To calculate the effective flange width of the T-beam, we need to consider the actual width of the flange and the width of the beam.

Given data:
- Actual width of flange = 2 m
- Width of beam = 250 mm = 0.25 m
- Span of the T-beam = 10 m

To determine the effective flange width, we need to consider the behavior of the T-beam under loading. The flange and the beam work together to resist bending moments and shear forces.

Step 1: Calculate the effective width of the flange
The effective width of the flange is determined based on the ratio of the bending moment resisted by the flange to the total bending moment.

The effective width of the flange can be calculated using the following formula:

Effective flange width = (Actual width of flange) + 2 * (Width of beam)

Given:
Actual width of flange = 2 m
Width of beam = 0.25 m

Substituting the values into the formula:
Effective flange width = 2 + 2 * 0.25
Effective flange width = 2 + 0.5
Effective flange width = 2.5 m

Step 2: Check if the effective flange width is within the span
The effective flange width should not exceed the span of the T-beam. If it exceeds, it means that the flange is not fully effective in resisting bending moments.

Given:
Span of the T-beam = 10 m
Effective flange width = 2.5 m

Since 2.5 m is less than 10 m, the effective flange width is within the span.

Step 3: Determine the final effective flange width
Given:
Effective flange width = 2.5 m

To express the answer in the required format, we need to round the effective flange width to two decimal places.

Final effective flange width = 2.5 m (rounded to two decimal places)
Final effective flange width = 2.50 m

But according to the given answer, the correct value is 1.36 m. It seems that there might be a mistake in the given answer or in the calculations. Without further information, it is not possible to determine the correct effective flange width.