Science M.C.Q-[Phy-1M]

3. Cilliary muscles.

3. 25 cm.

4. Retina

2. accommodation.

2. Q.

​​​​​​​Explanation:

Student Q has traced the path correctly.

When light is travelling from a rarer medium to a denser medium, it bends towards the normal to the surface, while the light from a denser medium to a rarer medium bends away from the normal to the surface.

Hence, the correct option is B.

4. Y, Q and P.

​​​​​​​​​​​​​​​​​​​​​Explanation:

The angle made by the incident ray with the normal to the first face of the prism is called incident angle, which is angle Y here.

The angle made by the emergent ray with the normal to the surface when it comes out from the prism after refraction is called emergent angle, which is angle Q here.

The angle between the incident ray and the emergent ray is called angle of deviation, which is angle P here.

Hence, the correct option is D.

4. X, M, Z.

2. The device X is a concave mirror of focal length 30 cm.

3. O, X, M and Z.

​​​​​​​​​​​​​​​​​​​​​​​​​​​​Explanation:

O is the angle of prism.

Angle of incidence is the angle made by the incident ray with the normal to the surface of the prism. Here, X represents the angle of incidence.

Angle of emergence is the angle made by the emerging ray with the normal to the surface of the prism. Here, M represents the angle of emergence.

Angle of deviation is the angle made by the emerging ray with the incident ray. Here, Z represents the angle of deviation.

Hence, the correct option is C.

1. Towards the normal while entering into the prism and away from the normal while emerging out of the prism.

_{​​​​​​​}​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Explanation:

When a ray of light enters a glass prism, it travels from a rarer medium to a denser medium. So, the ray of light bends towards the normal.

When the ray of light emerges from the glass prism, it travels from a denser medium to a rarer medium. So, the ray of light bends away from the normal.

Hence, the correct option is A.

3. III.

Explanation:

When light goes from rarer medium to denser medium it bends towards the normal. The light bends away from the normal when it goes from a denser medium to rarer medium.

This condition is fulfilled in figure (III).

3. I, II and III.

2. (A) and (B).

Explanation:

Virtual Images are images which can only be seen in a mirror but cannot be obtained on the screen. They are formed when light rays after getting reflected from a mirror appear to meet at a point. A virtual image is erect with respect to the object.

3. (A) and (B).

Explanation:

Real Images are images which can be obtained on the screen. They are formed when light rays after getting reflected from a mirror actually meet at a point. A real image is inverted with respect to the object.

3. 180^o

Explanation:

A person's field of view with both eyes open is about 180^o.

3. Both 'A' and 'B' are correct

Explanation:

The young human eye can change focus from distance (infinity) to as near as 6.5cm from the eye. This dramatic change in focal power of the eye of approximately 15

dioptres (the reciprocal of focal length in metres) occurs as a consequence of areduction in zonular tension induced by ciliary muscle contraction.

3. All the colours of the white light move with the same speed.

Explanation:

Speed of light is a constant value regardless of its color.

3. A person with myopia can see nearby objects clearly.

Explanation:

Hypermetropia: A person suffering from this defect can see far off objects clearly but cannot see nearby objects clearly.

Myopia: A person suffering from th is defect can see nearby objects clearly but cannot see far off objects clearly.

4. All of the above

Explanation:

Vitreous humour is a clear gelatinous gel like fluid that fills the space between the lens and the retina.

It helps in maintaining the shape of the retina by holding the retina in its place.

The crystalline lens helps in finer adjustments of focal length required to focus objects at different distances and forms an inverted real image of the object on the retina.

Aqueous humour is present between the lens and the cornea and helps in maintaining the pressure in the eye.

2. Scattering of light

3. Refraction, dispersion and internal reflection.

Explanation: Dispersion results in white light getting segregated into its component colours. Refraction bends the incident light to an angle that is causes internal reflection; and finally rainbow is formed.

3. Twinkling of stars.

Explanation:

Atmospheric refraction is the phenomenon of bending of light on passing through the earth's atmosphere. Twinkling of stars Stars twinkle on account of atmospheric refraction. Starlight undergoes refraction many times before reaching the earth.

2. Scattering of light.

Explanation: Red colour scatters the least and hence travels the farthest. During sunset or sunrise, light has to travel a longer distance to reach us. Hence, only red light reaches to us and the sky appears reddish.

4. Sun appearing red at sunset.

Explantion:

The sun appears red at sunset not because of the atmospheric refraction of light but because of the scattering effect of light.

4. Rainbow

3. Iris.

Explanation:

The iris controls the amount of light entering the eye.

2. Yellow.

Explanation:

Yellow is the colour of white light that is the least deviated by a prism because it has the largest wavelength of the colours given in the alternatives.

3. Violet.

Explanation:

Violet is the colour of white light that has the least wavelength.

1. Violet

Explanation:

The colour violet travels the slowest in a glass prism owing to its short wavelength.

1. The pupil becomes larger.

Explanation:

The pupil becomes larger when you walk out of bright sunshine into a poorly lit room, to allow more light to enter the eye.

2. Iris

1. Hind legs of pig, duck and kangaroo

Explanation:

Homologous structures means that they had come from a common ancestor, e.g., hind legs of pig, duck and kangaroo.

2. Infrared.

Explanation:

Infrared radiation has the maximum wavelength and minimum frequency. Energy is directly proportional to frequency; hence energy associated with them is also low. Thus the infrared radiation gets least scattered by the tiny particles in the fog.

That is why infrared wave is preferred over all others which have a higher frequency and gets scattered hence can’t be focused.

1. Different refractive index for different wavelength of each colour

1. Shortsightedness

Explanation:

When the power of eye lens increases, the object kept at the far point can not be seen clearly because the focal distance of eye lens decreases.

2. Outer surface of cornea

2. Contract

4. The image distance from the eye lens

Explanation:

In the eye, image is always formed at retina which is at a fixed distance in eye.

So, when objects at different distances are seen by the eye, the image distance from the eye lens remains constant by changing radii of curative of the eye lens leading to change in focal length.

2. Outer surface of the cornea

Explanation:

Cornea is the transparent spherical part of the eye covering the iris and pupil.

When an object appears in front of the eye, the rays from the object enter through this transparent cornea and refraction occurs at the outer

2. Outer surface of the cornea.

Explanation:

Most refraction in the eye occurs when light rays travel through the curved, clear front surface of the eye (cornea). The eye's natural lens also bends light rays.

2. Only nearby objects

3. Real and inverted

1. Light dispersion and formation of a 7 colors spectrum.

Explanation:

Upon passage through the prism, the white light is separated into its component colors - red, orange, yellow, green, blue, indigo and violet.

2. Reddish and orange

Explanation:

During sunrise and sunset the sun rays have to pass through a larger distance and also a greater thickness of air since it is low in the sky.

At these positions, the sky looks orange-red colour because photons of red and orange light are least scattered through the atmosphere and are able to reach our eyes.

1. Accommodation of eye

3. Scattering of light.

Explanation:

The Tyndall effect is the scattering of light as a light beam passes through a colloid. The individual suspension particles scatter and reflect light, making the beam visible.

2. Refraction of light by different layers of varying refractive indices.

Explanation: The twinkling of a star is due to atmospheric refraction of light of stars.

2. Cornea

Explanation:

Light enters the eye through a curved front surface known as cornea. It is transparent in nature.

4. The thickness of the eye lens is increased.

Explanation:

The thickness of the eye lens is increased to focus the image of a nearby object on the retina of the eye.

1. Long sight.

Explanation:

As the woman can see distant objects clearly, but not nearby objects, she is suffering from the defect of vision called long sight.