Lens,Iris and Pupil

Q.

The amount of light entering our eye is controlled by .

1. cornea
2. retina
3. eyelens
4. iris

Q. A thin membrane that covers the front portion of the eye is called .

1. conjunctiva
2. cornea
3. choroid
4. sclera

Q.

Explain how an eye lens changes its focal length. How does it help in seeing near and distant objects?

Q. The pigment retinal is a derivative of _________.

1. vitamin B
2. vitamin D
3. vitamin E
4. vitamin A

Q. The gland is also known as third eye.

1. Thyroid gland
2. Adrenal gland
3. Pineal gland

Q.

The colour of the iris is determined by the presence of _________.

1. lysosome

2. melanin

3. tears

4. photoreceptors

Q.

The adult human eyeball is nearly a ____ structure.

Q.

More the amount of melanin, lighter the colour of the iris.

1. True

2. False

Q. Match the following:
$\begin{array}{cc}\text{Part of eye}& \text{Function}\\ a)\text{Iris}& p)\text{Converts the light into neural signals, and sends}\\ & \text{these signals to the brain for visual recognition}.\\ b)\text{Lens}& q)\text{It bends the light onto the lens.}\\ c)\text{Retina}& r)\text{Controls size of pupil and amount of light reaching}\\ & \text{the retina.}\\ d)\text{Cornea}& s)\text{Focuses light onto the retina and helps the eye to}\\ & \text{focus objects at different distances.}\end{array}$

1. a-r, b-q, c-p, d-s
2. a-r, b-s, c-p, d-q
3. a-p, b-s, c-q, d-r
4. a-r, b-s, c-q, d-p

Q. Which of the following is not a function of the aqueous humour?

1. Provides protection to the eye
2. Provides nourishment to the eye
3. Changes the size of the pupil to regulate light
4. Helps in focusing light onto the retina

Q.

The colour of the iris is determined by the presence of _________.

1. lysosome

2. melanin

3. tears

4. photoreceptors

Q.

Statement 1: The chamber just behind the cornea consists of vitreous humour.

Statement 2: Melanin is present in the choroid layer of the eye.

1. Statement 1 is true but statement 2 is false

2. Statement 1 is false but statement 2 is true

3. Both the statements are true

4. Both the statements are false

Q. A thin membrane that covers the front portion of the eye is called .

1. conjunctiva
2. cornea
3. choroid
4. sclera

Q.

Why our eyes are of different colors?

Q.

Under the condition of dim light, the pupils __________.

1. dilate

2. remain constant

3. constrict

4. dilate then constrict

Q.

Which of the following is differently coloured in different people?

1. Cornea

2. Lens

3. Pupil

4. Iris

Q. Iris regulates the amount of light entering the eye by controlling the size of the _______.

1. pupil
2. cornea
3. sclera
4. choroid

Q. The photoreceptors responsible for the perception of colour are _________.

1. rods
2. cones
3. pupils
4. iris

Q. role of aqueous humor and vitreous humor in our eye??are they connected?

Q. Why are our eyes more sensitive to blue light than yellow light? Is there any special pigment present?

Q.

Which of the following is responsible for focusing light?

1. Lens

2. Ciliary body

3. Ciliary muscle

4. Retina

Q. Which of the following statements is true for a human eye?

1. Iris controls the amount of light entering the eye.
2. Iris helps in changing the focal length of our eye lens.
3. Cornea controls the size of the pupil of the eye.
4. Ciliary muscles change the size of the pupil.

Q.

What is the function of iris?

1. It controls the size of pupil.

2. It controls ciliary muscles.

3. It controls the size of cornea.

4. It focuses light on retina.