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-JE ELECTRICAL-2021 QUIZ
Each question carries 1 mark.
Negative marking: 1/4 mark
Total Questions: 06
Time: 06 min.
Q1. To convert a galvanometer into a voltmeter one should connect a: –
(a) high resistance in series with galvanometer
(b) low resistance in series with galvanometer
(c) high resistance in parallel with galvanometer
(d) low resistance in parallel with galvanometer
Q2. A voltmeter must have a very high internal resistance so that the:
(a) accuracy is high
(b) resolution is high
(c) meter draws minimum current
(d) loading is maximum
Q3. Which starting method is not used in squirrel cage induction motors?
(a) Resistance in rotor circuit
(b) Resistance in stator circuit
(c) Auto-transformer starting
(d) Star delta starting
Q4. What is condition for maximum starting torque of three phase induction motor if R₂ and X₂ are rotor resistance and reactance respectively?
(a) R₂ = 0, X₂ = 1Ω
(b) R₂ = 2 X₂
(c) R₂ = 0.5 X₂
(d) R₂ = X₂
Q5. The supply voltage to an induction motor is reduced by 10% By what percentage, approximately, will the maximum torque decrease?
Q6. Insulation resistance of a cable of length 20 km is 2 MΩ. What will be the insulation resistance of the same cable but for a length of 200 km?
(a) 2 MΩ
(b) 20 MΩ
(c) 0.2 MΩ
(d) 200 MΩ
A Galvanometer can be converted into voltmeter by connecting a high resistance in series with it.
Sol. A voltmeter having very high resistance so that it will draw minimum current and drop will be negligible and will correctly measure the Circuit voltage.
▭(R_series=R_m (m-1) ) when ▭(m=I/I_m or V/V_m )
Sol. Rotor resistance starting is used only for slip-ring induction motor because rotor of squirrel cage induction motor is short circuited.
Sol. Starting torque (T_s)= (KR₂)/(〖R₂²〗^ +x₂²) (Here S=1)
For maximum value (d(T_s))/(dR₂)= 0
⇒ R_2=x₂ → condition for maximum starting torque.
Sol. For Induction motor: –
If V is reduced by 10% then
So, % change = (V^2-(0.9v)²)/V²×100
= 19%≃20 %
Sol. insulation resistance of cable ⍺ 1/ length