This is question 1 (null marks) from the GTU Engineering Physics BE Winter 2018 question paper. Subject code: 2110011.

WinterBE2018

Engineering Physics — Winter 2018

Subject Code2110011

ProgramBachelor of Engineering

Total Marks70

Questions78

Exam Date3 January 2019

Exam Time10:30 AM TO 1:00 PM

Questions78

1 to 100 nm

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Ball Milling

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Plasma Arching

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Melt Spinning

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CVD 4. The basic principle behind fiber optic communication is

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Reflection

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Refraction

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Diffraction

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Total Internal Reflection 5. Particle size of nano particle is

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0.1 to 1 nm

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10 to 100 nm

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1 to 10 nm 6. Weber Fechner law is

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L = K / log I10

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I = K / log L10

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L = Klog I10

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I = Klog L10 7. The superconducting state is perfectly ____ in nature

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Diamagnetic

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Paramagnetic

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Ferromagnetic

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All of the above

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Objective Question (MCQ) Mark

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07 1. Unit of absorption coefficient is

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a & c both 2. Frequency of ultrasonic waves is

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{)

f = 20 kHz

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f > 20 kHz

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})

f < 20 kHz

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f = 20 Hz 3. According to Snell’s law

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n /n = sinØ /sinØ

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n /n = sinØ /sinØ

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n /n = sinØ + sinØ

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n /n = sin2Ø /sin2Ø 4. Which event is likely to take place when a photon of energy equal to the difference in energy between two levels is incident in a system?

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Absorption

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Absorption and Emission

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None of the above 5. The current required to destroy the superconducting property is equal to

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I = 2𝜋rH C O

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I = 2𝜋H C C

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I = 2𝜋rH C C

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I = 4𝜋rH C C 6. The relation between permeability and susceptibility is

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μ = 1/χ r

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μ = 1 – χ r

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μ = χ r

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μ = 1 + χ r 7. The magnetic induction is equal to B =

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07 1. Super elasticity is observed by

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Biomaterials

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Shape Memory Alloys

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Metallic glasses

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None of the above 2. ____dB is the sound level for the threshold of pain

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10-12 dB 3. _____ is the process to synthesize metallic glasses

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Ahall has a volume of 2,265 m3. Its total absorption is equivalent to 94.85 m2 of open window. What will be the effect on reverberation time if the audience fill the hall and thereby increase the absorption by another 94.85 m2?

[3 marks]

Based on what factor superconductors are classified? Explain the types, which one has more applications? Give the reason for your answer.

[4 marks]

Describe the following terms 1) Sound absorption coefficient 2) Reverberation time

[4 marks]

Discuss Meissner effect in superconductors.

[3 marks]

Explain Ball Milling technique for the production of nano particles with its merits and demerits.

[7 marks]

Discuss the disadvantages of nano-materials

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Given the equation B = μH, B = Magnetic flux density μ = Absolute permeability H = Magnetic field strength Derive the relation between relative permeability and magnetic susceptibility

[3 marks]

What are Shape memory alloys? Discuss their two properties in detail.

[7 marks]

Derive the Clausius Mossotti equation.

[4 marks]

If we want to increase the intensity level by 1 dB, how many times should the intensity become? Explain the answers with necessary steps.

[3 marks]

Define and derive the equations for Acceptance angle and Numerical aperture.

[7 marks]

Describe the characteristics of LASER in detail.

[4 marks]

Calculate the refractive index of the core and cladding material of an optical fiber with numerical aperture 0.11 and relative refractive index difference is 0.011

[3 marks]

What are ultrasonic waves? Describe the piezoelectric method for production of ultrasonic waves with its merits and demerits.

[7 marks]

Explain the following terms in detail 1) Electric field 2) Dielectric constant

[4 marks]

The critical temperature for lead is 7.1 K. At 6 Kthe superconducting property disappears if it is subjected to magnetic field of 4.67 × 104 Am-1. Determine the value of the magnetic field required to destroy superconducting property at 0 K.

[3 marks]

Describe soft and hard magnetic materials in detail.

[7 marks]

What are Metallic glasses? Explain the melt spinning process for their preparation.

[4 marks]

Define the following terms. 1) Magnetic moment 2) Magnetic susceptibility 3) Intensity of magnetization

[3 marks]