To determine the modulus of rupture, the size of test specimen used is A. 150 x 150 x 500 mm B. 100 x 100 x 700 mm C. 150 x 150 x 700 mm D. 100 x 100 x 500 mm

The correct answer is A. 150 x 150 x 500 mm.

The modulus of rupture is a measure of the ability of a material to resist breaking when subjected to a bending load. It is calculated by dividing the maximum load applied to a test specimen by the area of the specimen’s cross-section.

The size of the test specimen used to determine the modulus of rupture is important because it affects the accuracy of the results. The larger the specimen, the more accurate the results will be. However, larger specimens are also more difficult to test.

The standard size of test specimen used to determine the modulus of rupture is 150 x 150 x 500 mm. This size is large enough to provide accurate results, but it is also small enough to be easily tested.

Options B and C are not the standard size of test specimen used to determine the modulus of rupture. Option D is too small to provide accurate results.