### infosys question papers 2015|infosys latest question and answers papers2015

A.A certain transformer has 200 turns in the primary winding and 3,000 turns in the secondary winding. The turns ratio is

A. 0.2

B. 0.4

C. 5

D. 30

B.What kVA rating is required for a transformer that must handle a maximum load current of 8 A with a secondary voltage of 3 kV?

A. 4 kVA

B. 0.25 kVA

C. 16 kVA

D. 8 kVA

C.The turns ratio required to match an 110 source to a 320 load is

A.80

B.20

C.4

D.2

D.If a transformer has 50 turns in the primary winding and 11 turns in the secondary winding, what is the reflective resistance if the secondary load resistance is 250 ?

A.250

B.20

C.6,250

D.62,500

E.When the turns ratio of a transformer is 25 and the primary ac voltage is 15 V, the secondary voltage is

A.10 V

B.120 V

C.240 V

D.2,400 V

F.If 20 W of power are applied to the primary of an ideal transformer with a turns ratio of 10, the power delivered to the secondary load is

A. 25 W

B. 0 W

C. 250 W

D. 2.5 W

G.A transformer with a 111 V primary has a 15:1 turns ratio. The load resistance, RL, is 120 . What is the approximate voltage across the load?

A.7.3 V

B.73 V

C.88 V

D.880 V

H.The primary winding of a transformer has 110 V ac across it. What is the secondary voltage if the turns ratio is 8?

A.8.9 V

B.88 V

C.880 V

D.8,800 V

I.To step 110 V ac down to 10 V ac, the turns ratio must be

A. 5.5

B.18

C.0.18

D.0.018

J.The mutual inductance when k = 0.65, L1 = 2 H, and L2 = 5 H is

A.2 mH

B.2 H

C.4 H

D.8 H