Question

An object is located 360 millimeters from a converging lens. The image formed is 150 millimeters high, at a distance of 90 millimeters from the lens. What’s the height of the object?

Answer 1

The height of the object : 600 mm

Further explanation

Given

d object=360 mm(object distance)

d image=90 mm(image distance)

Required

h object

Solution

focal length = f :

`\tt (1)/(f)=(1)/(d_o)+(1)/(d_i)\\\\(1)/(f)=(1)/(360)+(1)/(90)\rightarrow f=72~mm`

The magnification :

`\tt M=(d_i)/(d_o)=(90)/(360)=0.25`

`\tt M=(h_i)/(h_o)\\\\0.25=(150)/(h_o)\rightarrow h_o=600~mm`