Ch.30 – Assertion and reason :- Exercise 1

Directions : Choose the correct alternatives from the following options as given below for the Assertion (A) and Reason (R), given in each of the questions.

(a) Both (A) and (R) are true and (R) is the correct explanation of A.

(b) Both (A) and (R) are true but (R) is not the correct explanation of (A).

(c) (A) is true but (R) is false.

(d) (A) is false but (R) is true.

(e) Both (A) and (R) are false.

1. Assertion (A): When common salt is kept open, it absorbs moisture from the air.

Reason (R): Common salt contains magnesium chloride.

Answer & Solution

2. Assertion (A): The steam engine was invented by James Watt.

Reason (R) : There was a problem of taking out -, water from flooded mines.

Answer & Solution

3. Assertion (A) : We prefer to wear white clothes in winter.

     Reason (R) : White clothes are good reflectors of heat.

Answer & Solution

4. Assertion (A): Earthworms are not good for agriculture.

    Reason (R) : Earthworms break down the soil into fine particles and make it soft.

Answer & Solution

5. Assertion (A) : Mercury is the farthest planet from the sun.

    Reason (R): Mercury is the smallest planet in the entire solar-system .

Answer & Solution

6. Assertion (A): Red green colour blindness 0ccurs with more frequency in males than in females.

    Reason (R) : Females have two chromosomes and males have one .

Answer & Solution

7. Assertion (A): Indus Valley people knew the art of navigation.

    Reason (R) : Indus Valley seals indicate prevalence of overseas trade.

Answer & Solution

8. Assertion (A) : A person with blood group 0 positive is supposed to be a universal recipient.

    Reason (R) : The blood type 0 positive does not contain any antigens.

Answer & Solution

9. Assertion (A) : Noise pollution is an unwanted accumulation of noise in the atmosphere.

    Reason (R) : It interferes with the communication.

Answer & Solution

10. Assertion (A) : Akbar found Din-e-Illahi

      Reason (R) : He was motivated by self glorification.

Answer & Solution

11. Assertion (A): Safety fuses are made up of materials having a high melting point.

     Reason (R) : Safety fuses should be resistant to electric current.

Answer & Solution

12. Assertion (A) : Milk production in India is low as compared to other countries of the world.

       Reason (R) : The animal rearers in India are poor.

Answer & Solution

13. Assertion (A): Sprouting should not be done before consuming the grains.

       Reason (R) : Sprouting kills many vital vitamins.

Answer & Solution

14. Assertion (A) : The Goitre is a common disease in mountainous regions.

       Reason (R) : The diet of the people in mountains lacks content.

Answer & Solution

15. Assertion (A): Roughaes prevents constipation.

      Reason (R) : Roughaes add bulk to the food.

Answer & Solution

16. Assertion (A): Diamond is used for cutting glass.

      Reason (R) : Diamond has a high refractive index.

Answer & Solution

17. Assertion (A): India is a democratic country.

      Reason (R) : India has a Constitution of its own.

Answer & Solution

18. Assertion (A) : Neptune is the coldest planet.

      Reason (R) : It receives slanting rays of the sun.

Answer & Solution

19. Assertion (A): Food materials should not be soaked in water for a long time.

       Reason (R) : Washing leads to loss of vitamin A and vitamin D from the foodstuff.

Answer & Solution

20. Assertion (A) : Water kept in earthen pots gets cooled in summer.

       Reason (R) : Evaporation causes cooling.

Answer & Solution

21. Assertion (A): In the upper courses, the main work of the river is erosion.

      Reason (R) : River flows swiftly in their upper courses.

Answer & Solution

22. Assertion (A): Most of the ancient civilisations grew near the rivers.

Reason (R) : The main occupation of man was agriculture.

Answer & Solution

23. Assertion (A) : Telephone wires sag more in summer.

Reason (R) : They expand due to summer heat.

Answer & Solution

24. Assertion (A) : The body of the shes is streamlined.

       Reason (R) : The streamlined body helps the fish to cut its way through the water.

Answer & Solution

25. Assertion (A): Seeds should be treated with fungicide solution.

Reason (R): Seeds do not germinate, unless treated with fungicide solution.

Answer & Solution

 Directions for Q. No. 26 to 30: Each of the question below has a set of Assertion (A) and Reason (R). Mark your answer as:

(a) if both A and R are true and R is the correct explanation of A

(b) A is true but R is false

(c) if both A and R are true but R is not the correct explanation of A .

(d) A is false but R is true

26. Assertion (A): India has a tropical monsoon type climate.

Reason (R): India is located exactly between the tropical latitudes.

Answer & Solution

27. Assertion (A): For the production of aluminium, cheap electricity is essential.

Reason (R): Extraction of aluminium from its ore requires abundant supply of electricity.

Answer & Solution

28. Assertion (A) : Winds are deflected to their right in Northern Hemisphere and to the left in the Southern                                                  Hemisphere.

Reason (R) : Rotation of earth causes the changes in wind direction.

Answer & Solution

29. Assertion (A): Noise pollution is an unwanted accumulation of noise in the atmosphere.

Reason (R) : It interferes with communication.

Answer & Solution

30. Assertion (A) : Forest cutting is undesirable from the point of view of soil erosion.

Reason (R) : Cutting of forests reduces the percolation of rain water

Answer & Solution