Anonymous

Who invented TVs?

Tue, Aug 2023

Gemini

Philo Farnsworth

ChatGPT 4

The invention of the television was the work of many inventors over several decades. However, the credit for its practical use is often given to two inventors: Vladimir Zworykin and Philo Farnsworth.

Vladimir Zworykin, a Russian-born American inventor, is often credited as a father of television. He invented the iconoscope (a type of cathode-ray tube) in 1923, which was used as a transmission tube in early television systems.

Philo Farnsworth, an American inventor, is also considered a pioneer of television technology. In 1927, at the age of 21, he produced the first all-electronic television image. He also developed the "image dissector", which could capture and transmit images as an electronic signal.

It's important to note that these inventions were built upon previous work by other inventors and scientists in fields such as electromagnetism and radio waves. The development of television was a complex process that involved numerous innovations and contributions from many individuals across different countries and periods.

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What are the properties of resistors?

what are the properties of resistors?

Tue, Mar 2024

Gemini

There are four main properties of resistors: resistance, resistivity, conductance, and conductivity.

Resistance is the measure of the opposition to current flow in an electrical circuit. It is expressed in ohms (Ω). The resistance of a resistor is determined by its length, cross-sectional area, and resistivity.

Resistivity is the measure of the intrinsic resistance of a material to the flow of electrical current. It is expressed in ohms per meter (Ω·m). The resistivity of a material is determined by its atomic structure and composition.

Conductance is the measure of the ability of a material to conduct electrical current. It is expressed in siemens (S). The conductance of a material is the reciprocal of its resistance.

Conductivity is the measure of the ability of a material to conduct electrical current per unit area. It is expressed in siemens per meter (S/m). The conductivity of a material is the reciprocal of its resistivity.

The following table summarizes the four properties of resistors:

| Property | Symbol | Unit | Formula | |---|---|---|---| | Resistance | R | Ω | $\frac{V}{I}$ | | Resistivity | ρ | Ω·m | $\frac{RA}{l}$ | | Conductance | G | S | $\frac{1}{R}$ | | Conductivity | σ | S/m | $\frac{1}{\rho}$ |

where:

V is the voltage across the resistor
I is the current flowing through the resistor
R is the resistance of the resistor
ρ is the resistivity of the material
A is the cross-sectional area of the resistor
l is the length of the resistor

Resistors are used in a variety of electrical circuits to control the flow of current. They can be used to:

Limit the current flow in a circuit
Divide the voltage in a circuit
Convert AC to DC
Provide a path for current to flow in a circuit

Resistors are essential components in any electrical circuit. They are used in everything from simple electronic devices like flashlights and radios to complex machines like computers and automobiles.

ChatGPT 4

Resistors are fundamental components of electrical and electronic circuits. They have several properties that make them essential in these circuits:

Resistance: The primary property of a resistor is its resistance, which is measured in ohms (Ω). This property determines how much the resistor will resist or oppose the flow of electric current through it. The higher the resistance, the less current will flow for a given applied voltage.

Tolerance: This refers to the accuracy of the resistor's value, usually expressed as a percentage. For example, a 100Ω resistor with a tolerance of 5% could actually have a resistance between 95Ω and 105Ω.

Power Rating: This is the maximum amount of power that a resistor can dissipate without overheating and potentially failing. It is typically measured in watts (W). The power rating depends on the physical size of the resistor; larger resistors can usually dissipate more power.

Temperature Coefficient: This property describes how much the resistance changes with temperature. Some materials have positive temperature coefficients (resistance increases with temperature), while others have negative coefficients (resistance decreases with temperature).

Noise: All resistors generate some amount of electrical noise, which can interfere with signals in a circuit. The amount and type of noise depend on the material used to make the resistor and its construction.

Stability and Reliability: Over time, a resistor's value may drift due to aging or environmental factors like humidity and temperature changes. High-quality resistors are designed to minimize this drift and maintain their specified resistance value over their lifetime.

Frequency Response: Some types of resistors may not behave as pure resistances at high frequencies due to parasitic capacitance or inductance effects.

Voltage Rating: This is the maximum voltage that can be applied across a resistor without causing damage or failure.

Size and Form Factor: Resistors come in a variety of sizes and shapes, from tiny surface-mount devices to large wirewound power resistors. The size and form factor often depend on the intended application of the resistor.

Material: Resistors can be made from a variety of materials, including carbon, metal film, metal oxide, and wirewound. The material used can affect many of the properties listed above.

Claude AI

Here are the main properties of resistors:

Resistance: Resistors are designed to have a specific amount of resistance to the flow of electric current, measured in ohms (Ω). The resistance value determines how much the resistor limits the current flow in a circuit.

Power rating: Resistors are rated for the maximum amount of power they can dissipate without being damaged, measured in watts (W). The power rating is determined by the resistor's size and construction.

