IJSO Solutions.

IJSO QUESTION WITHANSWER 1.

The sum of the reciprocals of the roots of the equation, (A)  –

Sol.

2010 2009

(B*)  – 1

(C)

2009 1 x+1+ = 0, is 2010 x

2009 2010

(D) 1

2009 x 1 +1+ =0 2010 x

2009 x 2  2010 x  2010 =0 2010 x 2009x2 + 2010x + 2010 = 0 +=

 =

 –2010 2009

2010 2009

 –2010 1     2009 1 + = 2010 =  –    2009 2.

1

The quality of a tone : (A) Decreases with loudness (B) Varies directly as pitch (C*) Depends on the overtones that are present there (D) Varies inversely as the frequency

3.

Among the pair of compounds, the one that illustrates the law of multiple proportion is (A) Na NaCl and NaBr.

Sol.

(B) NH NH3 and NCl3.

(C*) CuO and Cu2O.

(D) H2O and D2O.

According to law of multiple proportion, if two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element, are in the ratio of small whole numbers. Here, copper and oxygen are two elements which combine to form two different oxides of formula CuO and Cu2O

4.

Mitotic anaphase differs from metaphase in possessing (A) Same number of chromosomes and same s ame number of chromatids (B) Half number of chromosomes and half number of chromatids (C) Half number of chromosomes and same number of chromatids (D*) Same number of chromosomes and half number of chromatids.