## Question 1: The change in focal length of an eye lens to focus the image of objects at varying distances is done by the action of ________.

1. | pupil |

2. | ciliary muscles |

3. | retina |

4. | blind spot |

## Question 2: Far point of a normal eye is situated at _________.

1. | 25 cm |

2. | infinity |

3. | 50 cm |

4. | 400 cm |

**Question3:**Power of a lens is expressed in

1. | dioptre |

2. | cm |

3. | metre |

4. | millimetre |

## Question 4: 1 D is the power of a lens of focal length ______ cm.

1. | 100 |

2. | 10 |

3. | 1/100 |

4. | 1/10 |

## Question 5: Hypermetropia is rectified by using

1. | convex lens |

2. | concave lens |

3. | cylindrical lens |

4. | progressive lens |

## Question 6: Reciprocal of focal length in metres is known as the ______ of a lens.

1. | focus |

2. | power |

3. | power of accommodation |

4. | far point |

**Question7:**The power of a convex lens of focal length 50 cm is ______.

1. | + 2 D |

2. | - 2 D |

3. | 50 D |

4. | - 5 D |

**Question8:**Two lenses having powers +2D and -4D respectively are put together. Power of the combination would be

1. | -2 D |

2. | +2 D |

3. | -4 D |

4. | +4 D |

**Question9:**The fluid between the retina and the lens is called _______.

1. | aqueous humour |

2. | vitreous humour |

3. | aqua |

4. | humus |

**Question10:**Two thin lenses of power +5D and -2D are put in contact with each other. Focal length of the combination is

1. | +3 m |

2. | -3 m |

3. | 0.33 m |

4. | -0.33 m |

**Question11:**The focal length of a lens whose power is -1.5 D is _______.

1. | -66.66 cm |

2. | + 1.5 m |

3. | + 66.66 cm |

4. | -1.5 m |

**Question12:**The lens formula in cartesian frame is ______________.

1. | |

2. | |

3. | |

4. | |

**Question13:**The part of the lens through which the ray of light passes without suffering deviation is called ________.

1. | optical centre |

2. | focus |

3. | centre of curvature |

4. | pole |

**Question14:**Convex lens always gives a real image if the object is situated beyond _______.

1. | optical centre |

2. | centre of curvature |

3. | focus |

4. | radius of curvature |

**Question15:**Parallel rays of light entering a convex lens always converge at _______.

1. | centre of curvature |

2. | the principal focus |

3. | optical centre |

4. | the focal plane |

**Question16:**Where should an object be placed so that a real and inverted image of the same size is obtained, using a convex lens?

1. | Between O and F |

2. | At F |

3. | At 2 F |

4. | At infinity |

**Question17:**SI unit of the power of a lens is ___________.

1. | dioptre |

2. | cm |

3. | metre |

4. | watt |

**Question18:**In a simple microscope lens used is __________.

1. | biconvex |

2. | biconcave |

3. | plano convex |

4. | cylindrical |

**Question19:**A convex lens is called _________.

1. | converging lens |

2. | diverging lens |

3. | both converging and diverging lens |

4. | refracting lens |

**Question20:**A positive magnification greater than unity indicates _____________________.

1. | real image |

2. | virtual image |

3. | neither real not virtual image |

4. | distorted image |

**Question21:**The power of a convex lens of focal length 50 cm is ______.

1. | + 2D |

2. | - 2D |

3. | 50 D |

4. | - 5D |

**Question22:**Real images formed by single convex lenses are always ________________.

1. | on the same side of the lens as the object |

2. | inverted |

3. | erect |

4. | smaller than the object |

**Question23:**An object is placed 12 cm from a convex lens whose focal length is 10 cm. The image must be.

1. | virtual and enlarged |

2. | virtual and reduced in size |

3. | real and reduced in size |

4. | real and enlarged |

**Question24:**The image produced by a concave lens is ________.

1. | always virtual and enlarged |

2. | always virtual and reduced in size |

3. | always real |

4. | sometimes real, sometimes virtual |

**Question25:**A virtual image is formed by _______.

1. | a slide projector in a cinema hall |

2. | the ordinary camera |

3. | a simple microscope |

4. | telescope |

**Question26:**An object is placed 25 cm from a convex lens whose focal length is 10 cm. The image distance is ________ cm.