Tolerance: Resistors have a tolerance value, which is the deviation from the nominal resistance value, expressed as a percentage. Common tolerances are ±1%, ±5%, and ±10%. Tighter tolerances are more precise but also more expensive.

Temperature coefficient: The resistance of a resistor can change with temperature. The temperature coefficient is a measure of how much the resistance changes per degree of temperature change, expressed in parts per million per degree Celsius (ppm/°C).

Noise: Some resistors generate electrical noise due to the thermal agitation of electrons. This noise is usually negligible in most applications but can be critical in sensitive circuits.

Voltage coefficient: The resistance of some resistors can change with the applied voltage. This effect is typically more pronounced in high-voltage applications.

Frequency response: The resistance of a resistor can change with the frequency of the applied signal. This property is essential in high-frequency applications, such as radio and television circuits.

Size and package: Resistors come in various sizes and packages, such as through-hole, surface-mount, and wire-wound. The size and package determine the resistor's power rating, heat dissipation capabilities, and ease of use in different circuit layouts.

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Janetteja

What’s the difference between the following voltages electromotive force , Voltage drop , potential difference and terminal voltage?

what’s the difference between the following voltages electromotive force , Voltage drop , potential difference and terminal voltage

Tue, Mar 2024

Gemini

Electromotive force (emf) is the energy per unit charge that is imparted to the charges as they move through a circuit. It is measured in volts (V).

Voltage drop is the difference in electric potential between two points in a circuit. It is measured in volts (V).

Potential difference is the same as voltage drop. It is the difference in electric potential between two points in a circuit. It is measured in volts (V).

Terminal voltage is the voltage measured across the terminals of a battery or other power source. It is equal to the emf of the source minus the voltage drop across the internal resistance of the source. It is measured in volts (V).

Here is a table summarizing the differences between these four terms:

| Term | Definition | Unit | |---|---|---| | Electromotive force (emf) | The energy per unit charge that is imparted to the charges as they move through a circuit | Volts (V) | | Voltage drop | The difference in electric potential between two points in a circuit | Volts (V) | | Potential difference | The same as voltage drop | Volts (V) | | Terminal voltage | The voltage measured across the terminals of a battery or other power source | Volts (V) |

ChatGPT 4

Electromotive Force (EMF): This is the maximum potential difference between two points in a circuit. It is the total energy provided by a cell or battery per coulomb of charge. It's essentially the 'push' that moves electrons around a circuit, causing current to flow. EMF is not actually a force, despite its name; it's measured in volts.

Voltage Drop: This refers to the decrease in electrical potential along the path of a current flowing in an electrical circuit. Voltage drops in an electrical circuit can be calculated using Ohm's law (V=IR), where V is the voltage drop, I is the current in amperes, and R is the resistance in ohms.

Potential Difference: This term refers to the work done to move a unit positive charge from one point to another in an electric field. It's essentially the difference in electric potential between two points and can exist between any two points, not just those within a power source. Like EMF and voltage drop, potential difference is also measured in volts.

Terminal Voltage: This refers to the voltage output of a device such as a battery or generator. The terminal voltage of a device can be calculated by subtracting the internal resistance of the device from its EMF. When no current flows, terminal voltage equals EMF; when current flows, terminal voltage is less than EMF due to internal resistance.

In summary, while all these terms refer to different aspects of electrical potential and are measured in volts, they apply to different parts of an electrical system and are used under different circumstances.

Claude AI

Here's an explanation of the differences between electromotive force, voltage drop, potential difference, and terminal voltage:

1. Electromotive Force (EMF):
- EMF is the voltage generated by a source of electrical potential difference, such as a battery or a generator.
- It is the force that causes electrons to flow through a circuit.
- EMF is measured in volts (V) and is represented by the symbol ε (epsilon).

2. Voltage Drop:
- Voltage drop is the decrease in voltage across a component or a section of a circuit due to the resistance of that component or section.
- It occurs when current flows through a resistive element, causing a dissipation of energy in the form of heat.
- The voltage drop across a component is equal to the product of the current flowing through it and its resistance (Ohm's law: V = IR).

3. Potential Difference:
- Potential difference, also known as voltage, is the difference in electric potential energy per unit charge between two points in an electrical circuit.
- It is the force that drives electric current through a conductor.
- Potential difference is measured in volts (V) and is represented by the symbol V or ΔV.
- In a closed circuit, the sum of all potential differences around the circuit is equal to the EMF of the source.

4. Terminal Voltage:
- Terminal voltage is the voltage measured across the terminals of a source or a load in a circuit.
- It is the potential difference between the positive and negative terminals of a battery or any other electrical component.
- Terminal voltage is affected by the load connected to the source and the internal resistance of the source.
- When a load is connected, the terminal voltage is always less than the EMF due to the voltage drop across the internal resistance of the source.

