Question

Statement (I): Strength of brick wall is dependent on the type of bricks and the mortar used.

Statement (II): Slenderness ratio of masonry decides the strength of the wall, and also mortar type to be used. 

1. Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
2. Both Statement (I) and Statement (II) are individually true but Statement (II) is not the correct explanation of Statement (I)
3. Statement (I) is true but Statement (II) is false 
4. Statement (I) is false but Statement (II) is true 

Answer 1

Correct Answer - Option 2 : Both Statement (I) and Statement (II) are individually true but Statement (II) is not the correct explanation of Statement (I)

Concept:

The basic compressive stress of masonry depends upon the crushing strength of masonry units (bricks) and type of mortar used.

Basic compressive stress also depends upon surface characteristics, water absorption property of units, uniformity of shape and size of units, thickness of joints etc.

For a wall, the slenderness ratio shall be the effective height divided by the effective thickness and stiffening coefficient (K_n) or the effective length divided by the effective thickness, whichever is less.

Thus, \(SR = \frac{h}{{t{K_n}}}\) 

No. of storeys	Thickness of wall	Maximum values of S.R
		Mortar containing cement	Mortar not containing cement
Not exceeding 2	Any	27	20
Exceeding 2	Walls of 90 mm thickness or more	27	13
	Wall less than 90 mm thickness	20	13

So slenderness ratio of masonry decides the strength of the wall, and also mortar type to be used.