281. Assertion (A) : The composition of the lowest layer of the atmosphere remains relatively constant.
     Reason (R) : There is intensive mixing and circulation in the lower layers of the atmosphere.

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

   
   
   

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

   
   
   

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

   
   
   

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

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

---

282. Assertion (A) : Only a minute portion of solar radiation is intercepted by the earth.
     Reason (R) : Other planets are obstructing the path of sun ray's

1. 1. Both (A) and (R) are correct and (R) explains (A)

   
   
   

   2. Both (A) and (R) are correct but (R) does not explain (A)

   
   
   

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

   
   
   

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

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

---

---

283. Consider the following statements.
     1. Ozone is found mostly in the Stratosphere.
     2. Ozone layer lies 55-75 km above the surface of the earth.
     3. Ozone absorbs ultraviolet radiation from the Sun.
     4. Ozone layer has no significance for life on the earth.
     Which of the above statements are correct ?

1. 1. 1 and 3

   
   
   

   2. 2 and 4

   
   
   

   3. 2 and 3

   
   
   

   4. 1 and 4

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

---

284. Which one of the following statements related to both land and sea breezes are true ?

1. 1. Air blows from the sea to the land during the day.

   
   
   

   2. Air blows from the land to the sea during the night

   
   
   

   3. Air generally moves from a cool region to a warmer region

   
   
   

   4. The lands cool more quickly than the sea during the night

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

---

---

285. Assertion (A) : The atmosphere receives most of the heat only indirectly from the sun and directly from the earth's surface.
     Reason (R) : The conversion from short wave solar to long wave terrestrial energy takes place at the earth's surface.

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

   
   
   

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

   
   
   

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

   
   
   

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

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

---