1.Which is the most common isotope of uranium found in nature?

2. Radioisotopes are not used in

3. The half-life of a radioactive substance is 4 months. How much time it will take to decay 3/4th of the substance?

4. A team of scientists at Brookhaven National Laboratory including those from India created the heaviest anti-matter (anti-helium nucleus). What is/are the implication/implications of the creation of anti-matter?

1. It will make mineral prospecting and oil exploration easier and cheaper.
2. It will help probe the possibility of the existence of stars and galaxies made of anti-matter.
3. It will help to understand the evolution of the universe.
   Select the correct answer using the codes given below.

5. With reference to the isotopes of elements, consider the following statements
 

A. The isotopes of cobalt are used in the treatment of cancer.
B. The isotopes of iron are used in the diagnosis of anemia.
C. The isotopes of uranium are used as fuel in nuclear reactors.
D. The isotopes of iodine are used in the treatment of Hepatitis A.
Select the correct answer using the codes given below.

6. Consider the following statements.
A. Nuclear fuel is material used in nuclear power stations to produce heat to run turbines.
B. Thorium is used as a nuclear fuel in India.

Which of the above statements is/are correct?

7. The isotope of carbon used in radiocarbon dating is
 

8. Change of water into the vapour is called

9. An example of physical change

10. If an unsaturated sugar solution is prepared by mixing 100 gm of sugar with half-litre of water. Which of the following physical quantities will not change?

11. Which of the following is an example of chemical change?

12. Which of the following is/are the example/ examples of chemical change?

1. Crystallisation of sodium chloride
2. Melting of ice
3. Souring of milk

Select the correct answer using the codes given below.

13. The temperature point at which solid, liquid and gaseous states may stay together is known as
A. boiling point 
B. melting point
C. freezing point
D. triple point
E. None of the above/More than one of the above

14. Detect the odd one.
A. Setting of cement
B. Burning of coal
C. Ripening of fruit
D. More than one of these
E. None of these

15. A substance consisting of two or more ingredients which are not in chemical combination is called