Electrical Engineering - Online Test
Q1.
A rectangular waveguide of internal dimensions (a = 4 cm and b = 3 cm) is to be operated in TE11 mode. The minimum operating frequency is
Answer : Option A
Explaination / Solution:
Q2. A fully charged mobile phone with a 12 V battery is good for a 10 minute talktime. Assume that, during the talk-time the battery delivers a constant current of 2 A and its voltage drops linearly from 12 V to 10 V as shown in the figure. How much energy does the battery deliver during this talk-time?
Answer : Option C
Explaination / Solution:
The energy delivered in 10 minutes is
Q3. Assuming that the diodes in the given circuit are ideal, the voltage V0 is
Answer : Option B
Explaination / Solution:
No Explaination.
Q4. Consider a combination of T and D flip-flops connected as shown below. The output of the D flip-flops is connected to the input of the T flip-flop and the output of the T Flip-flop connected to the input of the D Flip-flop. 
Initially, both Q0 and Q1 are set to 1 ( before the 1st clock cycle). The outputs
Answer : Option B
Explaination / Solution:
Q5. 
In the circuit shown below, if the source voltage Vs = 100∠53.13° V then the Thevenin’s equivalent
voltage in Volts as seen by the load resistance RL is
Answer : Option C
Explaination / Solution:
No Explaination.
Q6. If a vector field 
is related to another vector field 
through 
which of the following is true? (Note : C and SC refer to any closed contour and any surface whose boundary is C . )
is related to another vector field through which of the following is true? (Note : C and SC refer to any closed contour and any surface whose boundary is C . )
Answer : Option B
Explaination / Solution:
Hence (B) is correct option.
Q7. To evaluate the double integral 
we make the substitution 
The integral will reduce to
we make the substitution The integral will reduce to
Answer : Option B
Explaination / Solution:
Q8. The second order dynamic system
has the matrices P, Q and R as follows:
The system has the following controllability and observability properties:
Answer : Option C
Explaination / Solution:
Q9. A 4-pole, separately excited, wave wound DC machine with negligible armature resistance is rated for 230 V and 5 kW at a speed of 1200 rpm. If the same armature coils are reconnected to forms a lap winding, what is the rated voltage (in volts) and power (in kW) respectively at 1200 rpm of the reconnected machine if the field circuit is left unchanged?
Answer : Option B
Explaination / Solution:
In wave wound, no. of parallel paths is 2.
In lap wound, no of parallel paths is A = p = 4.
Rated voltage = (230 × 2)/4 = 115 V
As no. of parallel paths is divided into four from two, the voltage reduces to half but power remains the same.
Q10. A balanced (positive sequence) three-phase AC voltage source is connected to a balanced, star
connected load through a star-delta transformer as shown in the figure. The line-to-line voltage
rating is 230 V on the star side, and 115 V on the delta side. If the magnetizing current is neglected and 
then what is the value of 
in Ampere?
then what is the value of in Ampere?
Answer : Option A
Explaination / Solution:
