Answer:
Explanation:
Let the linear charge density of the charged wire is given as
here we can use Gauss law to find the electric field at a distance r from wire
so here we will assume a Gaussian surface of cylinder shape around the wire
so we have
here we have
so we have
Answer:
The person should use a convex lens of power -0.625 D.
Explanation:
Given that, the far point of the person, with myopic eye, is 160 cm.
It means that the image of an object, which is at infinity, is formed at this point 160 cm distance away from the person's eye.
If the object is infinity, then the object distance, u = -.
Image distance, v = -160 cm.
u and v are taken to be negative because the object and the image of the object are on the side of the eye from where the light is coming.
Let the focal length of the lens which is to be used for the correction of this myopic eye be f, then using lens equation,
The negative focal length indicates that the lens should be convex.
The power of the lens is given by
So, the person should use a convex lens of power -0.625 D.