Electricity: Class 10 Science Q&A · Page 7
281 free answers on Electricity (Science) for Class 10 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- ScienceClass 10ICSE
What happens to the other bulbs in a parallel circuit if one bulb blows off?
When the bulbs are in parallel, they continue to glow.
- ScienceClass 10ICSE
What happens to the other bulbs in a series circuit if one bulb blows off?
When the bulbs are connected in series, all the other bulbs stop glowing.
- ScienceClass 10ICSE
Are the lights in your house wires in series?
The light in our houses are not connected in series. They are connected in parallel.
- ScienceClass 10ICSE
A wire of resistance R1 is cut into five equal pieces. These five pieces of wire are then connected in parallel. If the resultant resistance of this combination be R2, then the ratio R1/R2 is: a) 1/25 b) 1/5 c) 5 d) 25
The correct option is d) 25. When a resistance wire is cut into five pieces, the ratio of the resistance and the resultant resistance obtained when the pieces are connected in parallel is 25.
- ScienceClass 10ICSE
If this arrangement of three resistors was to be replaced by a single resistor, its resistance should be: a) 9Ω b) 4 Ω c) 6 Ω d) 18 Ω
The correct option is a) 9 Ω Again series and parallel combination is used for the calculation of overall resistance of the given circuit.
- ScienceClass 10ICSE
If two resistors of 25 Ω and 15 Ω are joined together in series and then placed in parallel with a 40 Ω resistor, the effective resistance of the combination is: a) 0.1 Ω b) 10 Ω c) 20 Ω d) 40 Ω
The correct option is c) 20 Ω The resultant resistance obtained from the resistors that are placed in series combination is connected with 40 Ω in parallel such that the overall resistance obtained is equal to 20 Ω.
- ScienceClass 10ICSE
A 4 Ω coil and a 2 Ω coil are connected in parallel. What is their combined resistance? A total current of 3A passes through the coils. What current passes through the 2 Ω coil?
4 Ω and 2 Ω coils are connected in parallel. Therefore, the combined resistance, R 1/R = ¼ + ½ = ¾ R = ¾ Ω Total current,, I = V/R = 3 Ω V/(4/3) = 3 V = 4V Current through 2 Ω coil = V/2 = 4/2 = 2 A
- ScienceClass 10ICSE
A potential difference 6V is applied to two resistors of 3 Ω and 6 Ω connected in parallel. Calculate: a) the combined resistance b) the current flowing in the main circuit the current flowing in the 3 Ω resistor
Given, V = 6V R1 = 3 Ω R2 = 6 Ω Combined resistance, 1/R = 1/R1 + 1/R2 = 1/3 + 1/6 = ½ R = 2 Ω Current flowing in the main circuit, I = V/R = 6/2 = 3A Current flowing in 3 Ω resistor = V/R1 = 6/3 = 2A
- ScienceClass 10ICSE
A potential difference of 4V is applied to two resistors of 6Ω and 2 Ω connected in series. Calculate: a) the combined resistance b) the current flowing the potential difference across the 6 Ω resistor
Given, V = 4V R1 = 6 Ω R2 = 2 Ω Combined resistance, R = R1 + R2 = 8 ohm Current flowing, I = V/R = 4/8 = 5 amp Potential difference across 6 ohm resistor = IR1 = 3V
- ScienceClass 10ICSE
An electric heater which is connected to a 220V supply line has two resistance coils A and B of 24 ohm resistance each. These coils can be used separately in series or in parallel. Calculate the current drawn when: a) only one coil A is used b) coils A and B are used in series coils A and B are used in parallel
Given, V = 220V Ra = Rb = 24 ohm a) Current drawn when only coil A is used: I = V/Ra = 220/24 = 9.16 amps b) Current drawn when the coils A and B are used in series: Total resistance, R = Ra + Rb = 24 + 24 = 48 ohms I = V/R = 220/48 = 4.58 amps c) Current drawn when coils A and B are used in parallel: Total resistance is 1/R = 1/Ra + 1/Rb = 1/24 + 1/24 = 2/24 = 1/12 R = 12 ohms I = V/R = 220/12 = 18.33 amps
- ScienceClass 10ICSE
A resistor has a resistance of 176 ohms. How many of these resistors should be connected in parallel so that their combination draws a current of 5 ampere from a 220 volt supply volt line?
