Electrical Engineering - Online Test
Q1. The separately excited dc motor in the figure below has a rated armature current of 20 A and a rated
armature voltage of 150 V. An ideal chopper switching at 5 kHz is used to control the armature
voltage. If La= 0.1 mH, Ra= 1 Ω, neglecting armature reaction, the duty ratio of the chopper to
obtain 50% of the rated torque at the rated speed and the rated field current is
Answer : Option D
Explaination / Solution:
No Explaination.
Q2. Which one of the following is NOT logically equivalent to ¬∃x (∀y (α) ∧ ∀z (β))?
Answer : Option A
Explaination / Solution:
No Explaination.
Q3. A single-phase SCR based ac regulator is feeding power to a load consisting of 5Ω resistance and 16 mH inductance. The input supply is 230 V, 50 Hz ac. The maximum firing angle at which the voltage across the device becomes zero all throughout and the rms value of current through SCR, under this operating condition, are
Answer : Option C
Explaination / Solution:
Q4. It is given that X, X .... XM at M non-zero, orthogonal vectors. The dimension of
the vector space spanned by the 2M vectors X, X, ....XM, - X, - X, ..... - XM is
Answer : Option C
Explaination / Solution:
For two orthogonal vectors, we require two dimensions to define them and similarly for three orthogonal vector we require three dimensions to define them. 2M vectors are basically M orthogonal vector and we require M dimensions to define them.
Q5. 
Consider the following Sum of Products expression, F.
The equivalent Product of Sums expression is
Answer : Option A
Explaination / Solution:
Q6. In the following sequential circuit, the initial state (before the first clock pulse) of the circuit is Q1Q0 = 00. The state (Q1Q0), immediately after the 333rd clock pulse is
Answer : Option B
Explaination / Solution:
Q7. In the Op-Amp circuit shown, assume that the diode current follows the
equation I = Ise P(V VT). For Vi = V, V = V, and for Vi = V, V = V. The relationship between V and V is
Answer : Option D
Explaination / Solution:
Here the inverting terminal is at virtual ground and the current in resistor and
diode current is equal i.e. 
Q8. Consider the following minterm expression for F. F(P,Q,R,S) = ∑ 0, 2, 5, 7, 8, 10, 13, 15 The minterms 2, 7, 8 and 13 are ‘do not care terms. The minimal sum of-products form for F is
Answer : Option B
Explaination / Solution:
Q9. The
field (in A/m) of a plane wave propagating in free space is given by
field (in A/m) of a plane wave propagating in free space is given byThe time average power flow density in Watts is
Answer : Option D
Explaination / Solution:
Q10. For a Hertz dipole antenna, the half power beam width (HPBW) in the E-plane is
Answer : Option C
Explaination / Solution:
The beam-width of Hertizian dipole is 1800 and its half power beam-width is 900
