Physics Derived Units and Multipliers

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Questions and Answers

What is the SI unit of force?

Pascal

Watt

Newton (correct)

Joule

How is one newton defined in terms of basic units?

m/s2

kg/s2

kg m/s

kg m/s2 (correct)

What unit is used to measure pressure in the SI system?

Joule

Tesla

Watt

Pascal (correct)

Which of the following is the alternative unit for energy?

Newton meter Signup and view all the answers

What is the derived unit for electric potential?

Volt Signup and view all the answers

What is the unit of magnetic flux density?

Tesla Signup and view all the answers

Which prefix corresponds to a factor of $10^{-6}$?

micro Signup and view all the answers

Which of the following is not a derived unit in the SI System?

Kilogram Signup and view all the answers

What is a fixed point in the context of temperature measurements?

An arbitrarily chosen standard system temperature that is easily reproducible Signup and view all the answers

Which two fixed points existed before 1954 for temperature measurement?

The ice point and the steam point Signup and view all the answers

How can the temperature interval θ(1) − θ(2) be quantified?

Using the values of θ(1) and θ(2) measured directly Signup and view all the answers

What does the equation θ( ) = θ(1) ⋅ (θ( ) – θ(2)) imply?

It describes the relationship between temperature intervals Signup and view all the answers

What conditions must exist at the ice point to define it as a fixed point?

Pure water in equilibrium with saturated air at one atmosphere pressure Signup and view all the answers

Which of the following statements is true regarding water wheels and their work output?

Water must enter and exit the wheel for work output. Signup and view all the answers

What does the maximum efficiency of a steam engine depend on?

The temperature difference between energy reservoirs. Signup and view all the answers

What is a fundamental conclusion from Carnot's work with heat engines?

There is always a loss of energy due to mechanical friction. Signup and view all the answers

Who is credited with coining the term 'second law of thermodynamics'?

Rudolf Clausius Signup and view all the answers

Which of the following best describes Carnot’s cycle?

A thermodynamic cycle with two isothermal and two adiabatic processes. Signup and view all the answers

What was the outcome of Sadi Carnot's work after his death?

His work remained unrecognized until decades later. Signup and view all the answers

Which scientist strengthened Carnot's ideas with precise mathematical derivations?

Emile Clapeyron Signup and view all the answers

What significant concept did William Thomson develop based on Carnot's conclusions?

Absolute temperature scale. Signup and view all the answers

What does Mayer’s equation express a relationship between?

Specific heats of an ideal gas Signup and view all the answers

What key discovery did Joule make regarding the flow of electric current?

It creates heat proportional to resistance Signup and view all the answers

What is the general relation that forms the core of Joule's experiments?

W = JQ Signup and view all the answers

How was Joule's initial presentation of his findings received by the scientific community?

It faced skepticism and silence Signup and view all the answers

What did Joule use to demonstrate his experiments on heat development?

Paddle wheels in water Signup and view all the answers

What phenomenon did Joule suggest regarding the temperature of water at the bottom of Niagara Falls?

It should be warmer than at the top Signup and view all the answers

What does the variable J represent in Joule's relation W = JQ?

The mechanical equivalent of heat Signup and view all the answers

Which of the following best describes the historical context of Joule's work?

It built on the work of previous scientists like Rumford Signup and view all the answers

What is the significance of a quasi-static process in thermodynamics?

It proceeds infinitely slowly, allowing the system to remain in equilibrium. Signup and view all the answers

Which of the following defines density in the context of continuum mechanics?

Mass per unit volume of a material. Signup and view all the answers

How is the mass flow rate of a liquid calculated given the discharge rate?

By multiplying discharge rate by the density of the liquid. Signup and view all the answers

What is the purpose of a pressure transducer?

To convert pressure into a measurable electrical signal. Signup and view all the answers

Given the equation $pv^{1.4} = 2.3 × 10^{3}$, what does the variable $v$ represent?

Specific volume in m³/kg. Signup and view all the answers

What is the depth of atmosphere necessary to produce a pressure of 1.0132 bar, if the calculated depth is 64.8 km?

