Question

a diverging lens has a focal length of -14 cm. An object is placed 38 cm from the lens's surface. determine the image distance

Answer 1

• Focal length=-14cm=f
• Object distance=u=38cm
• Image distance=v

Using lens makers formula

`\\ \tt\longmapsto (1)/(v)+(1)/(u)=(1)/(f)`

`\\ \tt\longmapsto (1)/(v)=(1)/(f)-(1)/(u)`

`\\ \tt\longmapsto (1)/(v)=(1)/(-14)-(1)/(38)`

`\\ \tt\longmapsto (1)/(v)=(-19-7)/(266)`

`\\ \tt\longmapsto (1)/(v)=(-26)/(266)`

`\\ \tt\longmapsto v=(266)/(-26)`

`\\ \tt\longmapsto v=(133)/(-13)`

`\\ \tt\longmapsto v=-10.2cm`