In the following question, the sentence given with blank to be filled in with an appropriate word. Select the correct alternative out of the four and indicate it by selecting the appropriate option.
In the following question, out of the four alternatives, select the alternative which best expresses the meaning of the idiom/Phrase. To put a spoke in one's wheel
Find the power of a convex lens if the image formed is at a distance of 20 cm from the lens when the object is placed on the other side of the lens at 25 cm from the optical centre?