Final answer:
To calculate the power of a converging lens and diverging lens combination, we add their powers, with the diverging lens having negative power. The correct formula for the combined power is 1/f1 - 1/f2, resulting in a converging combination when f1 is greater than f2. The correct answer is b. Power = 1f1−1/f2, Diverging.
Step-by-step explanation:
The student has asked about the power and nature of a combination of a converging lens and a diverging lens. To find the total power of this combination, we add the powers of the individual lenses where the power of a lens (P) is the inverse of its focal length (f), given by P = 1/f.
Since the power of a diverging lens is negative, the formula for the combined power is P = P1 + P2 = 1/f1 + 1/(-f2) = 1/f1 - 1/f2.
This combination could result in a converging or diverging effect depending on the magnitudes of f1 and f2. However, because the problem states that f1 is greater than f2, this combination will be converging. Therefore, the correct answer is b: Power = 1/f1 - 1/f2, Converging.