C-05 — Light for Sight

Which one is a special use of mirrors discussed in the chapter?

How many side view mirrors are usually used on a car?

Where are the side view mirrors of a car placed?

Where is the rear-view mirror placed inside a car?

What is the main benefit of side view and rear-view mirrors for a driver?

Before starting the car, what must a driver do with the mirrors?

Why must the mirrors of a car be cleaned properly?

When moving the car backward, the driver should look at the mirrors —

Hilly roads are usually built in which pattern?

At what angle does the next part of the road often turn at a blind turn on a hilly road?

What is placed on stands at the blind turns of hilly roads to make driving safe?

The viewing mirrors of a car are actually —

Why are convex mirrors used as side view mirrors in cars?

In a transparent homogeneous medium light always travels in —

Refraction of light occurs when a light ray is incident on the interface between two transparent media —

The phenomenon of changing the direction of a light ray upon oblique incidence at the interface of two media is called —

In Figure 5.04, the upper medium is air and the lower medium is —

In the refraction figure, AO represents the —

The line NN' drawn through the point O on the surface of water is called —

Water is optically denser than —

When light travels from air to water, the refracted ray bends —

In Figure 5.04, $\angle AON$ represents the —

In Figure 5.04, $\angle CON'$ represents the —

If a light ray is incident along NO (i.e. along the normal), it will —

In the cup-and-coin experiment, after pouring water the hidden coin becomes visible because —

According to the first law of refraction, the incident ray, the refracted ray and the normal at the point of incidence —

According to the second law of refraction, for a definite pair of media and a particular colour of light —

The constant $n$ in the second law of refraction is called the —

If the first medium is taken as vacuum, the refractive index of the second medium is called its —

The refractive index of water is —

The refractive index of air is essentially taken as —

The refractive index of a medium slightly varies depending on —

A transparent refracting medium bounded by two spherical surfaces is known as —

Most lenses are made of —

Nowadays lenses are also made of —

Lenses are mainly of how many types?

The two main types of lenses are —

The middle part of a convex lens is —

A convex lens is sometimes called a —

A convex lens converges a parallel beam of light to a —

The point at which parallel rays converge after passing through a convex lens is called the —

The distance from the centre of the lens to the focal point along the axis is called —

The middle part of a concave lens is —

A parallel beam of light incident on a concave lens —

The focal point of a concave lens is found by —

The imaginary straight line going through both centres of curvature of a lens is called the —

The power of a lens is defined as the —

The unit of power of a lens is —

If the focal length of a convex lens is 2 meters, its power is —

The power of a convex lens is —

The power of a lens being $+1\,\text{D}$ means it is a convex lens that converges a parallel beam at a distance of —

If the power of a lens is $-2\,\text{D}$, the lens is —

Which of the following is NOT a component of the eye?

The eye acts as which type of lens?

The image formed by a convex (converging) lens of the eye on the retina is —

The image of an object is formed on which part of the eye?

Which cells in the retina convert incident light into electrical signals?

Electrical signals from the retina are transmitted to the brain through —

Cone cells in the retina —

Rod cells in the retina are sensitive to —

Why can we see in faint moonlight but cannot distinguish colours?

The inverted image formed on the retina is turned upright by —

Consider the following statements about the eye:

The minimum distance from the eye up to which an object can be seen distinctly is called the —

The point corresponding to the least distance of distinct vision is called the —

The least distance of distinct vision for a child is approximately —

The least distance of distinct vision for an adult person can be up to —

The far point of a normal eye exists at —

A normal healthy eye can distinctly see any object between —

When the range of normal vision of the eye is disrupted, the condition is called —

The two main defects of the eye discussed in the chapter are —

Shortsightedness is also known as —

A person who can see nearby objects but cannot see distant objects suffers from —

In myopia, the far point of the eye is at —

Which of the following can cause myopia?

In myopia, the image of a distant object is formed —

Myopia is rectified by using spectacles with —

The focal length of the corrective concave lens for myopia is equal to —

Farsightedness is also known as —

A person who can see distant objects clearly but cannot see nearby objects clearly suffers from —

Hypermetropia is normally suffered by —

Which of the following can cause hypermetropia?

In hypermetropia, light rays coming from a nearby point converge —

Hypermetropia is rectified by using spectacles with —

Which vitamins are particularly important for healthy eyes?

Which of the following foods is recommended for good eye health?

How many hours of sleep are recommended at night to keep the eyes energetic?

Which of the following habits is harmful to the eyes?

While outdoors in intensified sunlight, one should use sunglasses that prevent —

While working with chemicals, one should wear —

According to the 20-20 rule recommended in the chapter, while using a monitor one should —

Consider the following statements about eye care:

What is the least distance of distinct vision of a normal eye?

For a convex lens —

What is the name of the defect of the eye mentioned in the figure (image formed in front of the retina)?

What is the cause of this defect (myopia)?

What is refraction of light?

If the least distance of distinct vision for a person is 20 cm, it means —

Sejuti cannot clearly see the writing on the board from the back bench. Which defect is she suffering from?

Sejuti's father cannot read the newspaper held close but can read it after moving it further. He should use spectacles with —

Which type of defect does Sejuti's father suffer from?

The mirror placed on a stand at a blind turn of a hilly road is —

The three mirrors P, Q and R fitted in a car typically consist of —

A lens having a power of $-2\,\text{D}$ means —

Due to which property of light do fish in water appear to be at a higher position than their actual position?

If the focal length of a lens is 2 m, then its power is —

While working on a computer, after how much time should one take a break by looking away?

When light passes obliquely from air through a transparent medium denser than air —

The refractive index of water being 1.33 means —