Science class 8th Extra marks Questions For Olympiad

1. Which of the following is a non ­metal? 

(A) Mercury 

(B) Magnesium  

(C) Manganese  

(D) None of these.

2. The increase in area of the solid on heating is called 

(A) Superficial expansion  

(B) Linear expansion 

(C) Cubical expansion      

(D) Quadrilateral expansion

3. The temperature at which no more energy can be removed from matter is called 

(A) Absolute zero  

(B) Boiling point 

(C) 32º F  

(D) 32°C

4. A lightning conductor is a 

(A) Piece of metallic wire with spikes through which current can flow

(B) Substance that can be charged by clouds

(C) Carbon rod  

(D) Plastic rod.

5. Which one of the following is true for all chemical reactions? 

(A) There is a change in volume  

(B) Heat is evolved 

(C) Chemical bonds are broken or formed  

(D) There is a change in mass

6. The movement of oxygenated blood from the left auricle to left ventricle and then to aorta to all parts of the body is called 

(A) Extracellular circulation       

(B) Pulmonary circulation 

(C) Systemic circulation            

(D) Intracellular circulation

7. The process of crossing two varieties with different characters to obtain new variety is called 

(A) Introduction  

(B) Selection  

(C) Hybridization  

(D) Conservation

8. Which metal is present in the human body in greater percentage? 

(A) Calcium  

(B) Sodium  

(C) Potassium  

(D) Iron

9. A Brief History of Time is the title of a book written by 

(A)  Albert Einstein          

(B)  Stephen Hawking

(C)  Hendrick Lorentz      

(D)  Isaac Newton

10. Which of the following can produce a virtual image ?

(A)  Plane mirror  

(B)  Concave lens  

(C)  Convex lens  

(D)  All of these

11. When a glass rod is rubbed with a piece of silk cloth

(A)  Both cloth and the rod acquire positive charge

(B)  Rod becomes positively charged while the cloth has a negative charge

(C)  Rod becomes negatively charged while the cloth has a positive charge

(D)  Both cloth and the rod acquire negative charge.

12. A body immersed in a fluid experiencs an upward thrust which depends on

(A)  The weight of the fluid displaced by it 

(B)  The volume of the body 

(C)  The mass of the body  

(D)  All of these.

13. When Cu is exposed to moist air for a long time, which of the following is formed?

(A)  Cu(OH)2  

(B)  CuCO3   

(C)  Both (A) and (B)       

(D)  Cu2O

14. Which of the following statements is true with respect to diamond?

(A)  The carbon atoms are connected to each other by metallic bonds.

(B)  In the diamond crystal, the carbon atoms are very loosely packed.

(C)  Each carbon atom in the crystal is surrounded by four others at the corners of a regular tetrahedron.

(D)  It is a very soft substance.

15. Which of the following is an acute infection of the small intestine caused by a bacterium?

(A)  Cholera 

(B)  Tuberculosis  

(C)  Polio 

(D)  Night blindness

Ans:

1.  (D)   2.  (A)  3.  (A)   4.  (A)  5.  (C)  6.  (C)   7.  (C)  8.  (A)  9.  (B)  10.  (D)  11.  (B)  12.  (A)  13.  (C)  14.  (C)  15.  (A