Respuesta :
Answer: f=150cm in water and f=60cm in air.
Explanation: Focal length is a measurement of how strong light is converged or diverged by a system. To find the variable, it can be used the formula:
[tex]\frac{1}{f}[/tex] = (nglass - ni)([tex]\frac{1}{R1}[/tex] - [tex]\frac{1}{R2}[/tex]).
nglass is the index of refraction of the glass;
ni is the index of refraction of the medium you want, water in this case;
R1 is the curvature through which light enters the lens;
R2 is the curvature of the surface which it exits the lens;
Substituting and calculating for water (nwater = 1.3):
[tex]\frac{1}{f}[/tex] = (1.5 - 1.3)([tex]\frac{1}{10}[/tex] - [tex]\frac{1}{15}[/tex])
[tex]\frac{1}{f}[/tex] = 0.2([tex]\frac{1}{30}[/tex])
f = [tex]\frac{30}{0.2}[/tex] = 150
For air (nair = 1):
[tex]\frac{1}{f}[/tex] = (1.5 - 1)([tex]\frac{1}{10}[/tex] - [tex]\frac{1}{15}[/tex])
f = [tex]\frac{30}{0.5}[/tex] = 60
In water, the focal length of the lens is f = 150cm.
In air, f = 60cm.
Answer:
focal length of the lens when immersed in water is 150cm
focal length of the lens if it is in air is 60cm.
It can be calculated using the equation
1/f = (Refractive index of the glass - Reflective index of the medium)x[ 1/R1 - 1/R2]
Where R1 is the radius of curvature of the surface through which light will enter the lens, and
R2 is the radius of curvature of the surface from which light will exit the lens.
Explanation:
Since n-water = 1.3
focal length of the lens if it is immersed in water is
1/f = (n - 1.3)[1/R2 -1/R1]
1/f = (1.5 - 1.3)[1/10 - 1/15]
1/f = 0.2 x (2/60)
f = 60/0.4 = 150cm
Since n-air = 1
focal length of the lens if it is in air is calculated as:
1/f = (n - 1)[1/R2 -1/R1]
1/f = (1.5 - 1)[1/10 - 1/15]
1/f = 0.5 x (2/60)
f = 60/1= 60cm
Note: The values are measured in centimetre and not converted to metre
