NEETPhysicsElectromagnetic Waves
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Microwaves are often referred to as heat waves. Reason (R): Water molecules present in most materials readily absorb infrared waves, increasing their thermal motion and heating the surroundings. In the light of the above statements, choose the most appropriate answer from the options given below:
Options
- ABoth (A) and (R) are true and (R) is the correct explanation of (A)
- BBoth (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
Correct answer
D. (A) is false but (R) is true
Step-by-step solution
Infrared waves are often referred to as heat waves, not microwaves. Therefore, the Assertion (A) is false. The Reason (R) is a true statement according to NCERT. Water molecules (along with other molecules like CO ₂ and NH ₃ ) present in most materials readily absorb infrared waves. After absorption, their thermal motion increases, which causes them to heat up and heat their surroundings. Since (A) is false and (R) is true, the correct option is the fourth one. Answer: (A) is false but (R) is true