The previous years question paper for recruitment at BHEL is as given below:


When a inductive coil connected to a 200 V, 50Hz ac supply with 10A current flowing through it dissipates 1000 watts then which of the following will have least value in ohms

a.) Resistance
b.) Reactance
c.) Impedance
d.) None

Oscillator crystal are made of –

a.) Silicon
b.) Germanium
c.) Quartz
d.) None

For small size, high frequency coils, the most common core material is-
a. )Air
b. )Ferrite
c.) Powdered ion
d.) Steel

A superconductor is a –

a.) A material showing perfect conductivity and Meissner effect below a critical temperature
b.) A conductor having zero resistance
c.) A perfect conductor with highest di-magnetic susceptibility
d.) A perfect conductor which becomes resistance when the current density through it exceeds a critical value



When an inductor tunes at 200 KHz with 624 pF capacitor and at 600 KHz with 60.4 pF capacitor then the self capacitance of the inductor would be –

a) 8.05 pF
b) 10.05pF
c.) 16.01pF
d.) 20.01pF

Sparking occur when a load is switched off because the circuit has high –

a.) Inductance
b.) Capacitance
c.) Resistance
d.) None

Sparking between contacts can be reduced by inserting a –

a.) Resistance in the line
b.) Capacitor in series with contacts
c.) Capacitor in parallel with contacts
d.) None

RF amplifier of an A.M. receiver is normally biased in –

a.) Class ‘A’
b.) Class ‘b’
c.) Class ‘C’
d.) None

The value of gate voltage for the operation of enhancement of only N channel MOSFET has to be –

a.) High positive
b.) High negative
c.) Low positive
d.) Zero

The input gate current of a FET is –

a.) a few microamperes
b.) negligibly small
c.) a few milliamperes
d.) a few amperes

A step recovery diode –

a.) has on extremely short recovery time
b.) conducts equally well in both directions
c.) is mainly used as a harmonic generator
d.) is an ideal rectifiers of high frequency signals

In a FET the electrode, which corresponds to collector in bipolar transistor, is –

a.) source
b.) drain
c.) gate
d.) none

The device which acts like an NPN and a PNP transistor connected base to base and emitter to collector is –

a.) Triac
b.) UJT
c.) Diac
d.) SCR

A typical optical fibre has –

a.) High refractive index core and low refractive index cladding
b.) Low refractive index core and high refractive index cladding
c.) Both a and b
d.) None