Transforms

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Q1:-The transformer is commonly used because 

1. it has high efficiency
2. frequency remains constant 
3. construction cost per KVA less as compared to other machine 
4. all of the above

ANSWER:-4

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Q2:-In an ideal transformer on no load the primary applied voltage is balanced by 

1. the secondary voltage 
2. the drop across resistance and reactance.
3. the secondary induced emf
4. the primary induced emf

ANSWER:-3

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Q3:-The voltage transformation ratio is 

1. E1/E2
2. N1/N2
3. E2/E1
4. none of these

ANSWER:-3

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Q4:- A transformer operates 

1. always at unity pf
2. has its own pf 
3. at a pf below a particular value
4. at pf depending on the pf of the load

ANSWER:-4

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Q5:-Which of the following is a correct statement about eddy current ?

1. eddy current improve the efficiency of a motor
2. eddy currents do not influence the movement 
3. eddy currents heat up the metal parts 
4. eddy currents are used are winding
5. ANSWER:-3

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