Consider the following statements about the nerve cells found in the retina: 1. Cones are sensitive to bright light. 2. Rods are sensitive to bright light only. 3. Rods are responsible for sensing colour. Which of the statements given above is/are correct?

The correct option is (a). Explanation The human eye functions as an optical instrument where the retina acts as the light-sensitive screen. The retina contains two primary types of photoreceptor cells-rods and cones-which convert light energy into electrical signals sent to the brain via the optic nerve. Statement-wise Analysis - Statement 1 is Correct: Cones are photoreceptor cells responsible for photopic vision (daylight vision). They are less sensitive to light than rods and require bright light to function effectively. They enable high visual acuity and color perception. - Statement 2 is Incorrect: Rods are responsible for scotopic vision (twilight or dim light vision). They are highly sensitive to light and allow vision in low-light conditions. They do not function in bright light due to the saturation of their pigment, rhodopsin. - Statement 3 is Incorrect: Rods are not capable of distinguishing colors; they provide monochromatic (black and white) vision. Color sensing is the specific function of cones, which exist in three types sensitive to different wavelengths (red, green, and blue). Key Takeaway Rods are essential for vision in dim light (night vision) and do not detect color. Cones are essential for vision in bright light and are responsible for color differentiation.

Consider the following statements about the nerve cells found… - NCERT Class 8 Science MCQ

NCERT Class 8 Science — Chapter 4: Light

mcqmedium

Consider the following statements about the nerve cells found in the retina:

Cones are sensitive to bright light.
Rods are sensitive to bright light only.
Rods are responsible for sensing colour.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Science - class 8 · Page 172

Options

A1 only
B2 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (a).

Explanation

The human eye functions as an optical instrument where the retina acts as the light-sensitive screen. The retina contains two primary types of photoreceptor cells-rods and cones-which convert light energy into electrical signals sent to the brain via the optic nerve.

Statement-wise Analysis

Statement 1 is Correct: Cones are photoreceptor cells responsible for photopic vision (daylight vision). They are less sensitive to light than rods and require bright light to function effectively. They enable high visual acuity and color perception.
Statement 2 is Incorrect: Rods are responsible for scotopic vision (twilight or dim light vision). They are highly sensitive to light and allow vision in low-light conditions. They do not function in bright light due to the saturation of their pigment, rhodopsin.
Statement 3 is Incorrect: Rods are not capable of distinguishing colors; they provide monochromatic (black and white) vision. Color sensing is the specific function of cones, which exist in three types sensitive to different wavelengths (red, green, and blue).

Key Takeaway

Rods are essential for vision in dim light (night vision) and do not detect color. Cones are essential for vision in bright light and are responsible for color differentiation.

Your note

More from Chapter 4: Light

With reference to the Periscope, consider the following statements: 1. It works on the principle of multiple reflections. 2. It uses two plane mirrors arranged at right angles to each other. 3. It allows viewing of objects that are not directly in the line of sight. Which of the statements given above are correct?

medium

With reference to image formation by a plane mirror, consider the following statements: 1. The image formed cannot be obtained on a screen. 2. The image appears at a greater distance behind the mirror than the object is in front. 3. The image undergoes lateral inversion. Which of the statements given above are correct?

medium

Consider the following statements about the image formed by a plane mirror: 1. It is inverted vertically. 2. It is of the same size as the object. 3. It appears to be at the same distance behind the mirror as the object is in front. Which of the statements given above is/are correct?

easy

In the context of the reflection of light, what does the term 'angle of incidence' refer to?

easy

With reference to the eye's ability to see, consider the following statements: 1. A normal eye can clearly see distant objects as well as objects nearby. 2. The minimum distance for distinct vision is constant at 50 cm for all ages. 3. In old age, eyesight may become foggy due to the eye lens becoming cloudy. Which of the statements given above is/are correct?

medium

Keep practising Chapter 4: Light

Work through every question from this NCERT chapter.

Browse all NCERT Class 8 Science chapters