NEET
- Exam
- NEET
- Subject
- Physics
- Chapter
- Wave Optics
NEET · Physics · Wave Optics
Given below are two statements: one is labelled as Assertion (A)...
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Two independent monochromatic light bulbs emitting light of the exact same wavelength can be used to produce a sustained interference pattern on a screen.
Reason (R): The phase difference between the light waves emitted by two independent sources changes randomly and rapidly with time.
In the light of the above statements, choose the most appropriate answer from the options given below.
Assertion (A): Two independent monochromatic light bulbs emitting light of the exact same wavelength can be used to produce a sustained interference pattern on a screen.
Reason (R): The phase difference between the light waves emitted by two independent sources changes randomly and rapidly with time.
In the light of the above statements, choose the most appropriate answer from the options given below.
Options
- ABoth Assertion and Reason are true and Reason is the correct explanation of Assertion.
- BBoth Assertion and Reason are true but Reason is not the correct explanation of Assertion.
- CAssertion is true but Reason is false.
- DAssertion is false but Reason is true.
Correct answer
D. Assertion is false but Reason is true.
Step-by-step solution
Assertion (A) is false. For a sustained interference pattern to be formed, the two sources of light must be coherent, meaning they must emit light waves with a constant phase difference. Two independent light bulbs, even if they emit light of the exact same wavelength, are incoherent sources and cannot produce a sustained interference pattern.
Reason (R) is true. In independent light sources, light is emitted by millions of atoms undergoing transitions randomly. As a result, the phase of the emitted light changes abruptly and randomly. Therefore, the phase difference between the waves from two independent sources changes rapidly with time, averaging the interference term to zero over any macroscopic time interval.
Answer: Assertion is false but Reason is true.
Reason (R) is true. In independent light sources, light is emitted by millions of atoms undergoing transitions randomly. As a result, the phase of the emitted light changes abruptly and randomly. Therefore, the phase difference between the waves from two independent sources changes rapidly with time, averaging the interference term to zero over any macroscopic time interval.
Answer: Assertion is false but Reason is true.