IJSO Solutions 1-11-10)

IJSO QUESTION WITHANSWER (1-11-10) 1.

In the diagram if ABC and PQR are equilateral. The CXY equals

(A) 35º (C) 45º

(B*) 40º (D) 50º

Sol.

1

= 3 = 60º = 180  – (65 + 60) = 55 4 = 180  – (75 + 60) = 45 5 = 180  – (55 + 45) = 80 5 = 6 = 80º cxy = 180  – (80 + 60) = 40º 2

2.

A stone of mass m is moved in a circle of radius r with constant speed v. The work doen by the centripetal force over half the circumference circumfer ence of the circle is : (A*) zero (C)

3.

Sol.

mv 2 × 2r r

mv 2 (B) × r r (D) mg × 2r

The most efficient fuel among the following is (A*) methane.

(B) propane.

(C) butane.

(D) pentane.

Methane has the highest percentage of hydrogen. Hence, it burns to give maximum energy.

4.

Adam ’s Apple represents : (A) Arytenoid Arytenoid cartilage of larynx (B) Cricoid cartilage of larynx (C*) Thyroid cartilage of larynx (D) All the above