To a steel conductor length $80\,\text{sm}$ and cross section $0{,}15\,\text{mm}^{2}$ on $1\,\text{min}$ applied voltage $1{,}2\,\text{V}$. Resistivity $0{,}12\,\text{Om}\cdot\text{mm}^{2}/\text{m}$. Define resistance, current, power, work, heat and charge.

R = 0{,}64\,\text{Ohm}; I = 1{,}875\,\text{A}; P = 2{,}25\,\text{W}; A = 135\,\text{J}; Q = 135\,\text{J}; q = 112{,}5\,\text{Cl}

To the source with EMF $4{,}5\,\text{V}$ and internal resistance $2\,\text{Om}$ connect the resistor for a minute $7\,\text{Om}$. Determine load current, voltage, power, work, heat, charge and number of electrons.

I = 0{,}5\,\text{A}; U = 3{,}5\,\text{B}; P = 1{,}75\,\text{W}; A = 105\,\text{J}; Q_1 = 105\,\text{J}; q = 30\,\text{Cl}; n = 1{,}875\cdot 10^{20}

Under tension $3{,}2\,\text{V}$ the current in the circuit is $0{,}5\,\text{A}$, and when $2{,}6\,\text{V}$ - $1\,\text{A}$. Determine the emf and internal resistance of the source.

\varepsilon = 3{,}8\,\text{B}; r = 1{,}2\,\text{Ohm}

Conduction electron concentration in germanium at room temperature $3\cdot10^{19}\,\text{m}^{-3}$. What proportion of the total number of atoms are conduction electrons? Density $5400\,\text{kg/m}^{3}$, molar mass $0{,}073\,\text{kg/mol}$.

\dfrac{n}{N} = 6{,}76\cdot 10^{-10}

How much aluminum will be released per day under current $140\,\text{kA}$ and voltage $4\,\text{V}$? What is the energy consumption? Electrochemical equivalent $0{,}093\cdot10^{-6}\,\text{kg/Kl}$.

m = 1125\,\text{kg}; A = 4{,}84\cdot 10^{10}\,\text{J}

Voltmeter on $6\,\text{V}$ has internal resistance $600\,\text{Om}$. How to extend the measurement limit to $30\,\text{V}$?

R_{\text{д}} = 2400\,\text{Ohm}

The ammeter is designed for $2\,\text{A}$ and has internal resistance $0{,}4\,\text{Om}$. How to extend the measurement limit to $10\,\text{A}$?

R_{\text{ш}} = 0{,}1\,\text{Ohm}

A light bulb $30\,\text{Vt}$, $40\,\text{V}$ needs to be connected to the network $220\,\text{V}$. What additional resistance should be connected in series?

R_{\text{д}} = 240\,\text{Ohm}

10TH GRADE PRACTICE

Physics Problems: Direct current, Grade 10

Laws of circuits, current operation and connections.

11 problems across 2 sub-topics

Practise in the interactive mode

Here the conditions and analysis of the solution can be read without an account. In the simulator, you need to collect the same analyzes yourself: “Given,” formulas, order of steps and answer.

Problem statements

The answer options are there to check against, and the walkthrough opens under each problem.

11 problems

Position in this set: 1 from 11

Problem #106

Direct current: Ohm's law and resistance

To a steel conductor length and cross section on applied voltage . Resistivity . Define resistance, current, power, work, heat and charge.

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Given

Find

All work done by the current on the resistor turns into heat.

Answer

Position in this set: 2 from 11

Problem #107

Direct Current: Circuits, Operation and Power

To the source with EMF and internal resistance connect the resistor for a minute . Determine load current, voltage, power, work, heat, charge and number of electrons.

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Given

Find

Ohm's law for a complete circuit.
These are losses due to the internal resistance of the source.

Answer

Position in this set: 3 from 11

Problem #108

Direct current: Ohm's law and resistance

Resistance of aluminum conductor at equals . What will it be like , if ?

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Given

Find

First we find the resistance at zero degrees.

Answer

Position in this set: 4 from 11

Problem #109

Direct Current: Circuits, Operation and Power

Under tension the current in the circuit is , and when - . Determine the emf and internal resistance of the source.

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Given

Find

The source emf is the same in both modes.

Answer

Position in this set: 5 from 11

Problem #110

Direct Current: Circuits, Operation and Power

Conduction electron concentration in germanium at room temperature . What proportion of the total number of atoms are conduction electrons? Density , molar mass .

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Given

Find

This is the number of germanium atoms in one cubic meter.

Answer

Position in this set: 6 from 11

Problem #111

Direct Current: Circuits, Operation and Power

How much aluminum will be released per day under current and voltage ? What is the energy consumption? Electrochemical equivalent .

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Given

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Faraday's law of electrolysis.

Answer

Position in this set: 7 from 11

Problem #112

Direct Current: Circuits, Operation and Power

Voltmeter on has internal resistance . How to extend the measurement limit to ?

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Given

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The same current flows through the additional resistor as through the voltmeter.
The additional resistance is connected in series with the voltmeter.

Answer

Position in this set: 8 from 11

Problem #113

Direct Current: Circuits, Operation and Power

The ammeter is designed for and has internal resistance . How to extend the measurement limit to ?

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Given

Find

The shunt is connected in parallel, so the voltage is common.

Answer

Position in this set: 9 from 11

Problem #114

Direct Current: Circuits, Operation and Power

The crane motor operates under voltage and current . How long will it take him to lift a mass of to the height at efficiency ?

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Given

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Useful work is lifting a load, spent work is current work.

Answer

Position in this set: 10 from 11

Problem #115

Direct Current: Circuits, Operation and Power

A light bulb , needs to be connected to the network . What additional resistance should be connected in series?

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Given

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Answer

Position in this set: 11 from 11

Problem #116

Direct Current: Circuits, Operation and Power

It is necessary to make a heater with a power for voltage . What is the length of nichrome wire cross section needed when ?

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Given

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Answer

The theory behind these problems

Work through the topic if a problem will not give in.

Current, resistance and Ohm's lawCurrent strength and density, resistance, emf and Ohm's law.Current work and electrical circuitsWork, power, heat, electrolysis and resistor connections.

Formulas by topic

Look up symbols and units of measurement in the reference.

Efficiencyη · %PowerP, N · W WorkA · J Electrical resistanceR · Ohm Resistivityρ · Ohm m Electromotive forceε · B