Kerala SSLC · Biology · Class 10

Windows of Knowledge: Important Questions with Answers

These are 10 important multiple-choice questions from the Kerala SSLC Biology chapter “Windows of Knowledge” (Kerala SCERT syllabus). Each one shows the correct answer and a short explanation of why it is right. Try answering before you read the answer. ExamSummary has 10 practice questions on this chapter in total.

  1. Q1.In the human eye, which structure is responsible for focusing light rays onto the retina?

    • A)Cornea
    • B)Lens
    • C)Iris
    • D)Pupil

    Answer: B) Lens

    The lens is a flexible structure that changes its shape to focus light rays precisely on the retina. While the cornea helps in initial refraction, the lens provides the main adjustment needed for clear vision.

  2. Q2.What is the primary function of the rods and cones present in the retina?

    • A)To regulate the amount of light entering the eye
    • B)To convert light energy into electrical nerve impulses
    • C)To maintain the shape of the eyeball
    • D)To produce tears for lubrication

    Answer: B) To convert light energy into electrical nerve impulses

    Rods and cones are photoreceptor cells that detect light and color. They convert this light energy into electrical signals that are sent to the brain via the optic nerve for visual processing.

  3. Q3.Which defect of vision is corrected using a concave lens?

    • A)Hypermetropia
    • B)Presbyopia
    • C)Myopia
    • D)Astigmatism

    Answer: C) Myopia

    Myopia, or nearsightedness, occurs when light focuses in front of the retina. A concave lens diverges the incoming light rays so that the image forms correctly on the retina.

  4. Q4.The ability of the eye lens to change its focal length is known as:

    • A)Dispersion
    • B)Accommodation
    • C)Refraction
    • D)Persistence

    Answer: B) Accommodation

    Accommodation is the process by which the ciliary muscles adjust the curvature of the lens to focus on objects at varying distances. This allows the eye to see both nearby and faraway objects clearly.

  5. Q5.In the chapter 'The Eye and the Colorful World', what causes the dispersion of white light into seven colors?

    • A)Reflection from a mirror
    • B)Refraction through a prism
    • C)Absorption by the retina
    • D)Diffusion in the atmosphere

    Answer: B) Refraction through a prism

    When white light passes through a glass prism, it refracts at different angles depending on the wavelength. This separation of colors is called dispersion, resulting in the visible spectrum.

  6. Q6.Where does the image form in a hypermetropic (long-sighted) eye without correction?

    • A)On the retina
    • B)In front of the retina
    • C)Behind the retina
    • D)At the blind spot

    Answer: C) Behind the retina

    In hypermetropia, the eyeball is too short or the lens has insufficient power, causing the image to form behind the retina. This makes nearby objects appear blurry.

  7. Q7.Which part of the eye controls the diameter of the pupil to regulate light entry?

    • A)Cornea
    • B)Iris
    • C)Optic Nerve
    • D)Vitreous Humor

    Answer: B) Iris

    The iris is the colored muscular ring surrounding the pupil. It contracts or relaxes to change the pupil's size, thereby controlling the amount of light entering the eye.

  8. Q8.Why can we not see anything immediately after entering a dark room from bright sunlight?

    • A)The lens becomes permanently deformed
    • B)The retina needs time to adapt to low light levels
    • C)The cornea closes temporarily
    • D)The optic nerve stops functioning

    Answer: B) The retina needs time to adapt to low light levels

    The photoreceptors (rods) take time to regenerate the pigment rhodopsin in low light conditions. Until adaptation occurs, the sensitivity of the eye remains low, causing temporary blindness.

  9. Q9.The blind spot in the human eye is located at the region where:

    • A)The lens meets the cornea
    • B)The optic nerve exits the retina
    • C)The pupil is widest
    • D)The ciliary muscles attach

    Answer: B) The optic nerve exits the retina

    The blind spot is the point where the optic nerve leaves the eye. There are no photoreceptor cells (rods or cones) at this location, so no image is detected here.

  10. Q10.If a person sees distant objects clearly but nearby objects are blurred, they likely suffer from:

    • A)Myopia
    • B)Hypermetropia
    • C)Cataract
    • D)Glaucoma

    Answer: B) Hypermetropia

    This condition is known as Hypermetropia or farsightedness. The eye focuses images behind the retina, making close-up details difficult to perceive without corrective convex lenses.

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