I = 5 amp V = 220 V R = V/I = 220/5 = 44 ohm The resultant resistance must be less than 176 ohm. Therefore, the resistors are connected in parallel Let the required no be n Rre = 176/n = 44 N = 176/44 = 4
- ScienceClass 10ICSE
Two resistors with resistances 5 Ω and 10 Ω respectively are to be connected to a battery of emf 6V so as to obtain minimum and maximum current flowing a) How will you connect the resistances in each case? Calculate the strength of the total current in the circuit in the two cases.
Given, R1 = 5 Ω R2 = 10 Ω V = 6V When the two resistors are connected in series, minimum current flows through the When the resistors are connected in parallel, the current flow will be maximum. When the resistors are in series, Total resistance = 5 + 10 = 15Ω 1/R = 1/R1 + 1/R2 1/R = 1/5 + 1/10 1/R = 3/10 R = 10/3 Ω Therefore, the total current drawn by the circuit = V/R = 6/(10/3) = 1.8amps
- ScienceClass 10ICSE
A battery of 9V is connected in series with resistors of 0.2Ω, 0.3 Ω, 0.4 Ω, 0.5 Ω, and 12 Ω. How much current would flow through the 12 Ω resistor?
Given, R1 = 0.2 Ω R2 = 0.3 Ω R3 = 0.4 Ω R4 = 0.5 Ω R5 = 12 Ω V = 9V Therefore, the resultant resistance is given as: R = R1 + R2 + R3 + R4 + R5 = 0.2 + 0.3 + 0.4 + 0.5 + 12 = 13.4 Ω The current flow through 12 Ω resistance is given as: V/R Therefore, I = 9/13.4 I = 0.67amp
- ScienceClass 10ICSE
Show how you would connect two 4 ohm resistors to produce a combined resistance of a) 2 ohms 8 ohms
By connecting in parallel, then 1/R = ¼ + ¼ = 2/4 = ½ Therefore, R = 2 ohm By connecting in series, then R = 4 + 4 = 8 Therefore, R = 8 ohm
- ScienceClass 10ICSE
What possible values of resultant resistance one can get by combining two resistances, one of value 2 ohm and the other 6 ohm?
R1 = 2 Ohm R2 = 6 Ohm Let case 1 be parallel combination 1/R = 1/R1 + 1/R2 1/R = ½ + 1/6 = 4/6 R = 6/4 = 1.5 ohm Let case 2 be series combination R = R1 + R2 = 2+6 = 8 ohm
- ScienceClass 10ICSE
Two resistances X and Y are connected turn by turn: a) in parallel b) in series. In which case the resultant resistance will be less than either of the individual resistances?
When the two resistance X and Y are connected in parallel, the resultant resistance will be less than either of the individual resistances.
- ScienceClass 10ICSE
How should the two resistances of 2 ohms each be connected so as to produce an equivalent resistance of 1 ohm?
To produce an equivalent resistance of 1 ohm, the two resistances of 2 ohms must be connected in parallel.
- ScienceClass 10ICSE
If 3 resistances of 3 ohm each are connected in parallel, what will be their total resistance?
R1 = R2 = R3 = 3Ω 1/R = 1/R1 + 1/R2 + 1/R3 = 1/3 + 1/3 + 1/3 = 3/3 = 1 Therefore, R = 1Ω
- ScienceClass 10ICSE
State the law of combination of resistance in parallel.
According to the law of combination of resistance in parallel, the reciprocal of the combined resistance of a number of resistances connected in parallel is equal to the sum of the reciprocals of all the individual resistances.
- ScienceClass 10ICSE
If five resistances each of value 0.2 ohm are connected in series, what will be the resultant resistance?
According to the law of combination of resistances in series, R = R1 + R2 + R3 + R4 + R5 R = 0.2 + 0.2 + 0.2 + 0.2 + 0.2 = 1 ohm