Question

‼️Please answer with simple explanation‼️
$\huge\underline\red{Question- 1}$
The focal length of a magnifying glass is 25 cm. What is its magnifying power?
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$\huge\underline\red{Question - 2}$
The magnifying power of a simple microscope is 6. What is the focal length of its lens?
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Final results are given, solve the initial part;
1. 4
2. 16.67cm
$\large \fbox \red{no \: spming}$
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Answer 1

Answer:

1. Given :- m=n/f+1

Given :- m=n/f+1Here n is the near point which =25m

Given :- m=n/f+1Here n is the near point which =25mSo , m= 25/2.5+1

Given :- m=n/f+1Here n is the near point which =25mSo , m= 25/2.5+110+1 =11

So it can magnify an object 11 times.

2. Focal length, usually represented in millimeters (mm), is the basic description of a photographic lens. ... The longer the focal length, the narrower the angle of view and the higher the magnification. The shorter the focal length, the wider the angle of view and the lower the magnification.

Answer 2

Important :-

• m = $\dfrac{D}{f}$ + 1

• Least Distance of Distinct Vision, D = 25 cm

a. Focal length, f = 25 cm

Magnifying power = $\sf P_{m}$

• m = $\dfrac{25}{25}$ + 1

• m = 2

b. Magnifying power of a simple microscope, $\sf P_{m}$ = 6

Focal length = f

• 6 = $\dfrac{25}{f}$ + 1

• 6 = $\dfrac{25 + f}{f}$

• 6f = 25 + f

• 6f - f = 25

• 5f = 25

• f = $\dfrac{25}{5}$

• f = 5 cm

Hope it helps!