Question

Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R.  
Assertion A : EM waves used for optical communication have longer wavelengths than that of microwave, employed in Radar technology.  
Reason R : Infrared EM waves are more energetic than microwaves, (used in Radar)  
In the light of given statements, choose the correct answer from the options given below:  

• A. Both A and R true and r is the correct explanation of A
• B. Both A and R 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

Answer 1

The Correct Option is D

Optical communication is performed in the frequency range of 1 THz to 1000 THz (from Microwave to UV). Therefore, the wavelength of EM waves used for optical communication is shorter than that of microwaves used in Radar. Hence, Assertion A is incorrect. On the other hand, Reason R is true because infrared waves have higher frequency and energy compared to microwaves. Thus, Assertion A is false but Reason R is true. Therefore, the correct answer is \( \boxed{1} \).