Transformers

41. In a transformer the resistance between its primary and secondary is

1. zero
2. 1 ohm
3. 1000 ohms
4. infinite

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42. In a transformer the resistance between its primary and secondary should be

1. zero
2. 10 Q
3. 1000 Q
4. infinity

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43. In a transformer the tappings are generally provided on

1. primary side
2. secondary side
3. low voltage side
4. high voltage side

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44. In an actual transformer the iron loss remains practically constant from noload to fullload because

1. value of transformation ratio remains constant
2. permeability of transformer core remains constant
3. core flux remains practically constant
4. primary voltage remains constant

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45. In the transformer following winding has got more cross-sectional area

1. Low voltage winding
2. High voltage winding
3. Primary winding
4. Secondary winding

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46. In the transformer the function of a conservator is to

1. provide fresh air for cooling the transformer
2. supply cooling oil to transformer in time of need
3. protect the transformer from damage when oil expends due to heating
4. none of the above

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47. Iron loss of a transformer can be measured by

1. low power factor wattmeter
2. unity power factor wattmeter
3. frequency meter
4. any type of wattmeter

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48. Losses which occur in rotating electric machines and do not occur in trans formers are

1. friction and windage losses
2. magnetic losses
3. hysteresis and eddy current losses
4. copper losses

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49. Material used for construction of transformer core is usually

1. wood
2. copper
3. aluminium
4. silicon steel

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50. Minimum voltage regulation occurs when the power factor of the load is

1. unity
2. lagging
3. leading
4. zero

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