In summary, EMF is the voltage generated by a source, voltage drop is the decrease in voltage across a component due to resistance, potential difference is the difference in electric potential energy between two points, and terminal voltage is the voltage measured across the terminals of a source or load in a circuit.

                                                

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bili85303

Who designed the waste rock dams?

Mon, Dec 2023

Gemini

Geotechnical engineers

ChatGPT 4

The question does not provide specific information about which waste rock dams are being referred to. Waste rock dams can be found in many places around the world, and they are typically designed by teams of engineers who specialize in geotechnical, civil, or environmental engineering. These professionals may work for private engineering firms, mining companies, or government agencies. The design process involves careful consideration of factors like the type of waste material, the local environment, and safety regulations.
                                                

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bili32222

Who designed the concrete barriers?

Wed, Nov 2023

Gemini

Edward Teller

ChatGPT 4

The design of concrete barriers, specifically the Jersey barrier or Jersey wall, is credited to the New Jersey State Highway Department. The original design was developed in the 1950s under the direction of William Gluck, a civil engineer working for the department. The purpose was to minimize vehicle damage in accidents and reduce the likelihood of cars crossing into oncoming lanes.

However, it's important to note that there are various types of concrete barriers used worldwide today, each with different designs and purposes. These include K-rails (California), F-shape barriers, constant-slope barriers, vertical-face barriers and more. Each of these designs would have been developed by different engineers or organizations according to their specific needs and safety standards.

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Anonymous

How to become an astronaut?

Wed, Aug 2023

Gemini

There are a few things you need to do in order to become an astronaut.

First, you need to have a bachelor's degree in a STEM field, such as engineering, physics, or mathematics. You should also have a strong understanding of the physical sciences and math.

Next, you need to have at least 1,000 hours of pilot experience. This can be in either a civilian or military aircraft.

You also need to be in excellent physical condition. This includes being able to pass a rigorous physical exam and meet the height and weight requirements.

In addition, you need to be able to speak and understand English fluently.

Once you have met all of the above requirements, you can apply to the NASA astronaut training program. The program is highly competitive, and only a small number of applicants are accepted each year.

The astronaut training program lasts for two years and includes both classroom instruction and hands-on training. During the program, you will learn about space flight, spacecraft systems, and how to live and work in space.

If you successfully complete the astronaut training program, you will be assigned to a mission. You will then spend several years training for your mission.

Once you are ready for your mission, you will launch into space aboard a spacecraft. You will spend several days or weeks in space, conducting experiments and performing maintenance on the spacecraft.

After your mission, you will return to Earth and continue your work with NASA. You may also be asked to speak to the public about your experience as an astronaut.

Becoming an astronaut is a challenging but rewarding career. It is a chance to explore space and to make a difference in the world.

ChatGPT 4

Becoming an astronaut is not an easy task and requires a combination of education, experience, and physical fitness. Here are the steps you need to take:

1. Obtain the Necessary Education: The first step to becoming an astronaut is getting a solid education. NASA requires that all astronaut candidates have at least a bachelor's degree in engineering, biological science, physical science, computer science or mathematics from an accredited institution. Many astronauts also have advanced degrees.

2. Gain Relevant Experience: After obtaining the necessary education, you need to gain professional experience in your field. For non-pilots, NASA requires at least three years of related professional experience or at least 1,000 hours of pilot-in-command time in jet aircraft.

3. Apply to NASA: Once you meet the educational and experiential requirements, you can apply to become an astronaut candidate through USAJobs.gov when NASA has a call for applications (which is not always open). The application process includes submitting your resume and references.

4. Pass the Astronaut Physical: If your application is accepted, you will be invited to take a long-duration spaceflight physical exam. This includes vision tests (correctable to 20/20 in each eye), blood tests, and heart tests.

5. Complete Astronaut Training: If you pass the physical exam and are selected as an astronaut candidate by NASA's Astronaut Selection Board, you will then undergo about two years of training at the Johnson Space Center in Houston, Texas. This training includes swimming tests (since astronauts must be able to swim in their suits), military water survival training, scuba diving training (to simulate spacewalks), robotics skills training, Russian language training (since many missions go through Russia), aircraft flight readiness training and more.

6. Get Selected for a Mission: After completing your training successfully, you will be eligible for selection for a space mission.

7. Go to Space: Once selected for a mission, there will be additional specific mission training before finally going into space.

It's important to note that becoming an astronaut is highly competitive; thousands apply each time NASA has a call for applications but only a handful are selected.
  
In addition to these steps above which are specific for NASA (USA), other countries have their own space agencies with similar but possibly slightly different requirements.
  
Also worth noting that private companies like SpaceX are now also selecting astronauts outside traditional government programs.
  
Finally remember that being an astronaut requires not just technical skills but also teamwork skills and ability to stay