Read the assertion and reason carefully, and choose the correct answer:
  
1. Assertion (A) : Generally, lightning is seen earlier, and thunder is heard later.
Reason (R) : Speed of the light is less than the speed of sound.
 
 
2. Assertion (A) : The change in air pressure affects the speed of sound.
Reason (R) : The speed of sound in a gas is inversely proportional to the square of the pressure.