BE Mechanical Engineering Semester 1 (FE First Year) - University of Mumbai Important Questions for Applied Physics 1

A quartz crystal of thickness 1.5 mm vibrating with resonance. Calculate it’s fundamental frequency if the Young’s modulus of quartz crystal is 7.9×10¹⁰N/m² and density is 2650 kg/m³ . 

Explain with example how to determine crystal structure by Bragg’s X-ray spectrometer.

Calculate the frequency and wavelength of photon whose energy is 75eV.

Obtain one dimensional time dependent time independent Schrodinger equation.

What is the significance of wave function ? derive the expression for energy eigen values for the free particle in one dimensional potential well.

Draw the energy band diagram  of p-n junction diode in forward and reverse bias condition .

Mobility of electron and hole in a sample of Ge at room temperature are 0.36 m² /V-sec and 0.17m² /V-sec respectively. If electron and holes densities are equal and it is 2.5 ×10¹³ /cm³ , calculate its conductivity.

State the Hall effect. Derive the expression for Hall voltage and Hall coefficient with neat diagram.

What is photovoltaic effect? Explain the principle and working of solar cell.

“Superconductor is a perfect diamagnetic”, Explain.

What is reverberation time? How it is important ? write the factors affecting reverberation time. 

A hall of dimension 25×18×12m³ has an average absorption coefficient 0.2. find the reverberation time. If a curtain cloth of area 150m² is suspended at the  centre of Hall with coefficient of absorption 0.75, What will be the reverberation
time?

State the piezoelectric effect. With neat circuit diagram explain the principle and working of piezoelectric oscillator .

What are crystal imperfections Mention any two significance of it .

Draw and explain the unit cell of sodium chloride (NaCl) crystal determine effective number of NaCl molecule per unit cell and co-ordination number.

 Explain analysis of crystal structure using Bragg’s X ray spectrometer

Calculate the critical radius ratio of an ionic crystal in ligancy-6 . what is the maximum size of cation in ligancy 6 configuration when size of anion is 2.02A°?

Draw the unit cell of HCP structure and work out the no. of atoms per unit cell.

What is the principle of solar cell? Write its advantages and disadvantages

Draw the following : (1,-1,3) ,(2,0,0) , [0,0,-1]
An electron is accelerated through 1200 volts and is reflected from a crystal. The second order reflection occurs when glancing angle is 60°. Calculate the inter planar spacing of the crystal.