VSSC Electonic Mechanic Paper 2017

Vikram Sarabhai Space Centre Electonic Mechanic Paper 2017

The electrolyte used in Nickel-Cadmium rechargeable cell is
(a) Zinc chloride
(b) Aquesous solution of potassium hydroxide
(c) Mercuric oxide
(d) Nickel hydroxide

Hysteresis loss in a transformer is caused by
(a) Induced voltage in the core due to changing magnetic field
(b) Variation in input frequency
(c) Energy consumed in reversing the magnetism of iron core
(d) Fluctuation in load current

Two inductors of 32 mH and 8 mH are placed parallel to each other on a common core and are connected in series aiding. If the mutal inductance is 2 mH, the coefficient of coupling is
(a) 0.125
(b) 0.049
(c) 0.25
(d) 0.05

How many 2K x 8 ROM chips would be required to build a 16k x 8 memory system?
(a) 2
(b) 4
(c) 8
(d) 16

A transformer has a primary to secondary turns ratio of 1:2. 50V rms, 50Hz sine wave is applied at primary winding. The peak secondary voltage will be
(a) 100 V
(b) 25 V
(c) 141.4 V
(d) 35.35 V

A 240 kHz, 10Vpp carrier is amplitude modulated using a 1 kHz sine wave of 3 Vpp. What is the modulation index?
(a) 3.3
(b) 0.3
(c) 0.54
(d) 0.60

In an amplitude modulated signal, modulating frequency is 10 kHz and modulation index is 0.6. What should be the best suited RC time constant for the envelop detector?
(a) 0.52 msec
(b) 0.02 msec
(c) 0.20 msec
(d) 0.35 msec

The function of ALE signal in 8051 microcontroller is
(a) To extend the memory capacity
(b) To control demultiplexing the adress and data bus
(c) To distinguish between external RAM and PROM
(d) To initalize parallel port

Which of the following can be employed for position sensing?
(a) LDR
(b) RTD
(c) Potentiometer
(d) Optocoupler

Optical fibre communication works on the principle of
(a) Interference
(b) Total internal reflection
(c) Diffraction
(d) Photo Electric Effect