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QJEEM23Ph2f85: JEE Main 2023 Physics - Class 12 JEEM23Ph2f85 Solution: A fish rising vertically upward with a uniform velocity of ,…

A fish rising vertically upward with a uniform velocity of 8 ms−18 \mathrm{~ms}^{-1} , observes that a bird is diving vertically downward towards the fish with the velocity of 12 ms−112 \mathrm{~ms}^{-1} . If the refractive index of water is 43\frac{4}{3} , then the actual velocity of the diving bird to pick the fish, will be __________ ms−1\mathrm{ms}^{-1} .

Step-by-Step Verified Solution

The bird's diving velocity is given relative to the fish. In order to find the actual velocity of the bird, we need to consider the refractive index of the water.

The fish sees the bird diving with a velocity of 12 m/s12 \ \text{m/s} . We can write the equation considering the velocities relative to the fish:

Vb/f43=−843+−v1\frac{V_{\text{b/f}}}{\frac{4}{3}} = \frac{-8}{\frac{4}{3}} + \frac{-v}{1}

Here, Vb/fV_{\text{b/f}} is the bird's diving velocity relative to the fish, and vv is the actual velocity of the bird.

Now, let's solve for vv :

−1243=−843−v\frac{-12}{\frac{4}{3}} = \frac{-8}{\frac{4}{3}} - v

v=3 m/sv = 3 \ \text{m/s}

So, the actual velocity of the diving bird to pick the fish relative to the fish is 3 m/s3 \ \text{m/s} .

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