An ideal transformer will have maximum efficiency at a load such that

A single phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at half load at the same power factor is -

A

87.8%

B

86.7%

C

88.26%

D

88.9%

In testing a pile by load test, pile platform is loaded with one and half times the design load and a maximum settlement is noted. The load is gradually removed and the consequent rebound is measured. For a safe pile, the net settlement (i.e. total settlement minus rebound) per tonne of test load should not exceed

A

10 mm

B

15 mm

C

20 mm

D

25 mm

For a transformer, operating at constant load current, maximum efficiency will occur at

A

0.8 leading power factor

B

0.8 lagging power factor

C

zero power factor

D

unity power factor

The simply supported beam 'A' of length '$$l$$' carries a central point load 'W'. Another beam 'B' is loaded with a uniformly distributed load such that the total load on the beam is 'W'. The ratio of maximum deflections between beams 'A' and 'B' is

A

$$\frac{5}{8}$$

B

$$\frac{8}{5}$$

C

$$\frac{5}{4}$$

D

$$\frac{4}{5}$$

When the axis of load lies in the plane of rivet group, then the most heavily loaded rivet will be the one which (where, Fa is the load shared by each rivet due to axial load and Fm is the shearing load due to moment in any rivet.)

A

Is at the maximum distance from CG of the rivet group

B

Is at the minimum distance from CG of the rivet group

C

Gives the maximum angle between the two forces Fa and Fm

D

Gives the minimum angle between the two forces Fa and Fm

The no-load current drawn by transformer is usually what per cent of the full-load current?

A

0.2 to 0.5 per cent

B

2 to 5 per cent

C

12 to 15 per cent

D

20 to 30 per cent

The maximum efficiency of transformer coupled class A power amplifier is ___________

A

30%

B

50%

C

80%

D

45%

The maximum efficiency of a distribution transformer is

A

at no load

B

at 50% full load

C

at 80% full load

D

at full load

The efficiency of a transformer will be maximum when

A

copper losses = hysteresis losses

B

hysteresis losses = eddy current losses

C

eddy current losses = copper losses

D

copper losses = iron losses

The maximum load that a power transformer can carry is limited by its

A

temperature rise

B

dielectric strength of oil

C

voltage ratio

D

copper loss

An ideal transformer will have maximum efficiency at a load such that

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