hce_kmu
110年
物理及化學
第 60 題
For a bi-concave thin lens, the radii of curvature are $10$ and $20\text{ cm}$. If an object is placed $15\text{ cm}$ in front of the mirror, what is the magnification of the image and is it a real or virtual? Upright or inverted? (thin lens’ equation: $1/p+1/q = (n-1)(1/R_1-1/R_2)$, the refractive index of glass is $1.5$).
- A $9.72\text{ cm}$ (virtual behind mirror) and $\text{M} = 0.64$, inverted
- B $11.64\text{ cm}$ (virtual behind mirror) and $\text{M} = 0.58$, inverted
- C $10.91\text{ cm}$ (virtual in front mirror) and $\text{M} = 0.73$, upright
- D $8.69\text{ cm}$ (real in front mirror) and $\text{M} = 0.25$, inverted
- E $12.45\text{ cm}$ (virtual behind mirror) and $\text{M} = 0.53$, upright
思路引導 VIP
請試著回想，當一個透鏡的中心比邊緣還要「薄」時（如雙凹透鏡），光線穿過它之後會向中心匯聚還是向外發散？這種偏折方式所形成的虛像，在位置上會跟物體在同一邊，還是透鏡的另一邊呢？