UPRVUNL’21 EE: Daily Practices Quiz 06-Sep-2021

UPRVUNL JE Recruitment 2021: 

A total of 196 vacancies were released by the UPRVUNL Recruitment 2021. The selection process will be based on the written examination which will be divided into two parts – Part I and Part II. Part I will have 150 objective-type questions from the syllabus for the Diploma Engineering in the relevant branch. While Part II will have 50 objective-type questions comprising General Knowledge, General Hindi, and Reasoning.

UPRVUNL’21 EE:  Daily Practices Quiz 06-Sep-2021

Each question carries 1 mark.

Negative marking: 1/4 mark

Total Questions: 06

Time: 08 min

Q1. In an electro dynamometer type Watt meter if the voltage and current measured are given by V = 100 sin 314t and I = 10 sin (314t – 60°) respectively, the reading (in watts) will be
(a) 1000
(b) 500
(c) 250
(d) 433

Q2. If a dynamometer wattmeter is connected in an ac circuit, the power indicated by the wattmeter will be
(a) volt-ampere product
(b) average power
(c) peak power
(d) instantaneous

Q3. A capacitor is generally a
(a) bilateral and active component
(b) active, passive, linear and non-linear component
(c) linear and bilateral component
(d) non-linear and active component

Q4. Differentially compound D.C. motors can find applications requiring
(a)high starting torque
(b) variable speed
(c) low starting torque
(d)frequent on-off cycles

Q5. For high efficiency of transfer of power, internal resistance of the source should be
(a) equal to the load resistance
(b) less than the load resistance
(c) more than the load resistance
(d) none of the above

Q6. Which of the following single-phase motors is suitable for timing and control
purposes?
(a) Reluctance motor
(b) Series motor
(c) Repulsion motor
(d) Universal motor

SOLUTIONS
S1. Ans.(c)
Sol. V=100 sin⁡〖314 t〗
i=10 sin⁡(314 t-60°)
ϕ=θ_V-θ_i=0-(-60)
=60°
P=V_rms 〖 I〗_rms cosϕ
=(100/√2)(10/√2) cos⁡60°
=(100×10×1)/(2×2)
=250 watt

S2. Ans.(b)
Sol. Two wattmeter for unbalanced load: –
tanθ= √3 ((W_2-W_1)/(W_2+W_1 ))
⇒θ=tan^(-1) √3 ((W_2-W_1)/(W_2+W_1 ))
So, power factor =cosθ={tan^(-1) √3 ((W_2-W_1)/(W_2+W_1 ))}

S3. Ans.(c)
Sol. Linear and bilateral component.

S4. Ans.(c)
Sol. Differentially compound d.c. motors are used for low starting torque requirements.

S5. Ans.(a)
Sol. For high efficiency of transfer of power R_S=R_L (Maximum Power transfer theorem)
R_S= Source resistance
R_L= Load resistance

S6. Ans.(a)
Sol. Reluctance Motor

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