When a light wave enters into a medium of different optical density,

A negatively charged balloon has 4 μC of charge. How many excess electrons are on this bal- loon? The elemental charge is 1.6 ×

bagirrra123 [75]

Data:

The charge of a body depends on the amount of electrons it gains or loses. Q = n * e, where "Q" is charge, "n" is the number of plus or minus electrons, and "e" is the fundamental charge of an electron $1,6 * 10 ^{-19}C$ <span>. To know if the body has gained or lost, we look at the signal of its charge, remembering that the electron is negative. The charge of the body is 4 μC (positive), so there is a lack of electrons!

Q = 4 </span>μC → $Q = 4*10^{-6}$
$e = 1,6 * 10 ^{-19}C$
$n = ?$ <span>

We have:
</span> $Q = n*e$
$n = \frac{Q}{e}$
$n = \frac{4*10^{-6}}{1,6 * 10 ^{-19}}$
$n = 2,5*10^{-6-(-19)}$
$n = 2,5*10^{-6+19}$
$\boxed{n = 2,5*10^{13}electrons}$

7 0

3 years ago

A hollow cylinder of mass 2.00 kgkg, inner radius 0.100 mm, and outer radius 0.200 mm is free to rotate without friction around

kipiarov [429]

Answer: 2.86 m

Explanation:

To solve this question, we will use the law of conservation of kinetic and potential energy, which is given by the equation,

ΔPE(i) + ΔKE(i) = ΔPE(f) + ΔKE(f)

In this question, it is safe to say there is no kinetic energy in the initial state, and neither is there potential energy in the end, so we have

mgh + 0 = 0 + KE(f)

To calculate the final kinetic energy, we must consider the energy contributed by the Inertia, so that we then have

mgh = 1/2mv² + 1/2Iw²