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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

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
  • 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

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