To determine the approximate value of the focal length of a given concave mirror, you focus the image of a distant object formed by the mirror on a screen. The image obtained on the screen, as compared to the object is always:

Options

A. Laterally inverted and diminished
B. Inverted and diminished
C. Erect and diminished
D. Erect and highly diminished

Explanation

To determine the approximate value of the focal length of a given concave mirror using a distant object, we can analyze the characteristics of the image formed by the mirror. Here’s a step-by-step solution:

### Step 1: Understand the properties of a concave mirror
Concave mirrors have the property of converging light rays that are parallel to the principal axis. When a distant object is placed in front of a concave mirror, the light rays coming from the object are considered to be parallel.

**Hint:** Remember that parallel rays converge at the focal point of a concave mirror.

### Step 2: Identify the nature of the image formed
When the parallel rays from a distant object strike the concave mirror, they reflect and converge at a point. This point is the focus of the mirror. The image formed by a concave mirror for a distant object is located at the focal point.

**Hint:** The image of a distant object is formed at the focus of the mirror.

### Step 3: Determine the characteristics of the image
The image formed by a concave mirror is real, inverted, and diminished when the object is at a distance (considered to be at infinity). This means that the image will be smaller than the object and flipped upside down.

**Hint:** Recall that real images formed by concave mirrors are always inverted and can be smaller than the object.

### Step 4: Conclude the nature of the image
Based on the above analysis, the image obtained on the screen, as compared to the object, is always inverted and diminished.

**Hint:** Focus on the terms "inverted" and "diminished" when describing the image characteristics.

### Final Answer
The image obtained on the screen, as compared to the object, is always **inverted and diminished**.