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3 years ago

What is the photoelectric effect?

Physics

2 answers:

Veronika [31]3 years ago

5 0

Answer:

emissions of electrons from a metal

Explanation:

I did grad point

n200080 [17]3 years ago

4 0

the emission of electrons or other free carriers when light shines on a material.

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Use newton's law to explain the vertical acceleration of a projectile

NISA [10]

Answer:

Explained below

Explanation:

Newton's first law of motion: This law states that an object will remain at rest or continue in constant motion except it's acted upon by an external force. In projectile motion, the horizontal component of velocity will remain unchanged because we ignore air resistance since no force is acting in that horizontal direction.

Newton's second law of motion: This law states that force is the product of mass and acceleration. In projectile the force acts downwards, thus f = mg.

But g = a since internal forces will cancel out.

Thus, F = ma

5 0

3 years ago

A container in the shape of a cube 10.0 cm on each edge contains air (with equivalent molar mass 28.9 g/mol) at atmospheric pres

Vikentia [17]

Answer:

a) m = 1.174 grams

b) F_g = 0.01151 N

c) F_c = 1013 N

Explanation:

Given:

- The length of a cube L = 10.0 cm

- The molar mass of air M = 28.9 g/mol

- Pressure of air P = 101.3 KPa

- Temperature of air T = 300 K

- Universal Gas constant R = 8.314 J/kgK

Find:

(a) the mass of the gas

(b) the gravitational force exerted on it

(d) Why does such a small sample exert such a great force? (6%)

Solution:

- Compute the volume of the cube:

V = L^3 = 0.1^3 = 0.001 m^3

- Use Ideal gas law equation and compute number of moles of air n:

P*V = n*R*T

n = P*V / R*T

n = 101.3*10^3 * 0.001 / 8.314*300

n = 0.04061 moles

- Compute the mass of the gas:

m = n*M

m = 0.04061*28.9

m = 1.174 grams

- The gravitational force exerted on the mass of gas is due to its weight:

F_g = m*g

F_g = 1.174*9.81*10^-3

F_g = 0.01151 N

- The force exerted on each face of cube is due its surface area:

F_c = P*A

F_c = (101.3*10^3)*(0.1)^2

F_c = 1013 N

- The molecules of a gas have high kinetic energy; hence, high momentum. When they collide with the walls they transfer momentum per unit time as force. Higher the velocity of the particles higher the momentum higher the force exerted.

4 0

3 years ago

Which of the

kompoz [17]

C. Amount of oxygen

The others either change but don’t decrease or they increase.

8 0

2 years ago

almost 500 grams of sugar can dissolve in 100 milliters of boiling water. you have a boiling solution of liquid with as much sug

amid [387]

The solution is 'supersaturated' ... holding more solute than it's supposed to be able to hold.

8 0

3 years ago

When talking about the speeds of atoms in a gas you must refer to the average speed because

cluponka [151]

Answer:

An Atom's individual speed will change as it collides with other atoms, so we have to use an average.

Explanation:

In a gas a single atoms does an assortment of things during its time in the gas—sometimes it collides with an other atom gaining a lot of speed, sometimes losing a lot of speed in the collision, and sometimes just moving freely. Therefore: the motion of one individual atom is unpredictable, and it cannot be representative of all the the atoms in a gas, which is why we must average over all speeds of all atoms to find an average speed that allows us to calculate other quantities like temperature and pressure of the gas.

Hence, the second option <em>"an Atom's individual speed will change as it collides with other atoms, so we have to use an average" </em>stands correct.

3 0

3 years ago