Assertion (A): The focal length of a lens doe | vedclass

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(D) The focal length $f$ of a lens is given by the Lens Maker's Formula: $\frac{1}{f} = (\mu - 1) \left( \frac{1}{R_1} - \frac{1}{R_2} \right)$.Accord

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Both $A$ and $R$ are false

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(D) The focal length $f$ of a lens is given by the Lens Maker's Formula: $\frac{1}{f} = (\mu - 1) \left( \frac{1}{R_1} - \frac{1}{R_2} \right)$.According to Cauchy's equation,the refractive index $\mu$ of a material depends on the wavelength $\lambda$ of light,where $\mu$ increases as $\lambda$ decreases.Since the wavelength of blue light is shorter than that of red light,the refractive index for blue light is greater than that for red light $(\mu_{blue} > \mu_{red})$.Consequently,the focal length $f$ decreases when red light is replaced by blue light.Therefore,the assertion $(A)$ is false and the reason $(R)$ is also false.

$Assertion (A)$: The focal length of a lens does not change when red light is replaced by blue light.
$Reason (R)$: The focal length of a lens does not depend on the colour of the light used.

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$Assertion (A)$: The focal length of a lens does not change when red light is replaced by blue light.$Reason (R)$: The focal length of a lens does not depend on the colour of the light used.