In a Gunn diode oscillator, the electron drift velocity was found to be 107 cm/second and the effective length is 20 microns, then the intrinsic frequency is:

The modes of operation of a Gunn diode are illustrated in a plot of voltage applied to the Gunn diode v/s frequency of operation of Gunn diode.

A

true

B

false

If the length of the intrinsic region in IMPATT diode is 2 µm and the carrier drift velocity are 107 cm/s, then the drift time of the carrier is:

A

10-11 seconds

B

2×10-11 seconds

C

2.5×10-11 seconds

D

none of the mentioned

If the length of the intrinsic region in IMPATT diode is 2 µm and the carrier drift velocity are 107 cm/s, then the nominal frequency of the diode is:

A

12 GHz

B

25 GHz

C

30 GHz

D

24 GHz

If the critical field in a Gunn diode oscillator is 3.2 KV/cm and effective length is 20 microns, then the critical voltage is:

A

3.2 V

B

6.4 V

C

2.4 V

D

6.5 V

Consider the following relational schema. Students(rollno: integer, sname: string) Courses(courseno: integer, cname: string) Registration(rollno: integer, courseno: integer, percent: real) Which of the following queries are equivalent to this query in English? “Find the distinct names of all students who score more than 90% in the course numbered 107” (I) SELECT DISTINCT S.sname FROM Students as S, Registration as R WHERE R.rollno=S.rollno AND R.courseno=107 AND R.percent >90 (II) Πsname (σcourseno = 107∧percent>90 (Registration ⋈ Students)) (III) {T | ∃S ∈ Students, ∃R ∈ Registration (S.rollno = R.rollno ∧R. courseno = 107 ∧ R.percent > 90 ∧ T.sname = S. sname)} (IV) {〈SN〉 | ∃SR∃RP(〈SR, SN〉 ∈ Students ∧ 〈SR, 107, RP〉 ∈ Registration ∧ RP > 90)}

A

I, II, III and IV

B

I, II and III only

C

I, II and IV only

D

II, III and IV only

In Gunn diode oscillator, the Gunn diode is inserted into a waveguide cavity formed by a short circuit termination at one end

A

true

B

false

Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R) Assertion (A): In Gunn effect, when electric field is varied from zero to a threshold value the drift velocity decreases. Reason (R): Beyond the threshold electric field, if the electric field is increased, the drift velocity is decreased and the diode exhibits negative resistance. In the light of the above statement, choose the most appropriate answer from the options given below:

A

Both (A) and (R) are correct and (R) is the correct explanation of (A)

B

Both (A) and (R) are correct but (R) is not the correct explanation of (A)

C

(A) is correct but (R) is not correct

D

(A) is not correct but (R) is correct

Consider the following statements related to oscillator circuits : 1. The tank circuit of a Hartley oscillator is made up of a tapped capacitor and a common inductor. 2. The tank circuit of a Colpitts oscillator is made up of a tapped capacitor and a common oscillator. 3. The Wien Bridge oscillator is essentially a two-stage amplifier with an RC bridge in the first stage, and, the second stage serving as an inverter. 4. Crystal oscillators are fixed frequency oscillators with a high Q-factor. Which of the following are true?

A

1, 2 and 3 only

B

2, 3 and 4 only

C

1, 2 and 4 only

D

1, 3 and 4 only

GaAs is used in fabricating Gunn diode. Gunn diode is:

A

bulk device

B

sliced device

C

made of different type of semiconductor layers

D

none of the mentioned

Consider the following diodes: 1. Gunn diode 2. Schottky diode 3. Crystal diode 4. Tunnel diode Which of these can be used as detector diodes?

A

1 and 2 only

B

2 and 4 only

C

3 and 4 only

D

1, 2, 3 and 4

In a Gunn diode oscillator, the electron drift velocity was found to be 107 cm/second and the effective length is 20 microns, then the intrinsic frequency is:

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