# ISRO Scientist/Engineer Questions | important Question for Upcoming ISRO exam| Technical job Questions

### indian Space Research Organisation(ISRO) SCIENTIST/ENGINEER  Questions | important Question for Upcoming ISRO exam| Technical job Questions | previous year question papers for ISRO SCIENTIST/ENGINEER  Exam 2013

Electrical Engineering Questions

Q1. The energy stored in the magnetic field in a solenoid of length 30cm and diameter 3cm wound with 1000 turns of wire & carrying a current of 10A is
1.  0.015 joules.
2.  0.15 joules.
3. 0.5 joules.
4. 1.15 joules

Q2. A network is said to be linear, if and only if
• a) The response is proportional to the excitation function.
• b) The principle of superposition applies.
• c)The principle of homogeneity applies.
• d) The principles of superposition and homogeneity apply.

Q3. Kirchoff's law fails in the case of
• a) Non-linear networks.
• b) Linear networks.
• c)Dual networks.
• d) Distributed parameter networks

Q4. In a four branch parallel circuit, 50mA current flows in each branch. If one of the branches opens, the current in other branches
• a) Increase, but not double.
• b) Decrease.
• c) Unaffected.
• d) Double.

Q5. The wave length of a wave in a waveguide is
• a) is greater than in free space
• b) depends only on the waveguide dimensions and the free-space wavelength
• c) is inversely proportional to the phase velocity
• d) is directly proportional to the group velocity

Q6. Characteristic impedance of a quarter wave transformer connected in between a load of 100 ohm and a transmission line of characteristic
impedance 225 ohms is
• a) 100 ohm
• b) 225 ohm
• c) 600 ohm
• d) 150 ohm

Q7. A transverse electromagnetic wave with circular polarization is received by a dipole antenna due to polarization mismatch. The power transfer efficiency from the wave to the antenna is reduced to about
• a) 50%
• b) 35.5%
• c) 25%
• d) 0%

Q8. The unit of displacement density of a magnetic circuit is
• a) Coulomb/ metre
• b) Coulomb / sq. metre
• c) Newton - cm
• d) Amp/ metre

Q9. The derivative of an ideal step function is
• a) an impulse function
• b) zero
• c) sine function
• d) undefined

Q10. An impulse function consists of
• a) entire frequency range with same relative phase
• b) infinite bandwidth with linear phase variation
• C) pure DC
• d) large DC with weak harmonics
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Q11. The discrete time system described by y(n) = x(n>) is
• a) causal, linear and time varying
• b) causal, nonlinear and time varying
• c)non-causal, linear and time invariant
• d) non-causal, non linear and time variant

Q12. What does the transfer function of a system describe for the system?
• a) only zero input response
• b) only zero state response
• c) both zero input and zero state response
• d) neither zero input response nor zero state response

Q13. Which of the following measures cannot be effective in reducing the noise?
• a) reduction in signaling rate
• b) increase in transmitted power
• c) increase in chanhel bandwidth
• d) use of redundancy

Q14. Which among the following type of transformer have smallest size with same electrical specification ?
• a) ONAN type transformer.
• b) Dry type transformer.
• c) ONAF type transformer.
• d) OFWF type transformer.

Q15. Two transformers operating in parallel will share the load depending upon their
• a) Ratings.
• b) Leakage reactance.
• c) Efficiency.
• d) Per unit impendence.

Q16. Transformer core is laminated,
• a) because it is difficult to fabricate solid core.
• b) because laminated core provides high flux density.
• c) to avoid eddy current and hysteresis losses.
• d) to increase the main flux.

Q17. The eddy current losses in the transformer will be reduced if ?
• a) The laminations are thick.
• b) Number of turns in the primary winding is reduced.
• c) The number of turns in the secondary winding is reduced.
• d) The laminations are thin.

Q18. The Buchholz relay is used to protect the?
• a) Alternators against all internal faults
• b) Oil immersed transformers against all internal faults.
• c) Synchronous motors against all internal faults.
• d) Transmission lines against all short circuit faults.

Q19. Why are transformer stamping annealed before being used for the
building?
• a) to reduce eddy-Current loss due to burning
• b) to reduce hysteresis loss due to burning
• C) to give mecnanical strength to the core
• d) to increase core permeability