University of Mumbai 2003 B.E APPLIED SCIENCES-I - Question Paper

APPLIED SCIENCES-I (JUNE. 2003)
part I
1.(a) Write 2 important points regarding diamond structure. How many atoms are there per unit cell? Derive its packing efficiency. (7)
(B) describe piezo-electric effect, and show how piezo electric oscillator produces ultrasound (with proper circuit diagram.) (5)
(c) A charge water drop is just floating in a uniform electric field of 250 V/M. obtain the charge on it. Given: Radius of water drop = 10-8 m, Density of water = 103 kg/m3. ,(5)

2. (a) What is potential barrier? How it is formed in a p-n junction? (6)
(b) What are matter waves? Mention at lowest 3 characteristics of them. (5)
(c)An ultrasonic beam of one cm wavelength is sent by a ship, returns from the sea bed after two sec. If velocity of ultrasonic beam in sea water is 1510 m/sec at 0°C, its salinity at 30°C is 29 gm/lit, compute the depth of sea bed at 30°C and frequency of ultrasonic beam. (6)

3.(a) Derive the formula for displacement of electron in transverse electric field. - (8)
(b) discuss the construction of C.R.O. and explain how AC, D.C. voltage, frequency and phase angle ranging from 2 A.C. voltage measured by C.R.O. (8)

4. (a) Draw the following:- (/ = learn as bar)
(i) (0 /1 1), (1 two 1), (1 /2 3) (3) (ii)(0 /1 1),(1 two 1),(1 two 3) (3)
(b) Show that for an instric semiconductors at low temperatures EF= (EC+EV)/2 where symbols have their usual meanings. (8)
(c)(i) At what angle to the magnetic field the charged particle should entre to experience maximum force? (1)
(ii) Show that magnetic force does not act on static charge. (1)
(iii) If the charged particle enters the magnetic field- either parallel or antiparallel to the field direction, what is the value of outcome force? (1)

5. Write short note on:
(a) Significance of ligancy in crystals. (5)
(b) Use of ultrasonic in Non-Destructive testing. (5)
(c) Electrostatic and Magnetostatic focusing. (6)
part II
(At wts : H = 1; Ca = 40; mg = 24; C = 12; O = 16; S = 32; Fe = 56)

6.Answer any 6 of the following:- (18)
(a) Why is hot lime soda process better than the cold process.
(b) List the difference ranging from addition and condensation polymerization.
(c) Define grease? Under which situation it is used as a lubricant.
(d) What is green house effect?
(e) discuss phosphate conditioning of water.
(f) An oil blend used was analysed for its acid value six ml of oil needed 3.5 ml. N/100 kOH. obtain its acid value state whether the blend can be still be useful for lubrication (density oil = 0.89).
(g) What is difference ranging from scale & sludge.
(h) discuss the significance of vulcanisation.

7. (a) discuss the demineralization of hard water, with a neat diagram and improper equations. (6)
(b) Give preparation properties and uses of silicon rubber. (6)
(c) Write a note on solid lubricants. (4)

8. (a) compute the volumes of lime and soda (90% pure each) needed for softening 25000 litres of hard water containing subsequent ions/chemicals. (6)
HCO3= 12.2 PPM; C02 = 4.4PPM;
Ca++ = 30PPM; Mg++ = 21.6 PPM;
Fe2O3= 15.4 PPM; H2SO4 = 4.9PPM.
(b) provide the manufacturing process, properties and uses of Bakelite. (6)

(c) describe lubrication, discuss boundary film lubrication. (4)
9. (a) What is air pollution? Mention different kinds of air pollutants and explain the effect of subsequent on environment: (7)
(i) Nitrogen oxides (ii) Hydrogen sulphide (iii) Sulphur dioxide.
(b) The hardness of 75,000 litres of a water sample was completely removed by a permutit. The exhausted permutit then needed 1500 litres of NaCl containing 117 mg of NaCl per litre regeneration compute the hardness of water sample. (5)
(c)Mention the different method used for fabricating plastics and explain the transfer moulding in detail? (4)

Earning:   Approval pending.