A ray of light coming parallel to the principal axis after passing through a convex lens, passes through its

Options

A. optical centre
B. focus
C. centre of curvature
D. none of these

Explanation

To solve the question, we need to understand how a convex lens refracts light. Here’s a step-by-step solution:

### Step 1: Understand the Setup
A ray of light is coming parallel to the principal axis of a convex lens. We need to determine where this ray will pass after it refracts through the lens.

**Hint:** Remember that the principal axis is the line that passes through the center of the lens and is perpendicular to its surfaces.

### Step 2: Identify Key Points on the Lens
Identify the important points related to the convex lens:
- **Optical Center (O)**: The central point of the lens where light can pass through without bending.
- **Focus (F)**: The point where parallel rays of light converge after passing through the lens.
- **Center of Curvature (C)**: The center of the sphere from which the lens is made.

**Hint:** The focus is located on the principal axis at a distance equal to the focal length from the optical center.

### Step 3: Draw the Ray Diagram
Draw a ray diagram to visualize the situation:
1. Draw the convex lens with the principal axis.
2. Draw a ray of light parallel to the principal axis approaching the lens.
3. After passing through the lens, show the ray bending towards the focus.

**Hint:** Use a straight line for the incoming ray and a curved line for the refracted ray to illustrate the bending of light.

### Step 4: Analyze the Path of the Ray
When the ray of light passes through the convex lens:
- The ray that comes in parallel to the principal axis will refract and pass through the focus (F) on the opposite side of the lens.

**Hint:** The bending of light occurs due to the change in speed as it moves from air into the lens material.

### Step 5: Conclusion
The ray of light that comes parallel to the principal axis after passing through a convex lens will pass through the focus of the lens.

**Final Answer:** The correct option is the focus (F).

---