Light intensity is the "amount of light given off a light source." Also, is the measure the wavelength of the amount of light given off by a light source.
Hope this helps.
Answer:
The lenses with different focal length are four.
Explanation:
Given that,
Radius of curvature R₁= 4
Radius of curvature R₂ = 8
We know ,
Refractive index of glass = 1.6
When, R₁= 4, R₂ = 8
We need to calculate the focal length of the lens
Using formula of focal length

Put the value into the formula



When , R₁= -4, R₂ = 8
Put the value into the formula



When , R₁= 4, R₂ = -8
Put the value into the formula



When , R₁= -4, R₂ = -8
Put the value into the formula



Hence, The lenses with different focal length are four.
<span>D. sill
A sill forms when hot magma squeezes between layers of rock to form a hardened sheet of rock. A sill is basically a tabular sheet intrusion between old layers of sedimentary rock, volcanic beds, or in the direction of foliation inherent in metamorphic rock. The word sill means a concordant intrusive sheet.</span>
They look green because of the “special pair” of chlorophyll molecules.