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3 years ago

Describe the phenomenon of photoelectric emission

Physics

1 answer:

Solnce55 [7]3 years ago

4 0

Answer:

Photoelectric effect, phenomenon in which electrically charged particles are released from or within a material when it absorbs electromagnetic radiation. The effect is often defined as the ejection of electrons from a metal plate when light falls on it.

Explanation:

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In nature, where do fusion reactions take place?

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Fusion reactions happen in stars

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3 years ago

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What force causes a 1-kg mass to accelerate at a rate of 1 meter per second each second?

Zigmanuir [339]

Answer:

$F=1N$

Explanation:

Conceptual analysis

To solve this problem we apply Newton's second law:

The acceleration of an object is proportional to the force F acting on it and inversely proportional to its mass m.

a = F / m

Where,

F = m * a Formula (1)

F: Force in Newtons (N)

m: mass in kg

a: acceleration in m/(s^2)

a = v / t Formula (2)

v: speed in m/s

t: time in seconds (s)

Known information

We know the following data:

m = 1kg

v = 1 m/s

t = 1s

Development of the problem:

In the Formula (2): $a = \frac{\frac{1m}{s}}{1s} = 1 \frac{m}{s^2}$

In the Formula (1): $F=1kg* 1 \frac{m}{s^2}=1N$

8 0

3 years ago

The heat loss from a boiler is to be held at a maximum of 900Btu/h ft2 of wall area. What thickness of asbestos (k= 0.10 Btu/h f

zmey [24]

Answer:

a. 0.122 ft b. -70 Btu/h ft² c. 633.33 °F

Explanation:

a. Since the rate of heat loss dQ/dt = kAΔT/d where k = thermal conductivity, A = area, ΔT = temperature gradient and d = thickness of insulation.

Now [dQ/dt]/A = kΔT/d

Given that [dQ/dt]/A = rate of heat loss per unit area = -900Btu/h ft², k = 0.10 Btu/h ft ℉(for asbestos), ΔT = T₂ - T₁ = 500 °F - 1600 °F = -1100 °F. We need to find the thickness of asbestos, d. So,

d = kΔT/[dQ/dt]/A

d = 0.10 Btu/h ft ℉ × -1100 °F/-900Btu/h ft²

d = 0.122 ft

b. If the 3 in thick Kaolin is added to the outside of the asbestos, and the outside temperature of the asbestos is 250℉, the heat loss due to the Kaolin is thus

[dQ/dt]/A = k'ΔT'/d'

k' = 0.07 Btu/h ft ℉(for Kaolin), ΔT' = T₂ - T₁ = 250 °F - 500 °F = -250 °F and d' = 3 in = 3/12 ft = 0.25 ft

[dQ/dt]/A = 0.07 Btu/h ft ℉ × -250 °F/0.25 ft

[dQ/dt]/A = -70 Btu/h ft²

c. To find the temperature at the interface, the total heat flux equals the individual heat loss from the asbestos and kaolin. So

[dQ/dt]/A = k(T₂ - T₁)/d + k'(T₃ - T₂)/d' where [dQ/dt]/A = -900Btu/h ft², k = 0.10 Btu/h ft ℉(for asbestos), k' = 0.07 Btu/h ft ℉(for Kaolin), T₁ = 1600 °F, T₂ = unknown and T₃ = 250℉.

Substituting these values into the equation, we have

-900Btu/h ft² = 0.10 Btu/h ft ℉(T₂ - 1600 °F)/0.122 ft + 0.07 Btu/h ft ℉(250℉ - T₂)/0.25 ft

-900Btu/h ft² = 0.82 Btu/h ft ℉(T₂ - 1600 °F) + 0.28Btu/h ft ℉(250℉ - T₂)

-900 °F = 0.82(T₂ - 1600 °F) + 0.28(250℉ - T₂)

-900 °F = 0.82T₂ - 1312°F + 70 °F - 0.28T₂

collecting like terms, we have

-900 °F + 1312°F - 70 °F = 0.82T₂ - 0.28T₂

342 °F = 0.54T₂

Dividing both sides by 0.54, we have

T₂ = 342 °F/0.54

T₂ = 633.33 °F

8 0

3 years ago

A cyclist acceleration from 0m/s to 8m/s in 3second. what is his acceleration?

umka2103 [35]

Answer:

2.66 m/s² .

Explanation:

Initial velocity , u = 0 m/s

Final Velocity , v = 8 m/s

Time Taken , t = 3 s

So , Acceleration = (v-u)/t = (8 m/s - 0 m/s) /3 sec . = 8/3 m/s² = 2.66 m/s²

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3 years ago

Please help me on due today

Bad White [126]

Subject-Matter Achievement Goal

1. My subject-matter achievement goal is:

Answer: Read 1 full chapter book in 1 week

2. My action steps are:

Answer: Read an equal amount of chapters every day for a week

3. My time frame is:

Answer: 1 week

4. Assets and Strengths:

Answer: ability to focus,

5. Motivation:

Answer: Great interest in the book I chose

6. Obstacles:

Answer: Might lose page number, forget where I am at in the book, forget to read one day

7. Solutions:

Answer: Get or make a bookmark, keep a personal reading log, set alarm for a certain time each day

Study/Organizational Skills Goal

8. My study/organizational skills goal is:

Answer: manage my time better

9. My action steps are:

Answer: planning things out to be more organized

10. My time frame is:

Answer: from now to the end of the school year

11. Assets and Strengths:

Answer: a planner so I can pace myself

12. Motivation:

Answer: give breaks and take time to do things I enjoy

13. Obstacles:

Answer: leaving things last minute

14. Solutions:

Answer: planning to do certain things before a certain day

This can be for any of those goals

Personal Enrichment Goal

15. My personal enrichment goal is:

Answer: Stay healthy

16. My action steps are:

Answer: eat healthier foods

17. My time frame is:

Answer: now to the end of the school year

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Answer: I don't make a big deal out of eating veggies and stuff

19. Motivation:

Answer: treat myself every so often

20. Obstacles:

Answer: Craving junk food

21. Solutions:

Answer: find a way to make healthier foods taste similar to junk food (EX. Put cheese on broccoli)

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3 years ago

Describe the phenomenon of photoelectric emission ​

Describe the phenomenon of photoelectric emission