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3 years ago

If an electron is accelerated from rest through a potential difference of 9.9 kV, what is its resulting speed

Physics

1 answer:

beks73 [17]3 years ago

8 0

Answer:

v = 5.9 x 10⁷ m/s

Explanation:

The kinetic energy of the electron in terms of potential difference is given as:

$K.E = eV$ --------------- equation (1)

where,

e = charge on electron = 1.6 x 10⁻¹⁹ C

V = Potential Difference = 9.9 KV = 9900 Volts

The kinetic energy in general is given as:

$K.E = \frac{1}{2}mv^{2}\\$ --------- equation (2)

where,

m = mass of electron = 9.1 x 10⁻³¹ kg

v = speed of electron = ?

Therefore, comparing equation (1) and equation (2), we get:

$\\\frac{1}{2}mv^{2} = eV\\\\\frac{1}{2}(9.1\ x\ 10^{-31}\ kg)v^{2} = (1.6\ x\ 10^{-19}\ C)(9900\ volts)\\\\v = \sqrt{34.81\ x\ 10^{14}} \\$

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If an electron moves in a circle of radius 21 cm perpendicular to a B field of 0.4 T, what are the speed of the electron and the

kodGreya [7K]

Answer:

$v = 4.048 *10^6$ m/s

Angular frequency = $1.92 * 10^7$

Explanation:

As we know

$v = \frac{qBr}{m}$

q is the charge on the electron = $3.2 * 10^{-19}$ C

B is the magnetic field in Tesla = $0.4$ T

r is the radius of the circle = $0.21$ m

mass of the electrons = $6.64 * 10^{-27}$ Kg

Substituting the given values in above equation, we get -

$v = \frac{3.2 * 10^{-19}*0.4*0.21}{6.64 * 10^{-27}} \\v = 4.048 *10^6$ m/s

Angular frequency =

$\frac{4.048 * 10^6 }{0.21} \\1.92 * 10^7$

8 0

3 years ago

A 55-kg woman is wearing high heels.

Grace [21]

Answer:

Pressure, $P=1.90\times 10^7\ Pa$

Explanation:

It is given that,

Mass of the woman, m = 55 kg

Diameter of the circular cross section, d = 6 mm

Radius, r = 3 mm = 0.003 m

Let P is the pressure exerted on the floor. It is equal to the force acting on woman per unit area. It is given by :

$P=\dfrac{F}{A}$

$P=\dfrac{mg}{\pi r^2}$

$P=\dfrac{55\times 9.8}{\pi (0.003)^2}$

$P=1.90\times 10^7\ Pa$

So, the pressure exerted on the floor is $1.90\times 10^7\ Pa$ . Hence, this is the required solution.

7 0

3 years ago

Why does it matter if a material is amorphous or crystalline? How does the arrangement of atoms affect the properties of materia

Rashid [163]

Answer:

<em>It matters because crystalline and amorphous materials have different properties. The arrange affects the melting point (defined in crystals and a larger range in amorphous) and shape (geometrical in crystals, no geometrical in amorphous). </em>

Explanation:

The particles that compose a solid material are held in place by strong tractive forces between them when we analyze solids we consider the position of the atoms (molecules or ions) rather than their motion (which is important in liquids and gases). This positioning can be arranged in two general ways:

Crystalline solids have internal structures that in turn lead to distinctive flat surfaces or face, these faces intersect at angles that are characteristic of the substance, crystals tend to have sharp, well defined and high melting points because of the same distance from the same number and type of neighbors. They generally have geometric shapes, some examples are diamonds, metals, salts.
Amorphous solids produce irregular or curved surfaces when broken and they have poorly defined patterns when exposed to x rays because of their irregular array. In contrast with crystal solids, amorphous solids soften over a wide temperature range due to the different amounts of thermal energy needed to overcome different interactions. Some examples of these solids are gels, plastics, and some polymers.

I hope you find this information useful and interesting! Good luck!

8 0

3 years ago

The orbital motion of Earth around the Sun leads to an observable parallax effect on the nearest stars. For each star listed, ca

Murrr4er [49]

Answer:

Following are the answer to this question:

Explanation:

Formula:

$D(PC) =\frac{1}{parallax}\\\\D(av)=D(PC) \times 20.626\ J$