All categories

3 years ago

.How many electrons are in 0.4 C?

Physics

1 answer:

konstantin123 [22]3 years ago

4 0

Answer:

There are 2.5 x 10¹⁸ electrons in 0.4 C.

Explanation:

The charge of one electron = 1.602 x 10⁻¹⁹ C

Therefore, the number of electrons in 0.4 C is calculated as follows;

1.602 x 10⁻¹⁹ C -------------> 1 electron

0.4 C --------------------------> x

x = (0.4 ) / (1.602 x 10⁻¹⁹)

x = 2.5 x 10¹⁸ electrons

Therefore, there are 2.5 x 10¹⁸ electrons in 0.4 C.

You might be interested in

A mechanic pushes a 2.60 ✕ 103-kg car from rest to a speed of v, doing 5,430 J of work in the process. During this time, the car

Oduvanchick [21]

Part A. We are given that a car is pushed from rest to a final speed doing 5430 Joules of work. -

To determine the final velocity we will use the work and energy theorem which states that the work done is equal to the change in kinetic energy:

$W=K_f-K_0$

Since the car starts from rest this means that the initial kinetic energy is zero:

$W=K_f$

The kinetic energy is given by:

$K=\frac{1}{2}mv^2$

Substituting in the formula we get:

$W=\frac{1}{2}mv_f^2$

Now, we solve for the final velocity. First, we multiply both sides by 2 and divide both sides by the mass:

$\frac{2W}{m}=v_f^2$

Now, we take the square root to both sides:

$\sqrt{\frac{2W}{m}}=v_f$

Now, we plug in the values:

$\sqrt{\frac{2(5430J)}{2.6\times10^3kg}}=v_f$

Solving the operations:

$2.04\frac{m}{s}=v_f$

Therefore, the final velocity is 2.04 m/s.

Part B. Now, we use the following formula for work:

$W=Fd$

Where "F" is the force and "d" is the distance.

Now, we set this equation equal to the work done by the force:

$Fd=5430J$

Now, we divide both sides by the distance "d":

$F=\frac{5430J}{29m}=187.2N$

Therefore, the force exerted is 187.2 Newton.

7 0

2 years ago

A force of 30 N is applied tangentially to the rim of a solid disk of radius 0.14 m. The disk rotates about an axis through its

jenyasd209 [6]

Answer:

3.8 kg

Explanation:

The torque, τ, due to the force, F, is given by

$\tau = F\times r$

where r is the radius.

This torque is also given by

$\tau = I\times\alpha$

where I and α are respectively the moment of inertia and the angular acceleration.

For a solid disk, its moment of inertia for an axis though its centre and perpendicular to its face is given by

$I = \frac{1}{2}mr^2$

where m is its mass and r is its radius.

Hence, we have

$\tau = F\times r = I\times\alpha=\frac{1}{2}mr^2\times\alpha$

$m = \dfrac{2F}{r\alpha} = \dfrac{2(30\ \text{N})}{(0.14\ \text{m})(115\ \text{rad/s}^2)} = 3.8\ \text{kg}$

5 0

3 years ago

Read 2 more answers

A cell phone weighing 80 grams is flying through the air at 15 m/s what is the kinetic energy

hjlf

Answer:

$9\:\mathrm{J}$

Explanation:

Kinetic energy is given by the following equation:

$KE=\frac{1}{2}mv^2$ , where $m$ is mass in $\mathrm{kg}$ and $v$ is velocity in $\mathrm{m/s}$ .

Since the cell phone's mass is given in grams, we need to convert this into kilograms:

$80\:\mathrm{g}\cdot \frac{1\:\mathrm{kg}}{1000\:\mathrm{g}}=0.08\:\mathrm{kg}$ .

Therefore, the kinetic energy of the cell phone is:

$KE=\frac{1}{2}\cdot 0.08\cdot 15^2=\fbox{$9\:\mathrm{J}$}$ .

3 0

3 years ago

Bella makes the 2.5m distance to her food bowl in 9.1 seconds. What is her average velocity?

e-lub [12.9K]

Distance=2.5m
Time=9.1s

Average Velocity=Total Distance/Total Time

$\\ \sf\longmapsto \dfrac{2.5}{9.1}$

$\\ \sf\longmapsto 0.3m/s$

7 0

3 years ago

Which two factors does the power of a machine depend on?

lianna [129]

The power of a machine depend on two factors are work and time.

Option C

Explanation:

In science, power defined as the amount of work done in a unit time. i.e. delivering work in a rate of time or energy supply, expressed in input of work or transmitted energy divided by the time interval (t) or W/t.

Example: Some work can be done in the long run with a low-power engine or in a short time with a motor with high performance. The equation for power can be given as

$Power\ (in\ watts) =\frac{\text { work (joules) }}{\text { time (seconds) }}$

$P=\frac{W}{t}$

7 0

3 years ago