Q. Assertion (A): The conductivity of p type semiconductor is higher than that of intrinsic semiconductor.

Reason (R): The addition of donor impurity creates additional energy levels below conduction band.

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Q. A particular green LED emits light of wavelength 5490, Å, the energy bandgap of the semiconductor material used there is .. h = 6.6 x 10¯³⁴ J sec.

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Q. Assertion (A): The reverse saturation current in a semiconductor diode is 4nA at 20°C and 32 nA at 50°C.

Reason (R): The reverse saturation current in a semiconductor diode doubles for every 10°C rise in temperature.

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Q. The value of a in a transistor

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Q. The intrinsic carrier concentration of silicon sample at 300 K is 1.5 x 1016/m³. If after doping, the number of majority carriers is 5 x 1020/m³. The minority carrier density is

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Q. Two identical silicon diodes D1 and D2 are connected back to back shown in figure. The reverse saturation current Is of each diode is 10-8 amps and the breakdown voltage VBr is 50 v. Evaluate the voltages VD1 and VD2 dropped across the diodes D1 and D2 assuming KT/q to be 25 m V.

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Q. An one sided abrupt junction has 10²¹/m³ of dopants on the lightly doped side, zero bias voltage and a built-in potential of 0.2 V. The depletion width of abrupt junction.(q = 1.6 x 10¯¹⁹ C, εr =16, ε₀ = 8.87 x 10¯¹² F/m) is

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Q. n-type semiconductors

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Q. In all metals

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Q. The voltage across a zener diode

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Q. Assertion (A): Two transistors one n-p-n and the other p-n-p are identical in all respects (doping, construction, shape, size). The n-p-n transistor will have better frequency response.

Reason (R): The electron mobility is higher than hole mobility.

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Q. In which of the following is the width of junction barrier very small?

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Q. If the reverse voltage across a p-n junction is increased three times, the junction capacitance

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Q. Which of these has highly doped p and n region?

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Q. Measurement of Hall coefficient enables the determination of

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Q. The units for transconductance are

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Q. The mean free path of conduction electrons in copper is about 4 x 10¯⁸ m. For a copper block, find the electric field which can give, on an average, 1 eV energy to a conduction electron

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Q. When a p-n-p transistor is properly biased to operate in active region the holes from emitter.

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Q. Assertion (A): Silicon is preferred over germanium in manufacture of semiconductor devices.

Reason (R): Forbidden gap in silicon is more than that in germanium.

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Q. Assertion (A): A decrease in temperature increases the reverse saturation current in a p-n diode.

Reason (R): When a diode is reverse biased surface leakage current flows.

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