Question

An air bubble is trapped at point P (CP = 1.75 cm) in a spherical glass ball (n = 1.5) of radius 7 cm as shown in the figure. Find the nature and position of the image when viewed from side B. Show the image formation by drawing a ray diagram.

Hint:

When an object is placed inside a spherical surface, the image formed by the curved surface may be real and inverted depending on the object's distance from the center of the sphere. In this case, the negative sign indicates a real image formed on the opposite side.

Answer 1

For light moving from a denser to a rarer medium: \[ \frac{n_2}{-u} + \frac{n_1}{v} = \frac{n_1 - n_2}{R} \] Substituting the provided values: \[ \frac{1.5}{8.75} + \frac{1}{v} = \frac{(1.5 - 1)}{-7} \] The equation simplifies to: \[ \frac{1}{v} = \frac{0.5}{7} - \frac{1.5}{8.75} \] \[ \frac{1}{v} = -\frac{1}{10} \] Therefore: \[ v = -10 \, \text{cm} \] The image formed is virtual.