Punya Daya Tahan Lebih, Power Amplifier Hertz HMP 4D Jadi

power 4dThe power of a lens is +4D. Find the focal length of this lens. An object is placed at a distance of 50 cm from the optical centre of this lens. State the natureTwo lenses have power of (i) + 2 d (ii) -4D. What is the nature and focal length of each lens? b. An object is kept at a distance of 100 cm from lens of power -4D. Calculate the image distance.