ISRO Electronics Sample Question Paper : Indian Space Research Organization
Organisation : ISRO/ Indian Space Research Organization
Subject : Electronics
Document Type : Sample Question Paper
Post : Scientist/Engineer
Website : https://www.isro.gov.in/
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Electronics Sample Question Paper :
1. 1 cm3 of pure Germanium at 20°C contains about 4.2×1022 atoms, 2.5×1013 free electrons and 2.5x1013holes. 0.001% of Arsenic doping donates an extra 1017 free electrons in the same volume.
Related : Indian Space Research Organisation ISRO Computer Science Sample Question Paper : www.pdfquestion.in/8531.html
The approximate number of holes in one cm3 in the doped semiconductor under equilibrium condition is
a. 6.25×109
b. 2.5x 1o9
c. 10.5x 1o9
d. 10x 17
2 Measurement of Hall coefficient enables the determination of
a. Temperature coefficient and thermal conductivity
b. Mobility and concentration of charge carriers
c. Fermi level and forbidden energy gap
d. None of the above
3 Silicon is not suitable for fabrication of light emitting diodes because it is : ‘
a. An indirect band gap semiconductor
b. A direct band gap semiconductor
c. A wide band gap semiconductor
d. A narrow band gap semiconductor
4 The band gap of elements arranged in ascending order is:
a. Diamond, Ge, Si
b. Si, Ge, Diamond
c. Ge, Si, Diamond
d. Diamond, Si, Ge
5 The following statements are made for NMOS & PMOS
1. The carrier mobility in NMOS is higher
2. PMOS require less area than NMOS
3. NMOS circuits are smaller than PMOS –
4. PMOS are faster in switching.
Of these, the true statements are :
a. 2 and 4 only
b. 2 and 3 only
c. 1 and 3 only
d. 1, 2 and 3 only
Mechanical :
Multiple Choice Questions :
11. A small plastic boat loaded with pieces of steel rods is floating in a bath tub. If the cargo is dumped into the water , allowing the boat to ?oat empty, the water level in the tub will
(a) Rise
(b) Fall
(c) Remains the same
(d) Rise and then fall
12. Viscosity of water in comparison to mercury is
(a) higher
(b) lower
(c) same
(d) unpredictable
13. Froude number is signi?cant in:
(a) Supersonic, as with projectile and jet propulsion
(b) Full immersion or completely enclosed flow, as with pipes, air crafts wings, nozzles, etc.
(c) Simultaneous motion through two fluids where there is a surface discontinuity, gravity forces and wave making effect, as with ship’s hulls
(d) All of these
14. The purpose of surge tank in a pipe line is to
(a) smooth-en the flow of water
(b) minimize friction losses in pipe
(c) prevent occurrence of hydraulic jump
(d) relieve pressure due to water hammer
15. Head loss in turbulent flow in a pipe
(a) varies directly as velocity
(b) varies inversely as square of velocity
(c) varies approximately as square of velocity
(d) varies inversely as velocity
16. A tank 1.5m stands on a trolly and is full of water. It has an price of diameter 0.1m at 0.3m from the bottom of the tank. if the orifice is suddenly opened and coefficient of discharge of the orifice is 0.60, then the propelling force on the trolley will be
(a) 69.37 N
(b) 67.39 N
(c)463.79 N
(d) 65.39 N
17. A model of a hydraulic turbine is tested at a head of 1/4‘“ of that under which the full scale turbine works. The diameter of the model is half of that of the full scale turbine. if N is the RPM of the full scale turbine, then RPM of the model will be
(a) N/4 l
(b) N/2 I
(c) N l
(d) 2N
18. Consider steady, in compressible and irrational flow through a reducer in a horizontal pipe, where the diameter is reduced from 20 cm to 10 cm. The pressure in the 20 cm pipe just upstream of the reducer is 150 kPa . The fluid has a vapour pressure of 50 kPa and a specific weight of 5 kN/m3 . Neglecting frictional effects, the maximum discharge (in m3 lsec ) that can pass through the reducer without causing capitations is
(a) 0.05
(b)0.16
(c) 0.27
(d)0.38
19. For the stability of a floating body, under the influence of’ gravity alone, which of the following is true?
(a) Metacentre should be below the centre of gravity
(b) Metacentre should be above the centre of gravity
(c) Metacentre and centre of gravity must lie on the same horizontal line
(d) Metacentre and centre of gravity must lie on the same vertical line
20. A smooth pipe of diameter 200mm carries water. The pressure in the pipe at Section 51 (elevation: 10m) is 50 kPa . At section 52 (elevation: 12 m ) the pressure is 20 kPa and velocity is 2 m/sec . Density of water is 1000 kg/ m3 and acceleration due to gravity is 9.8 m/ sec 2 . Which of the following is true?
(a) Flow is from $1 to $2 and head loss is
(b) Flow is from 52 to $1, and head loss is 0.53m
(c) Flow is from $1 to $2 and head loss is
(d) Flow is from 52 to $1 and head loss is 1.06m
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