Other Eyes Defects

Q.

The far point of a myopic person is 80cm . What is the power of the lens required to enable him to see very distant objects clearly?

Q. A lens has a power of $10\text{D}$ when placed in air. When it is immersed in water$(\mu =\frac{4}{3})$, the change in power is
(Refractive index of lens material is $1.5$)

1. $2.55\text{D}$
2. $5.0\text{D}$
3. $6.5\text{D}$
4. $-7.5\text{D}$

Q. 41.In a fresnel biprism experiment, the two positions of lens give seperation between the slits as 16 cm and 9 cm respectively. What is the actual distance of seperation? 13 cm 14 cm 12.5 cm 12 cm

Q. The near point and far point of a person are $40\text{cm}$ and $200\text{cm}$ respectively. Find the power of the lens, he/she should use while reading a book kept at distance $25\text{cm}$.

1. $1.5\text{D}$
2. $-1.5\text{D}$
3. $3.5\text{D}$
4. $-3.5\text{D}$

Q. A person's near point is 50 cm and his far point is 3 m. Power of the lenses he requires for (i) reading and
(ii) for seeing distant stars are

1. – 2 D and 0.33 D
2. 2 D and – 0.33 D
3. 2 D and – 3 D
4. – 2 D and 3 D

Q.

A man can see only between 75 cm and 200 cm. The power of lens to correct

the near point will be

1. + 8/3 D
2. + 3 D

3. - 3 D

4. - 8/3 D

Q. A converging lens forms a five fold magnified image of an object. The screen is moved towards the object by a distance $d=0.5\text{m}$ and the lens is shifted so that the image has the same size as the object. Find the power of lens and the initial distance between the object and the screen respectively.

1. $6.4\text{D},11.25\text{m}$
2. $3.2\text{D},9.25\text{m}$
3. $6.4\text{D},22.5\text{m}$
4. None of the above

Q.

Astigmatism (for a human eye) can be removed by using

[CPMT 1972; MP PET/PMT 1988; CBSE PMT 1990]

1. Concave lens

2. Convex lens

3. Cylindrical lens

4. Prismatic lens

Q. The near point and far point of a person are $40\text{cm}$ and $200\text{cm}$ respectively. Find the power of the lens he/she should use while reading at $25\text{cm}$

1. $1.5D$
2. $-1.5D$
3. $3.5D$
4. $-3.5D$

Q.

A myopic person can see things clearly if they lie between 8 cm and 100 cm from his eye. The lens will enable him to see the moon distinctly if its focal length is:

1. zero

2. infinity

3. + 100 cm

4. - 100 cm

Q. 3.The figure shows a silvered lens .Ua=1.6 and Ub= 1.2, R1=80cm , R2=40cm and R3=20cm. An object is placed at a distance of 12cm from this lens.find the image distance.

Q. A person can see clearly objects only when they lie between $50\text{cm}$ and $250\text{cm}$ respectively. The person uses a lens of power $2\text{D}$ , while reading at $25\text{cm}$. With this lens, find the maximum distance clearly visible for the person?

1. $30\text{cm}$
2. $25\text{cm}$
3. $42\text{cm}$
4. $35\text{cm}$

Q. A person looking at a person wearing a shirt with a patterncomprising vertical and horizontal lines is able to see the verticallines more distinctly than the horizontal ones. What is this defect due to? How is such a defect of vision corrected?

Q. The focal length of a concave lens is 2 m, calculate the power of the lens.

1. $-0.5D$
2. $-1.0D$
3. $+0.5D$
4. $+1.0D$

Q. ntIn a fresnel biprism experiment, the two positions of lens give seperation between the slits as 16 cm and 9 cm respectively. What is the actual distance of seperation?n nt13 cmn nt14 cmn nt12.5 cmn nt12 cmn

Q. A person has near point at $100\text{cm}$. What power of lens is needed to read at $20\text{cm}$ if the person uses spectacle, having glasses $2\text{cm}$ away from the eye?

1. $4.54\text{D}$
2. $3.54\text{D}$
3. $5.00\text{D}$
4. $5.54\text{D}$

Q. Is a virtual image always inverted?

Q. Astigmatism (for a human eye) can be removed by using -

1. Concave lens
2. Convex lens
3. Cylindrical lens
4. Prismatic lens

Q.

If there had been one eye of the man, then

1. Image of the object would have been inverted

2. Visible region would have decreased

3. Image would have not been seen three dimensional

4. (b) and (c) both

Q.

If there had been one eye of the man, then

1. Image of the object would have been inverted

2. Visible region would have decreased

3. Image would have not been seen three dimensional

4. (b) and (c) both

Q.

A man can see only between 75 cm and 200 cm. The power of lens to correct

the near point will be

1. + 8/3 D
2. + 3 D

3. - 3 D

4. - 8/3 D

Q.

A man can see only between 75 cm and 200 cm. The power of lens to correct

the near point will be

1. + 8/3 D
2. + 3 D

3. - 3 D

4. - 8/3 D

Q.

A telescope has been adjusted for the relaxed eye. How will you change the distance between the lenses if you need to adjust it for LDDV adjustment?

Q.

for combination of thin lens in contact , for first lens 1/v-1/u=1/f which is lens formula but as u is negtive then why dont we use postive sign i.e. 1/v+1/u=1/f?

Q. For a normal eye, the cornea of the eye provides a converging power of $40\text{D}$, and the least converging power of the eye lens behind the cornea is $20\text{D}$. Using this information, the distance between the retina and the cornea-eye lens can be estimated to be -

1. $1.5\text{cm}$
2. $5\text{cm}$
3. $2.5\text{cm}$
4. $1.67\text{cm}$