To be honest I am not fully qualified to answer this question as my major is in Mechanical Engineering. But I had done minor in ECE hence I would jot down some which were asked to me in Viva and some from my friend's suggestion.
- What is difference between analog and digital signal?
- Difference between electronics and electrical.
- Difference between modulation and demodulation. Give examples.
- Difference between AM and FM.
- Explain CDMA, TDMA and FDMA.
- Difference between CDMA and GSM.
- What is frequency?
- What is amplifier?
- What is closed and open system? What is feedback?
- What is Oscillator? What is Oscilloscope?
I recommend you to brush up simple definition of basic components. If you failed to answer these,it would automatically degrade you.
- What us tracking radar? What is sonar?
- What is impedance? Relationship between length of line and impedance.
- What is bipolar transistor? How is it changed with thermal resistance.
- What is Q factor?
- What is thermocouple? Explain Seebeck effect.
- Name different op-amp. Which one is a comparator.
- What is quasi-stable state?
- Draw oscillator waveform for resistor,capacitor and zener diode.
- Draw SCR circuit. Explain practical application.
- What is gain factor in control system?
- Transfer function of feedback control system.
Advanced questions are rarely been asked. Try to drag interviewer’s attention toward your internships and projects. That way you'd be more prominent toward questions.
All the best!