What is the formula for lead (2) bromide

What happens as a result of photoelectric effect

natka813 [3]

Electrons are emitted from the surface of a metal in photoelectric effect.

<h3>What is the photoelectric effect?</h3>

The photoelectric effect is the emission of electron from the surface of a metal when light is shone on the surface..

For electrons to be emitted, the light must have a certain frequency known as threshhold frequency.

Therefore, electrons are emitted from the surface of a metal in photoelectric effect.

Learn more about photoelectric effect at: brainly.com/question/21320305

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5 0

2 years ago

At room temperature (20°C} and pressure, the density of air is 1.189 g/L. An object will float in air if its density is less tha

Alekssandra [29.7K]

Explanation:

$Density =\frac{Mass}[Volume}$

Density of the air ,d= 1.189 g/L

(a) Density of the evacuated ball

Mass of the ball ,m = 0.12 g

Volume of the ball = $V=560 cm^3=560 ml=0.560 L$

$D =\frac{0.12 g}{0.560 L}=0.214 g/L$

D<d, teh evacuated ball will flaot in air.

(b) Density of the evacuated ball D = 0.214 g/L

Density of carbon dioxide gas = $d_1=1.830 g/L$

Mass of the carbon dioxide gas :

$1.830 g/L\times 0.560 L=1.0248 g$

Total density of filled ball with carbon dioxide gas:

$\frac{0.12 g+1.0248 g}{0.560 L}==2.044 g/L$

The ball filled with carbon dioxide will not float in the air because total density of filled ball is greater than the density of an air.

(c) Density of the evacuated ball D = 0.214 g/L

Density of hydrogen gas = $d_2=0.0899 g/L$

Mass of the hydrogen gas :

$1.830 g/L\times 0.560 L=0.050344 g$

Total density of filled ball with hydrogen gas:

$\frac{0.12 g+0.050344 g}{0.560 L}==0.3041 g/L$

The ball filled with hydrogen will float in the air because total density of filled ball is lessor than the density of an air.

(d) Density of the evacuated ball D = 0.214 g/L

Density of oxygen gas = $d_3=1.330 g/L$

Mass of the oxygen gas :

$1.330 g/L\times 0.560 L=1.7448 g$

Total density of filled ball with oxygen gas:

$\frac{0.12 g+1.7448 g}{0.560 L}=1.5442 g/L$

The ball filled with oxygen will not float in the air because total density of filled ball is greater than the density of an air.

(e) Density of the evacuated ball D = 0.214 g/L

Density of nitrogen gas = $d_4=1.165 g/L$

Mass of the nitrogen gas :

$1.165 g/L\times 0.560 L=0.6524 g$

Total density of filled ball with nitrogen gas:

$\frac{0.12 g+0.6524 g}{0.560 L}==1.3792 g/L$

The ball filled with nitrogen will not float in the air because total density of filled ball is greater than the density of an air.

f) Mass must be added to sink the ball = m

Density of ball > Density of the air ; to sink the ball.

$\frac{0.12g +m}{0.560L}>1.189 g/L$

m > 0.54584 g

For any case weight added to ball to make it sink in an air should be grater than the value of 0.54584 grams.

5 0

3 years ago

A little boy places an ice cube in his hot bowl of stew and then walks out of the room. When he returns, the ice cube is gone.

Alenkinab [10]

Answer:

b

Explanation:

the ice melted

3 0

3 years ago

Which of these describes an ethical dilemma that drug designers could face?

LenKa [72]

The statement 'whether people should take medicine or if they should seek alternative treatments' describes an ethical dilemma that drug designers face.

<h3>What is drug development?</h3>

Drug development refers to all the processes from target drug identification to drug validation and commercialization.

Drug development involves different stages of development including preclinical and clinical trials.

Ethical dilemmas in drug development include the release of a drug that is ineffective when compared to parallel treatments.

Learn more about drug development here:

brainly.com/question/8187660

4 0

2 years ago

Which of the following uses light energy to convert co2 and h2o to organic compounds?

Dimas [21]

Photosynthesis is where carbon dioxide and water through light energy is converted in glucose and other organic compounds.

4 0

3 years ago