Question

Q.1 Analyse the following observation table showing the variation of image distance (v) with respect to the object distance (u) in case of a convex lens and answer the questions that follow, without doing any calculations:

(A)state the lens formula what is the focal length of the given convex lens?

(B)write the serial number of the observation that is not correct why?

(C)using an appropriate scale draw the ray diagram of the observation serial number 4.

(D)under what condition does a biconvex lens of Glass having a certain refractive index act as a plane glass sheet when immersed in a liquid ?​

Answer 1

Answer:

1.From the observation 3, we can say that Radius of curvature is 40cm so foal length of the convex lens is 20cm.[f=R/2]

2. Observation 6 is incorrect , as the object is in between P and F, the image formed will be virtual image on the same side of object, image distance should be negative.

3.Ray diagram for observation 3: Please refer attachment : object beyond C

4. magnification=m=v/um=30/-60=-1/2= -0.5so the image is real, inverted and diminished.