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–

The correct answer is 4p and m⁴.

Step 1: Find the power of the combination of lenses
When a number of thin lenses are placed in axial contact with each other, the net power of the combination ($P$) is the algebraic sum of the individual powers of the constituent lenses. If there are four similar lenses, each of power $p$, the total power of the combination is given by:

$P=p_1+p_2+p_3+p_4$

Since the lenses are identical, we substitute $p_1=p_2=p_3=p_4=p$:

$P=p+p+p+p=4p$

Step 2: Find the total magnification of the combination
For a system of lenses placed in contact, the total magnification ($M$) is the product of the individual magnifications of each lens. Since the magnification of each lens is $m$, the total magnification of the combination is:

$M=m_1\times m_2\times m_3\times m_4$

Substituting $m_1=m_2=m_3=m_4=m$:

$M=m\times m\times m\times m=m^4$

Conclusion:
Therefore, the power of the combination is $4p$ and the total magnification is $m^4$.