64.8 km. Signup and view all the answers

What is the estimated steam pressure in kPa if a mercury manometer shows a reading of 76.1 cm Hg?

101.3 kPa. Signup and view all the answers

How does the acceleration of gravity change with elevation according to the given equation $g = 980.6 - 3.086 × 10^{-6} H$?

It decreases as elevation increases. Signup and view all the answers

Study Notes

Derived Units

Force is measured in Newtons (N) which is equal to kg m/s^2
Energy is measured in Joules (J) which is equal to kg m^2/s^2
Power is measured in Watts (W) which is equal to kg m^2/s^3
Pressure is measured in Pascals (Pa) which is equal to kg/(ms^2)
Frequency is measured in Hertz (Hz) which is equal to s^-1
Electric charge is measured in Coulombs (C) which is equal to As
Electric potential is measured in Volts (V) which is equal to kg m^2/(s^3 A)
Capacitance is measured in Farads (F) which is equal to s^4 A^2/(kg m^2)
Electrical resistance is measured in Ohms (Ω) which is equal to kg m^2/(s^3 A^2)
Magnetic flux is measured in Webers (Wb) which is equal to Vs
Magnetic flux density is measured in Tesla (T) which is equal to Wb/m^2
Inductance is measured in Henrys (H) which is equal to Wb/A

Standard Multipliers

Tera (T) is equal to 10^12
Giga (G) is equal to 10^9
Mega (M) is equal to 10^6
Kilo (k) is equal to 10^3
Milli (m) is equal to 10^-3
Micro (μ) is equal to 10^-6
Nano (n) is equal to 10^-9
Pico (p) is equal to 10^-12

Force

Force acting on a body is defined by Newton's second law of motion
One Newton of force produces an acceleration of 1 ms^-2 when applied to a 1 kg mass
Weight of a body is the force of attraction to the center of Earth
Weight is calculated by multiplying mass and local gravitational acceleration

Mayer's Equation

The relationship between specific heats of an ideal gas is called Mayer's Equation
Mayer's Equation describes the difference between the specific heats at constant pressure and constant volume (c_p - c_v) which is equal to R.

Joule's Experiments

Joule observed the relationship between current flow, resistance, and heat generation
He concluded that caloric was created through current flow
He recognized a universal conservation law of energy
He determined the mechanical equivalent of heat (W = JQ)
His experiments showed the universal validity of energy conversion
He demonstrated that the conversion of energy forms is governed by definite conversion factors
He conducted famous experiments with paddle wheels in a water pool driven by falling weights
He argued that the water at the bottom of Niagara Falls should be warmer by 0.2°F due to energy conversion

Water Wheels and Heat Engines

Water wheels cannot convert all energy of inlet water into shaft work output
There must be an outflow of water with lower energy from the wheel
This concept is extended to heat engines where caloric enters at high energy and exits at low energy
Continuous conversion of all caloric input into work output is impossible, leading to the Kelvin-Planck statement of the second law of thermodynamics

Carnot's Work

Carnot studied the maximum efficiency of water wheels and heat engines.
He concluded that the maximum efficiency of a water wheel depends on the inlet and outlet flow energies.
The maximum efficiency of a heat engine depends on the high and low temperature thermal reservoirs, independent of the working fluid
The maximum efficiency is achieved with no mechanical friction or losses.

Thermodynamics History

Carnot's work was not recognized until 1850
Clausius and Thomson developed the conservation of energy principle
Carnot's first conclusion was called the second law of thermodynamics
Carnot's second conclusion led to the development of the absolute temperature scale
Thermodynamics originated from early steam engines.
Carnot's ideas were largely ignored until Clapeyron clarified them with mathematical derivation.

Carnot's Cycle

Clapeyron understood the Carnot cycle with two reversible isothermal and two reversible adiabatic processes.
The Carnot cycle was the first heat engine cycle.

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Description

Test your understanding of derived units in physics along with their standard multipliers. This quiz covers essential units like Newtons, Joules, and their respective relationships. Perfect for students preparing for exams in physics.