Electricity: Class 10 Science Q&A · Page 10
281 free answers on Electricity (Science) for Class 10 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- ScienceClass 10ICSE
Keeping the potential difference constant, the resistance of a circuit is doubled. The current will become: a) Double b) Half c) One-fourth Four times
When the potential difference is constant and the resistance of a circuit is doubled, the current becomes half. Therefore, the correct option is b) half.
- ScienceClass 10ICSE
The substance having infinitely high electrical resistance is called: a) Conductor b) Resistor c) Superconductor Insulator
The correct option for the substance with infinitely high electrical resistance is called d) insulator.
- ScienceClass 10ICSE
The unit of electrical resistance is: a) Ampere b) Volt c) Coulomb Ohm
The correct option for the unit of electrical resistance is d) Ohm.
- ScienceClass 10ICSE
When a 4 Ω resistor is connected across the terminals of a 12V battery, the number of coulombs passing through the resistor per second is: a) 0.3 b) 3 c) 4 d) 12
The correct option that gives the relation in Ohm’s law is d) current and potential difference.
- ScienceClass 10ICSE
An electrical appliance has a resistance of 25 Ω. When this electrical appliance is connected to a 230 Ω supply line, the current passing through it will be: a) 0.92A b) 2.9A c) 9.2A d) 92A
The correct option is c) 9.2A
- ScienceClass 10ICSE
A car headlight bulb working on a 12V car battery draws a current of 0.5A. The resistance of the light bulb is: a) 0.5Ω b) 6 Ω c) 12 Ω d) 24 Ω
The correct option is d) 24 Ω
- ScienceClass 10ICSE
The potential difference across a 3Ω resistor is 6V. The current flowing in the resistor will be: a) ½ A b) 1A c) 2A d) 6A
The correct option is c) 2A.
- ScienceClass 10ICSE
What is the ratio of potential difference and current known as? b) The values of potential difference V applied across a resistor and the corresponding values of current I flowing in the resistor are given below: Potential difference, V in volts 2.5 5.0 10.0 15.0 20.0 25.0 Current, I in amperes 0.1 0.2 0.4 0.6 0.8 1.0 Plot a graph between V and I and calculate the resistance of the resistor. c) Name the law which is illustrated by the above V-I graph d) Write down the formula which states the relation between potential difference, current, and resistance e) The potential difference between the terminals of an electric iron is 240V and the current is 5.0A. What is the resistance of the electric iron?
The ratio of potential difference and the current is known as The law illustrated by the V-I graph is Ohm’s Following is the formula that states the relation between potential difference, current, and resistance: Potential difference = Current × Resistance Given, Voltage, V = 240 volt Current, I = 5 amp We know that V = IR 240 = 5 × R R = 240/5 = 48 o
- ScienceClass 10ICSE
Why do electricians wear rubber hand gloves while working with electricity? b) What potential difference is needed to send a current of 6A through an electrical appliance having a resistance of 40Ω?
We know that rubber is a good insulator or a bad conductor of This is the reason why electricians wear rubber hand gloves while working with electricity. Given, Current, I = 6A Resistance, R = 40Ω We know that, V = IR V = 6 × 40 = 240V
- ScienceClass 10ICSE
Define the unit of resistance. b) What happens to the resistance as the conductor is made thinner? c) Keeping the potential difference constant, the resistance of a circuit is doubled. By how much does the current change?
The unit of resistance is 1 ohm is defined as the resistance offered by the conductor such that when 1 volt potential difference is applied, then 1 ampere current flows through the conductor. As the conductor is made thinner, the resistance of the conductor By keeping the potential difference constant and the resistance is doubled, then V = IR I = V/R Then, I ∝ 1/R Therefore, when R is doubled, I becomes
- ScienceClass 10ICSE
What is meant by the “resistance of a conductor”? Write the relation between resistance, potential difference, and current. b) When a 12V battery is connected across an unknown resistor, there is a current of 2.5mA in the circuit. Calculate the value of the resistance of the resistor.
Resistance of a conductor is the property of a This property helps conductor in opposing the flow of current through it. Work done = potential difference × charge moved Given, Voltage, V = 12 volt Current, I = 2.5 × 10-3A We know that, V = IR R = V/I R = 12/2.5 × 10-3 R = 4.8 × 103ohm = 4800 ohm
- ScienceClass 10ICSE
What is Ohm’s law? Explain how it is used to define the unit of resistance.
Ohm’s law helps in understanding the relation between current, I and potential difference, V. The law states that at constant temperature, the current flowing through a conductor is directly proportional to the potential difference across its ends. The mathematical representation of the law is: Let I be the current flowing through a conductor and V be the potential difference across the ends of the conductor. Then from Ohm’s law we know that I ∝ V V ∝ I V
- ScienceClass 10ICSE
Classify the following into good conductors, resistors, and insulators: Rubber, mercury, nichrome, polythene, aluminium, wood, manganin, bakelite, iron, paper, thermocol, metal coin
Conductor: mercury, aluminium, iron, metal coin Resistor: manganin, nichrome Insulator: rubber, polythene, wood, bakelite, paper, thermocol
- ScienceClass 10ICSE
Distinguish between good conductors, resistors, and insulators. Name two conductors, two resistors, and two insulators.
The difference between good conductors, resistors, and insulators are as follows: The materials that are having less or low electrical resistance are known as good conductors. Copper and iron are the two examples of good conductors. The materials that are having comparatively high resistance are known as resistors. Manganin and nichrome are the two examples of resistors. The materials that are having infinitely high resistance are known as insulators. Wood and rubber a
- ScienceClass 10ICSE
Fill in the following blanks with a suitable word: Ohm’s law states a relation between potential difference and ……
Ohm’s law states a relation between potential difference and current.
- ScienceClass 10ICSE
. A current of 5 amperes flows through a wire whose ends are at a potential difference of 3 volts. Calculate the resistance of the wire.
Given, Current, I = 5A Potential difference, V = 3V We know that, V = IR Therefore, 3 = 5 × R R = 3/5 = 0.6 Ohms
- ScienceClass 10ICSE
A resistance of 20 ohms has a current of 2 amperes flowing in it. What potential difference is there between its ends?
Given, Resistance, R = 20 Ohms Current, I = 2 amp We know that, V = IR Therefore, V = 2 × 20 = 40V
- ScienceClass 10ICSE
A potential difference of 20V is applied across the ends of a resistance of 5 ohms. What current will flow in the resistance?
Given, Potential difference, V = 20V Resistance, R = 5 Ohms Current, I = ? We know that, V = IR 20 = I × 5 I = 20/5 = 4A
- ScienceClass 10ICSE
Keeping the potential difference constant, the resistance of a circuit is halved. By how much does the current change?
Given, Potential difference = constant Also, we know that, V = IR I = V/R Given that V is constant, therefore, I will be proportional to 1/R. Therefore, when R is halved, I also becomes double.
- ScienceClass 10ICSE
Which has less electrical resistance: a thin wire or a thick wire of the same length and same material?
A thick wire with the same length and same material as that of a thin wire will have less electrical resistance because the number of electrons present in the thick wire is more than the thin wire.