In a certain camera, a combination of four similar thin convex lenses are arranged axially in contac

Question

In a certain camera, a combination of four similar thin convex lenses are arranged axially in contact. Then the power of the combination and the total magnification in comparison to the power $(p)$ and magnification ( $m$ ) for each lens will be, respectively

Professor PC Thomas Classes · Answer

(a) : For thin lenses in contact, then the powers of each lens add up. \ $ P_t=P_1+P_2+P_3+P_4=4 P $ Given linear magnification of each lens $m$ is The overall magnification of combined lens system is $M=m 	imes m 	imes m 	imes m=m^4$ (dimensionless). Hence the combination has power $4 P$ and magnification $m^4$. $4 P$ and $m^4$ - follows from the additive power law for co-axial lenses and the multiplicative rule for successive magnifications.