Materials And Components - Study Mode

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[#196] A hetero-structure laser is better than a diode laser (injection laser) because of its

(A) Low cost

(B) Long wavelength emission

(C) Low threshold current

(D) Nonlinear operation

Correct Answer

(C) Low threshold current

[#197] Match List-I with List-II and select the correct answer using the options given below: List-I (Material) List-II (Properties) a. Superconductor at very low temperature 1. High frequency b. Fabric chloride 2. Very small -ve susceptibility c. Diamond 3. Very high -ve susceptibility d. Manganese oxide 4. Susceptibility is inversely proportional to +θ (Here T is temperature of the material in Kelvin. θ is a constant for a material).

(A) a-2, b-4, c-3, d-1

(B) a-3, b-1, c-2, d-4

(C) a-2, b-1, c-3, d-4

(D) a-3, b-4, c-2, d-1

Correct Answer

(B) a-3, b-1, c-2, d-4

[#198] As the atoms of rare gases become larger, electronic polarizability

(A) Increases

(B) Decreases

(C) Remains the same

(D) May increase or decrease

Correct Answer

(C) Remains the same

[#199] Hall effect is observed in a specimen (metal or semi conductor) when it is carrying current and is placed in a magnetic field. The resultant electric field inside the specimen is

(A) Normal to both current and magnetic field

(B) In the same direction as current

(C) In a direction anti parallel to magnetic field

(D) None of the above

Correct Answer

(A) Normal to both current and magnetic field

[#200] The phenomenon of dielectric hysteresis occurs with

(A) DC

(B) AC

(C) Both AC and DC

(D) None of the above

Correct Answer

(B) AC