**Part A**

**Question : 1 [1*2.5 marks]**

a) Define the term accuracy.

b) In a simple pendulum in successive measurement the reading from out to be 2.63s, 2.42s, 2.71s and 2.80s. Calculate the absolute errors . Relative error or percentage error.

c) What is diffraction grating ? Give its use.

d) How one can minimize chromatic aberration associated with the lens ?

e) Define acceptance angle and Numerical aperture. Write down the relation between them.

f) Explain how the glass fiber guides light from one end to the other.

g) Given importance of studying elastic properties of materials.

h) Explain all the difference between longitudinal strain and lateral strain.

i) What will happen to simple harmonic motion if the damping frequency is greater than natural frequency ?

j) What is the maximum acceleration of a platform that oscillates at amplitude 2.20 cm and frequency 6.60 Hz ?

Part B

**Question : 2**

a ) i ) What is spherical aberration and discuss about lateral and longitudinal spherical aberration. [10]

ii) Discuss in detail about resolving power [5]

or

b) i ) Derive an expression for intensity in double-alt interface [10]

ii) Derive an expression for half-width of central line. [5]

**Question : 3**

a) A glass clad fiber is made with core glass of refractive index 1.5 and cladding is doped to give a index difference of 0.0005. Determine

i) the cladding refractive index

ii) the critical refraction angle

iii) the critical acceptance angle and

iv) numerical aperture [15]

or

b) Explain

i) Critical angle

ii) Acceptance cone

ii) Numerical Aperture [15]

**Question : 4**

a) What is the physical signification of bulk's modules ? Derive the relation between young's modules and Bulk modules of a given material. [15]

or

b) Determine the changes in length, breadth and thickness of a steel bar which is 4m long, 30mm wide and 20mm thick and is subjected to an axial pull of 30kN in the direction of its length. Take E=200,000 N/mm' and Poisson's ratio = 0.3. [15]

**Question : 5**

a) i) A 1 gm mass is suspended from a vertical spring. It execute simple harmonic motion with period of 0.1 sec. By how much distance had the spring stretched when the mass was attached ? [10]

ii) Calculate the potential energy of spring mass system doing SHM about its equilibrium position. [5]

or

b) What is resonance phenomenon is case of forced vibrations ? Give two examples for the same, By deriving the expression for amplitude resonance show that with increase in damping the resonance occurs. [15]

**Question : 6**

a) What is a decibel scale ? How the intensity in case of sound waves is directly proportional to the square of displacement amplitude ? [15]

or

b) Derive an equation for general Doppler effect and frame one example where this effect is applicable. [15]

**Question Paper**

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