364529 A convex lens of focal length \(40\;\,cm\) forms an image of an extended source of light on a photoelectric cell. A current \(I\) is produced. The lens is replaced by another convex lens having the same diameter but focal length \(20\;\,cm\). The photoelectric current now is :
364529 A convex lens of focal length \(40\;\,cm\) forms an image of an extended source of light on a photoelectric cell. A current \(I\) is produced. The lens is replaced by another convex lens having the same diameter but focal length \(20\;\,cm\). The photoelectric current now is :
364529 A convex lens of focal length \(40\;\,cm\) forms an image of an extended source of light on a photoelectric cell. A current \(I\) is produced. The lens is replaced by another convex lens having the same diameter but focal length \(20\;\,cm\). The photoelectric current now is :
364529 A convex lens of focal length \(40\;\,cm\) forms an image of an extended source of light on a photoelectric cell. A current \(I\) is produced. The lens is replaced by another convex lens having the same diameter but focal length \(20\;\,cm\). The photoelectric current now is :
364529 A convex lens of focal length \(40\;\,cm\) forms an image of an extended source of light on a photoelectric cell. A current \(I\) is produced. The lens is replaced by another convex lens having the same diameter but focal length \(20\;\,cm\). The photoelectric current now is :