Electricity: Class 10 Science Q&A · Page 11
281 free answers on Electricity (Science) for Class 10 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- ScienceClass 10ICSE
State the factors on which the strength of electric current flowing in a given conductor depends.
Following are the factors on which the strength of electric current flowing in a given conductor depends: Voltage (or potential difference) across the ends of the conductor Resistance offered by the conductor
- ScienceClass 10ICSE
Keeping the resistance constant, the potential difference applied across the ends of a component is halved. By how much does the current change?
Given, Resistance = constant We know that V = IR When resistance, R is constant, V is proportional to I Therefore, when V is halved, I also becomes half.
- ScienceClass 10ICSE
What is the general name of the substances having infinitely high electrical resistance?
Insulators are the substances that are having infinitely high electrical resistance.
- ScienceClass 10ICSE
Name the physical quantity whose unit is “ohm”.
The physical quantity whose unit is “ohm” is electric resistance.
- ScienceClass 10ICSE
Name the unit of electrical resistance and give its symbol.
The unit of electrical resistance is Ohm. Following is the symbol of ohm: Ω
- ScienceClass 10ICSE
Name the law which relates the current in a conductor to the potential difference across its ends. Answer:
The law that relates the current in a conductor to the potential difference across its ends is Ohm’s law.
- ScienceClass 10ICSE
How many electrons are flowing per second past a point in a circuit in which there is a current of 5A?
Given, Current, I = 5A Time taken, t = 1s We know that, I = Q/t Q = I × t = 5 × 1 = 5C Number of electrons present in 1.6 × 10-19C = 1 Number of electrons present in 5C = (5)/( 1.6 × 10-19) = 31.25 × 1018 C
- ScienceClass 10ICSE
An electric heater is connected to the 230V mains supply. A current of 8A flows through the heater. a) How much charge flows around the circuit each second? How much energy is transferred to the heater each second?
Given, Potential difference = 230V Current, I = 8A I = Q/t 8 = Q/1 Q = 8 × 1 = 8C Therefore, the charge flow around the circuit for every second is 8C. We know that energy transferred = work done Potential difference = work done/charge moved 230 = work done/8 Therefore, work done = 230 × 8 = 1840J
- ScienceClass 10ICSE
If the amount of electric charge passing through a conductor in 10 minutes is 300C, the current flowing is: a) 30A b) 0.3A c) 0.5A d) 5A
Given, Charge moved = 300C Time taken = 10 mins Current = ? I = Q/t Substituting, we get I = 0.5A Therefore, the correct option is c) 0.5A
- ScienceClass 10ICSE
If the current through a flood lamp is 5A, what charge passes in 10 seconds? a) 0.5C b) 2C c) 5C d) 50C
Given, Current, I = 5A Time taken, t = 10s Charge moved, Q = ? I = Q/t Q = I × t Q = 50C Therefore, the correct option is d) 50C
- ScienceClass 10ICSE
Which unit could be used to measure current? a) Watt b) Coulomb c) Volt Ampere
The correct option that could be used to measure current unit is d) Ampere
- ScienceClass 10ICSE
Which statement/statements is/are correct? a) An ammeter is connected in series in a circuit and a voltmeter is connected in parallel b) An ammeter has a high resistance A voltage has a low resistance
The correct statement is a) An ammeter is connected in series in a circuit and a voltmeter is connected in parallel
- ScienceClass 10ICSE
The other name of potential difference is a) Ampereage b) Waltage c) Voltage Potential energy
The other name of potential difference is c) Voltage
- ScienceClass 10ICSE
Define electric current. What is the SI unit of electric current. b) One coulomb of charge flows through any cross-section of a conductor in 1 second. What is the current flowing through the conductor? c) Which instrument is used to measure electric current? How should it be connected in a circuit? d) What is the conventional direction of the flow of electric current? How does it differ from the direction of flow of electrons? e) A flash of lightning carries 10C of charge which flows for 0.01s. What is the current? If the voltage is 10MV, what is the energy?
The flow of electric charges or electrons in a conductor such as a metal wire is known as electric Ampere is the SI unit of electric charges. The current flowing through the conductor when one coulomb of charge flows through any cross-section of a conductor in 1 second is 1 ampere. For the measurement of electric current, an ammeter is used which is connected in series in the The direction of conventional direction of
- ScienceClass 10ICSE
In 10s a charge of 25C leaves a battery and 200J of energy are delivered to an outside circuit as a result. a) What is the potential difference across the battery? What current flows from the battery?
Given, Time taken, t = 10s Charge moved, Q = 25C Energy delivered is work done = 200J Potential difference = (work done)/(charge moved) = (200)/(25) = 8V I = Q/t = 25/10 = 5A
- ScienceClass 10ICSE
The potential difference across a lamp is 12V. How many joules of electrical energy are changed into heat and light when: a) a charge of 1C passes through it? b) a charge of 5C passes through it? a current of 2A flows through it for 10s?
Given, Potential difference = 12V Potential difference = (work done)/(charge moved) Work done = Potential difference × charge moved = 12 × 1 = 12J Therefore, 12J of electrical energy is converted into heat and light. Work done = potential difference × charge moved = 12 × 5 = 60J Therefore, 60J of electrical energy is converted into heat and light. I = Q/t Q = I &tim
- ScienceClass 10ICSE
If the charge on an electron is 1.6 × 10-19 coulombs, how many electrons should pass through a conductor in 1 second to constitute 1 ampere current?
Given, Charge moved = 1.6 × 10-19 coulombs Current, I = 1A Time taken, t = 1s We know that, I = Q/t 1 = Q/1 Q = 1C We also know that when the charge is 1.6 × 10-19 coulombs, the number of electrons present is 1 Therefore, when a charge of 1 coulomb is present, the number of electrons is given as: (1)/( 1.6 × 10-19) = 0.625 × 10-19 = 6.25 × 1018
- ScienceClass 10ICSE
Write down the formula which relates electric charge, time, and electric current. b) A radio set draws a current of 0.36A for 15 minutes. Calculate the amount of electric charge that flows through the circuit.
The relation between electric charge, time, and electric current is given as: Current = (charge moved)/(time) While work done = potential difference × charge moved Therefore, above is the relation between electric, time, and electric current Given, Current, I = 0.36A Time taken, t = 15 min = 900s We know that, Q = I × t = 0.36 × 900 = 324C Therefore, 324C charge fl
- ScienceClass 10ICSE
What is an electric current? What makes an electric current flow in a wire? b) Define the unit of electric current.
An electric current is defined as the flow of electric charges through a conductor such that the potential difference between the two points in the conductor is responsible for the flow of electric current. Ampere is the unit of electric It is defined as 1 coulomb of charge flowing through a cross-section of a conductor in 1 second such that the electric current flowing through the conductor is 1 ampere.
- ScienceClass 10ICSE
Name a device which helps to maintain potential difference across a conductor (say a bulb). b) If a potential difference of 10V causes a current of 2A to flow for 1 minute, how much energy is transferred?
Given, Potential difference = 10V, Current, I = 2A Time taken, t = 60s We know that: I = Q/t So, Q = I×t Substituting the values, we get Q = 2 × 60 = 120 Therefore, charge moved is 120C We also know that, Work done = Potential difference × charge moved = 120 × 10 =1200J Therefore, work done to move a charge of 120C is 1200J.