Electricity: Class 10 Science Q&A · Page 13
281 free answers on Electricity (Science) for Class 10 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- ScienceClass 10ICSE
The work done in moving a unit charge across two points in an electric circuit is a measure of: a) Current b) Potential difference c) Resistance Power
The correct option is b) Potential difference. Potential difference is the measure of the work done in moving a unit charge across two points in an electric circuit.
- ScienceClass 10ICSE
Name a device that helps to measure the potential difference across a conductor. b) How much energy is transferred by a 12V power supply to each coulomb of charge which it moves around a circuit?
Voltmeter Given, Potential difference = 12V Charge moved = 1C Work done = ? We know that the work done is given as: Work done = Potential difference × Charge moved = 12 × 1 = 12 Joules Therefore, 12J work is done on a 1C charge.
- ScienceClass 10ICSE
State the relation between potential difference, work done, and charge moved. b) Calculate the work done in moving a charge of 4 Coulomb from a point at 220 Volts to another point at 230 Volt.
Potential difference = (Work done)/(Charge moved) Given, V1 = 220V V2 = 230V Charge moved = 4C Potential difference = ? We know that potential difference is: Potential difference = V2 – V1 = 230 – 220 = 10 Work done = Potential difference × charge moved = 10 × 4 = 40J Therefore, the work done is 40J to move charges.
- ScienceClass 10ICSE
What do you understand by the term “electric potential” at a point? What is the unit of electric potential?
The electric potential at a point is defined as the work done to move a unit positive charge from infinity to a particular point. Volt is the unit of electric potential.
- ScienceClass 10ICSE
Which of the following are conductors and which are insulators? Sulphur, silver, copper, cotton, aluminium, air, nichrome, graphite, paper, porcelain, mercury, mica, Bakelite, polythene, manganin
Conductor: Silver, copper, aluminium, nichrome, graphite, mercury, manganin Insulator: Sulphur, cotton, air, paper, porcelain, mica, Bakelite, polythene
- ScienceClass 10ICSE
What is meant by conductors and insulators? Give two examples of conductors and two of insulators.
Conductors are defined as the materials through which electric current can flow. Almost all the metals are examples of conductors. Following are the examples of conductors: Copper, silver Insulators are defined as the materials through which electric current cannot flow. Non-metals are examples of insulators. Following are the examples of insulators: Plastic, cotton
- ScienceClass 10ICSE
Fill in the following blanks with suitable words: a) Potential difference is measured in …………… by using a ……….. placed in across a component. Copper is a good ……….. plastic is an …………….
Volts, voltmeter, parallel Conductor, insulator
- ScienceClass 10ICSE
Define one coulomb charge.
One coulomb charge is defined as the quantity of charge that exerts a force of 9 × 109 Newton on a charge which is placed at a distance of 1m from it.
- ScienceClass 10ICSE
What is the unit of electric charge?
Coulomb is the unit of electric charge. Coulomb is defined as the charged that is transferred with the help of a steady current of one ampere in one second.
- ScienceClass 10ICSE
How much work is done in moving a charge of 2C across two points having a potential difference of 12V?
Given, Potential difference = 12V Charge moved = 2C To find, Work done = ? We know that the work done is given as: Work done = p.d × charge moved = 12 × 2 = 24J Therefore, 24J of work is done to move a charge of 2C with a potential difference of 12V.
- ScienceClass 10ICSE
What is the SI unit of potential difference?
The SI unit of potential difference is volt. It is the difference of potential that one ampere of current is carried against one-ohm resistance.
- ScienceClass 10ICSE
How much work is done when one-coulomb charge moves against a potential difference of 1 volt?
Given, Potential difference = 1V Charge to be moved = 1C To find, Work done = ? We know that the work done is given as: Work done = Potential difference × Charge moved = 1 × 1 = 1J Therefore, 1J of work is done to move 1C charge with 1V potential difference.
- ScienceClass 10ICSE
What is meant by saying that the electric potential at a point is 1 volt?
The electric potential at a point is 1 volt means 1 joule of work is done in moving 1 unit of positive charge from infinity to that particular point.
- ScienceClass 10ICSE
a) What do the letters p.d stand for? b) Which device is used to measure p.d?
d stands for potential difference Potential difference is defined as the difference between the energy carried by the two points in the circuit. Potential difference is also equal to the product of the amount of current and the resistance. Following is the formula used for calculating potential difference: V = I × R Where, V is the voltage I is the current R is the resistance Voltmeter is
- ScienceClass 10ICSE
Which of the following statements correctly defines a volt? a) A volt is a joule per ampere A volt is a joule per coulomb
The correct statement that defined a volt is b) A volt is a joule per coulomb Volt is a joule per coulomb because joule is a unit of work done while coulomb is a unit for the charge. The ratio of work done to the charge is the definition of potential and volt is the unit of potential difference. Therefore, it can be said that one joule per coulomb is equal to the unit of the potential difference which is also equal to one volt. (1 Joule)/(1Coulomb) = 1Volt
- ScienceClass 10ICSE
By what other name is the unit joule/coulomb called?
The other name of the unit joule/coulomb is volt. Volt is the SI unit of electric potential or of electromotive force. It is represented by the letter V. Volt is a representation of the potential difference between the two points of a current-carrying wire of 1 ampere such that when the power dissipates between these two points, it is equal to 1 watt.
- ScienceClass 10CBSE
Explain the following. a. Why is the tungsten used almost exclusively for filament of electric lamps? b. Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal? c. Why is the series arrangement not used for domestic circuits? d. How does the resistance of a wire vary with its area of cross-section? e. Why copper and aluminium wires are usually employed for electricity transmission?
Solution: The resistivity and melting point of tungsten is very high. Due to this property, it doesn’t burn readily when heated. Electric lamps operate at high temperature. Hence, tungsten is a choice of metal for the filament of electric lamps. The conductors of electric heating devices are alloys because of their high resistivity. Alloys have higher resistivity than pure metals. Due to its high resistivity, a large amount of heat is produced when current passe
- ScienceClass 10CBSE
An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.
Solution: The rate at which the heat develops in the heater can be calculated using the following formula P = I2 R Substituting the values in the equation, we get P = (15A) 2 × 8 Ω = 1800 watt The electric heater produces heat at the rate of 1800 watt
- ScienceClass 10CBSE
Which uses more energy, a 250 W TV set in 1 hr, or a 1200 W toaster in 10 minutes?
Solution: The energy consumed by electrical appliances is given by the equation H = Pt, where P is the power of the appliance and t is the time Using this formula, the energy consumed by a TV of power ration 250 W, can be calculated as follows: H = 250 W × 3600 seconds = 9 × 105 J Similarly, the energy consumed by a toaster of power rating 1200 W is H =
- ScienceClass 10CBSE
How is a voltmeter connected in the circuit to measure the potential difference between two points?
Solution: To measure the voltage between any two points, the voltmeter should be connected in parallel between the two points.