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A real object is placed infront of a convex mirror (focal length f). It moves towards the mirror, the image also moves. If `V_(i)=` speed of image and `V_(0)=` speed of the object and u is the distance of object from mirror along principal axis, then

A

`V_(i) lt V_(0)` if `|u| lt |f|`

B

`V_(i) gt V_(0)` if `|u| gt |f|`

C

`V_(i) lt V_(0)` if `|u|gt|f|`

D

`V_(i)=V_(0)` if `|u|=|f|`

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The correct Answer is:
To solve the problem, we need to analyze the behavior of the image formed by a convex mirror when a real object moves towards it. We will use the mirror formula and the concept of magnification to derive the relationship between the speeds of the object and the image. ### Step-by-Step Solution: 1. **Understanding the Mirror Formula**: The mirror formula for a convex mirror is given by: \[ \frac{1}{f} = \frac{1}{v} + \frac{1}{u} \] where: - \( f \) is the focal length of the convex mirror (positive for convex mirrors), - \( v \) is the image distance (negative for virtual images formed by convex mirrors), - \( u \) is the object distance (negative as per the sign convention). 2. **Differentiating the Mirror Formula**: To find the relationship between the speeds of the object and the image, we differentiate the mirror formula with respect to time \( t \): \[ 0 = -\frac{1}{v^2} \frac{dv}{dt} - \frac{1}{u^2} \frac{du}{dt} \] Here, \( \frac{du}{dt} \) is the speed of the object \( V_0 \) (which is negative since the object is moving towards the mirror), and \( \frac{dv}{dt} \) is the speed of the image \( V_i \) (which is also negative since the image moves towards the mirror). 3. **Rearranging the Equation**: Rearranging the differentiated equation gives: \[ \frac{dv}{dt} = -\frac{u^2}{v^2} \frac{du}{dt} \] Substituting \( V_0 = \frac{du}{dt} \) and \( V_i = \frac{dv}{dt} \): \[ V_i = -\frac{u^2}{v^2} V_0 \] 4. **Analyzing the Relationship**: Since \( u \) is the distance of the object from the mirror (which is negative) and \( v \) is the image distance (also negative), the magnitudes can be considered. The image distance \( v \) is always less than the object distance \( u \) for a convex mirror, leading to: \[ |V_i| < |V_0| \] This implies that the speed of the image \( V_i \) is less than the speed of the object \( V_0 \). 5. **Conclusion**: Therefore, we conclude that the speed of the image is always less than the speed of the object when the object is moving towards the convex mirror. ### Final Answer: The correct options are: - The speed of the image \( V_i \) is less than the speed of the object \( V_0 \).

To solve the problem, we need to analyze the behavior of the image formed by a convex mirror when a real object moves towards it. We will use the mirror formula and the concept of magnification to derive the relationship between the speeds of the object and the image. ### Step-by-Step Solution: 1. **Understanding the Mirror Formula**: The mirror formula for a convex mirror is given by: \[ \frac{1}{f} = \frac{1}{v} + \frac{1}{u} ...
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