Question

In the following questions, a statement of assertion followed by the reason is given. Choose the correct answers out of the following choices:

Assertion: Speed of wave = $\frac{wavelength}{timeperiod}$.

Reason: Wavelength is the distance between two nearest particles in phase.

• A. Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.
• B. The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.
• C. Assertion is true but the Reason is false.
• D. The statement of the Assertion is false but the Reason is true.
• E. Both the statements are false.

Answer 1

The correct option is B

The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.

1. Wavelength- The distance traveled by the wave in one time period is called wavelength.
2. It is also defined as the distance between any two consecutive crests or consecutive troughs.
3. These two points which are in the same phase are at a distance equal to the wavelength of the wave.
4. If the wave velocity is $v$, frequency is $f$, the wavelength is $\lambda$ and $T$ is the time period.
5. $Wavelength=wavevelocity\times Timeperiod$ $i.e.,\lambda =v\times T$
6. So, $v=\frac{\lambda }{T}$$=\frac{wavelength}{timeperiod}$.
7. Thus, Both the statements are true but Reason is not the correct explanation of the Assertion.
8. Hence, the correct answer is B.