 5 m s - 1

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IMPORTANT

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The silicon diode shown in figure is rated for a maximum current of $100 m A .$ Calculate the minimum value of resistor $R$ . Assume the forward voltage drop across the diode to be $0.7 V$ .

Important Questions on Semiconductor Devices and Digital Circuits

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PHYSICS A Reference Book for Class 12 Volume 2>Chapter 6 - Semiconductor Devices and Digital Circuits>Problems For Practice>Q 5

Figure shows a diode connected to an external resistance and a battery. Assuming that the barrier developed in the diode is $0.5 V,$ obtain the value of current in the circuit in milliampere.
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12th CBSE

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PHYSICS A Reference Book for Class 12 Volume 2>Chapter 6 - Semiconductor Devices and Digital Circuits>Problems For Practice>Q 6

Find the current through the circuit and the potential difference across the diode shown in figure. The drift current for the diode is $20 μA$ .
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12th CBSE

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PHYSICS A Reference Book for Class 12 Volume 2>Chapter 6 - Semiconductor Devices and Digital Circuits>Problems For Practice>Q 7

Find the equivalent resistance of the circuit shown in figure between points $A$ and $B$ , for

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12th CBSE

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PHYSICS A Reference Book for Class 12 Volume 2>Chapter 6 - Semiconductor Devices and Digital Circuits>Problems For Practice>Q 8

Assuming that the resistances of the meters are negligible, what will be the readings of the ammeters $A_{1}$ and $A_{2}$ in the circuit shown in figure? Question Image

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12th CBSE

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PHYSICS A Reference Book for Class 12 Volume 2>Chapter 6 - Semiconductor Devices and Digital Circuits>Problems For Practice>Q 9

A potential barrier of

0.60 V

exists across a

p

n

junction. (i) If the depletion region is

6.0 \times 10^{- 7} m

thick, what is the intensity of the electric field in this region? (ii) If an electron with speed

5.0 \times 10^{5} m s^{- 1}

approaches the

p

n

junction from the

n

-side, with what speed will it enter the

p

-side? Mass of electron,

m = 9 .1 \times 10^{- 31} kg

, charge of the electron,

e = 1 .6 \times 10^{- 19}

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12th CBSE

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PHYSICS A Reference Book for Class 12 Volume 2>Chapter 6 - Semiconductor Devices and Digital Circuits>Problems For Practice>Q 10

A sinusoidal voltage of rms value $220 V$ is applied to a diode and a resistor $R$ in the circuit shown in figure, so that half-wave rectification occurs. If the diode is ideal, what is the rms voltage across $R$ ?

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12th CBSE

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PHYSICS A Reference Book for Class 12 Volume 2>Chapter 6 - Semiconductor Devices and Digital Circuits>Problems For Practice>Q 11

The applied input A.C to a half-wave rectifier is

100 W .

The D.C output is

40 W

. (i) What is the rectification efficiency? (ii) What is the power efficiency?

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12th CBSE

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PHYSICS A Reference Book for Class 12 Volume 2>Chapter 6 - Semiconductor Devices and Digital Circuits>Problems For Practice>Q 12

A crystal diode having internal resistance

200 Ω

is used as a half rectifier. If the applied voltage is

V = 50

s i n ω t

volt and load resistance is

800 Ω

, find (i) maximum output current (ii) d. c. output current (iii) d. c. output power and (iv) d. c. output voltage.

The silicon diode shown in figure is rated for a maximum current of 100 mA. Calculate the minimum value of resistor R. Assume the forward voltage drop across the diode to be 0.7 V.

Important Questions on Semiconductor Devices and Digital Circuits

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The silicon diode shown in figure is rated for a maximum current of $100 m A .$ Calculate the minimum value of resistor $R$ . Assume the forward voltage drop across the diode to be $0.7 V$ .