Answer:

Given:

Far point = 80 cm

Spectacle power = -1.0 D

The formula relating lens power (P), focal length (f), and object distance (u) is:

P = 1/f

Since the spectacle power is -1.0 D, we can convert it to focal length using the formula:

f = 1/P

f = 1/-1.0 = -1.0 m^-1 (Note: The negative sign indicates a concave lens used for myopia correction.)

Now, we can use the lens formula to find the object distance (u) when the image distance (v) is at infinity:

1/f = 1/v - 1/u

Since the far point is considered to be at infinity, we can assume v = infinity and simplify the equation:

1/f = 0 - 1/u

1/f = -1/u

Substituting the value of f:

-1.0 m^-1 = -1/u

Simplifying the equation:

u = 1.0 m

Therefore, the myopic person can see clearly up to a distance of 1.0 meter.

Answer:

Here,

P

=

−

0.80

d

i

o

p

t

r

e

f

=

100

P

=

100

−

0.8

=

−

125

c

m

v

=

−

80

c

m

,

u

=

?

As

1

v

−

1

u

=

1

f

∴

1

u

=

1

v

−

1

f

=

1

−

80

+

1

125

=

−

25

+

16

2000

=

−

9

2000

u

=

−

2000

9

=

−

222.22

c

m

The person can see objects upto

222.22

c

m

(b) Here,

P

=

1.0

d

i

o

p

t

r

e

f

=

100

P

=

100

1

=

100

c

m

u

=

?

v

=

−

75

c

m

As

1

−

1

u

=

1

f

∴

1

u

=

1

v

−

1

f

=

−

1

75

−

1

100

=

−

4

−

3

300

u

=

−

300

7

=

−

42.9

c

m

.