1. | 50 cm |

2. | 16.66 cm |

3. | 6.66 cm |

4. | 10 cm |

**Question27:**The least distance of distinct vision is ______.

1. | 25 cm |

2. | 25 m |

3. | 0.25 cm |

4. | 2.5 m |

**Question28:**A convex lens has a focal length of 20 cm. Its power in dioptres is ___________.

1. | 2 |

2. | 5 |

3. | 0.5 |

4. | 0.2 |

**Question29:**The phenomenon by which the incident light falling on a surface is sent back into the same medium is known as ________.

1. | polarization |

2. | reflection |

3. | refraction |

4. | absorption |

**Question30:**The image formed by a plane mirror is always _______.

1. | real and erect |

2. | virtual and erect |

3. | real and inverted |

4. | virtual and inverted |

**Question31:**The centre of the sphere of which the spherical mirror forms a part is called ____________.

1. | centre of curvature |

2. | focus |

3. | pole |

4. | vertex |

**Question32:**The focus of a concave mirror is ________.

1. | real |

2. | virtual |

3. | undefined |

4. | at the pole |

**Question33:**A converging mirror is known as ________.

1. | convex mirror |

2. | plane mirror |

3. | concave mirror |

4. | cylindrical mirror |

**Question34:**The relation between the focal length and radius of curvature of a mirror is _______.

1. | |

2. | R + 2 = f |

3. | f = R/2 |

4. | f = 2 R |

**Question35:**An image formed by a convex mirror is always ________.

1. | virtual, erect and diminished |

2. | virtual, real and magnified |

3. | real, inverted and diminished |

4. | real, erect and magnified |

**Question36:**If the image formed by a concave mirror is virtual, erect and magnified, then the object is placed __________.

1. | between the pole of the mirror and the focus |

2. | beyond the centre of curvature |

3. | at the centre of curvature |

4. | at the focus |

**Question37:**Dentists use a _____________ to focus light on the tooth of a patient.

1. | concave mirror |

2. | convex mirror |

3. | plane mirror |

4. | cylindrical mirror |

**Question38:**What is the value of q in the following diagram?

1. | 30 ^{o} |

2. | 45 ^{o} |

3. | 90 ^{o} |

4. | 60 ^{o} |

**Question39:**What is the angle between the incident and reflected rays when a ray of light is incident normally on a plane mirror?

1. | 90 ^{o} |

2. | 45 ^{o} |

3. | 180 ^{o} |

4. | 0 |

**Question40:**Name the type of image that can be obtained on a screen.

1. | Virtual |

2. | Real |

3. | Diverging |

4. | Converging |

**Question41:**A ray of light is incident on a plane mirror and the angle of incidence is 25

^{o}. What is the angle of reflection?

1. | 0 |

2. | 50 ^{o} |

3. | 90 ^{o} |

4. | 25 ^{o} |

**Question42:**Which of the following is used to make a periscope?

1. | Concave mirror |

2. | Convex mirror |

3. | Plane mirror |

4. | Lens |

**Question43:**Which mirror has a wider field of view?

1. | Convex mirror |

2. | Concave mirror |

3. | Plane mirror |

4. | Cylindrical mirror |

**Question44:**The focal length of a concave mirror is 15 cm. What is its radius of curvature?

1. | 15 cm |

2. | 30 cm |

3. | 7.5 cm |

4. | 45 cm |

**Question45:**The focal length of a mirror is 15 cm. Identify the type of mirror.

1. | Concave mirror |

2. | Plane mirror |

3. | Convex mirror |

4. | Cylindrical mirror |

**Question46:**A ray of light passing through the _______ retraces its path.

1. | focus |

2. | centre of curvature |

3. | pole |

4. | vertex |

**Question47:**When an object is placed at the focus of a concave mirror, the image will be formed at ________.

1. | infinity |

2. | focus |

3. | centre of curvature |

4. | pole |

**Question48:**An object of size 2.0 cm is placed perpendicular to the principal axis of a concave mirror. The distance of the object from the mirror equals to the radius of curvature. The size of the image will be ______________.

1. | 0.5 cm |

2. | 1.5 cm |

3. | 1.0 cm |

4. | 2.0 cm |

**Question49:**If an incident ray passes through the centre of curvature of a spherical mirror, the reflected ray will __________________.

1. | pass through the focus |

2. | pass through the centre of curvature |

3. | pass through the pole |

4. | retrace its path |

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