Question

a convex lens has a foacl lenght of 10 cm at bwhat distance from th lens should an object be placed to form a real image and inverted image 20 cm away from the lens what would the size of the image be if the object is 2 cm high

Answer 1

Answer:

the object should be kept at a distance of 20cm from the lens

Explanation:

this is because if 10cm is the focal length so 2F would be 20cm and if we keep the object at 2f the image is formed at 2f on the other side which is 20 cm as said in the question.

i hope it helps

Answer 2

Answer:

Plz see the image above then the concept would be clearer to u

Answer

1) object distance(u) should be -20cm.(minus 20 cm)

2) Since h(i)=h(o)

so height of image will be 2 cm but bcuz the image is inverted - 2cm ( minus 2 cm)