Select the correct answer to these questions from the codes : (a), (b), (c) & (d)
a) Both Assertion (A) and Reason (R) are true and reason (R) is the correct explanation of A.
b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
c) Assertion (A) is true but Reason (R) is false.
d) Assertion (A) is false and Reason (R) is also false.
Assertion (A) : The focal length of lens does not change when red light is replaced by blue light.
Reason (R) The focal length of lens does not depends on colour of light used.
Doubt by Angad
Solution :
As per the Lens Makers Formula, the focal length depends on refractive index which in turns depends on wavelength of light. Hence, the focal length of lens does change when red light is replaced by blue light. So we can say that focal length of the lens depend on the colour of light used.
The correct answer is d) Assertion (A) is false and Reason (R) is also false.
