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__indian Space Research Organisation(ISRO)__

__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**

- 0.015 joules.
**0.15 joules.**- 0.5 joules.
- 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

_____________________________________________**Also Read - Electrical engineering Important Questions Practice For HPCL | GATE | ISRO | BARC | UPSC-ESE | UPPSC**

_____________________________________________**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