The focal length of a lens needed by a woman whose near point is 50cm from her eyes is 50cm.
To find the answer, we have to know about the focal length of correcting lens.
<h3>
How to find the focal length of
correcting lens?</h3>
- If x is the distance of nearest point of the defective eye and D is the least distance of distinct vision, then, the expression for focal length of the correcting lens will be,

- It is given that, the woman whose near point is 50cm from her eyes, assuming the least distance of distinct vision for a normal eye is 25cm. Thus, the focal length will be,

Thus, we can conclude that, the focal length of a lens needed by a woman whose near point is 50cm from her eyes is 50cm.
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Answer:
Species A and C
Explanation: none
Answer:
1.492*10^14 electrons
Explanation:
Since we know the mass of each balloon and the acceleration, let’s use the following equation to determine the total force of attraction for each balloon.
F = m * a = 0.012 * 1.9 = 0.0228 N
Gravitational forces are negligible
Charge force = 9 * 10^9 * q * q ÷ 225
= 9 * 10^9 * q^2 ÷ 225 = 0.0228
q^2 = 5.13 ÷ 9 * 10^9
q = 2.387 *10^-5
This is approximately 2.387 *10^-5 coulomb of charge. The charge of one electron is 1.6 * 10^-19 C
To determine the number of electrons, divide the charge by this number.
N =2.387 *10^-5 ÷ 1.6 * 10^-19 = 1.492*10^14 electrons
Explanation:
radio waves, which include visible light waves.