To solve this problem we will apply the concepts related to the electric field, linear charge density and electrostatic force.
The electric field is
Here,
= Linear charge density
= Permittivity of free space
r = Distance
The linear charge density can be written as,
Linear charge density is given as
Replacing,
The initial and final electric Force can be written as function of the charge and the electric field as
If we replace the value for the electric field we have,
Length is one third at the end, then
The ratio of the force is
Therefore the required ratio is 3
Answer:
Explanation:
In a LC circuit The time constant τ is the time necessary for 60% of the total current (maximum current), pass through the inductor after a direct voltage source has been connected to it. The time constant can be calculated as follows:
Therefore, the time needed for the current to reach a fraction f = 0.6(60%) of its maximum value is:
I do not know what the school expects as an answer, but advantage of reflecting telescopes is that there is only one major reflecting surface, so it is quite easy to create a 6 or 8 inch telescope by an amateur, after adding on a prism and an eyepiece. (a microscope eyepiece could be used).
MY answer would be "easier to build". (it still takes tens of hours to grind and polish the single plane surface to a parabolic surface).
Electromagnetic waves all have the same velocity in the same medium. However, since frequencies vary widely, so do wavelengths.
Answer:
68.445 cm³/s
Explanation:
Given:
Volume, V = 
radius = 5.85 cm
Growth rate of radius = 0.5 cm/week
now
differentiating the volume with respect to time 't', we get:
or
now, substituting the value of r (i.e at r = 5.85cm) in the above equation, we get:
or
hence, the rate of change of volume at r = 5.85cm is 68.445 cm³/s
