Advertisements
Advertisements
प्रश्न
Show how would you join three resistors, each of resistance 9 Ω so that the equivalent resistance of the combination is
1) 13.5
2) 6 Ω
Advertisements
उत्तर
1) Case: To get equivalent resistance = 13.5 Ω
For this case, two 9 Ω resistors should be first connected in parallel and then their combination should be connected in series with the remaining 9 Ω resistor. Thus,
`R = (9xx9)/(9+9) = 81/18` = 4.5 Ω
`R_"total"` = R + 9 = 4.5 + 9 = 13.5 Ω
2) Case: To get equivalent resistance = 6 Ω
For this case, two 9 Ω resistors should be first connected in series and then this combination should be connected in parallel with the remaining 9 Ω resistor. Thus,
R1 = 9 + 9 = 18 Ω
`R_"total" = (R_1xxR)/(R_1+R) = (18xx9)/(18+9)` = 6 Ω
APPEARS IN
संबंधित प्रश्न
Show how you would connect two 4 ohm resistors to produce a combined resistance of (a) 2 ohms (b) 8 ohms.
An electric heater which is connected to a 220 V supply line has two resistance coils A and B of 24 Ω resistance each. These coils can be used separately (one at a time), 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.
(c) coils A and B are uses in parallel.
A 4 Ω coil and a 2 Ω coil are connected in parallel. What is their combined resistance? A total current of 3 A passes through the coils. What current passes through the 2 Ω coil?
Two exactly similar electric lamps are arranged (i) in parallel, and (ii) in series. If the parallel and series combination of lamps are connected to 220 V supply line one by one, what will be the ratio of electric power consumed by them?
You have three resistors of values 2Ω, 3Ω and 5Ω. How will you join them so that the total resistance is less than 1Ω? Draw diagram and find the total resistance.
Explain, why is the p.d. between the terminals of a storage battery less when it is supplying current than when it is on open circuit. A battery of e.m.f. 10 volts and internal resistance 2.5 ohms has two resistances of 50 ohms each connected to it. Calculate the power dissipated in each resistance
(a) When they are in series,
(b) When they are in parallel.
In each case calculate the power dissipated in the battery.
Solve the following question:
In an electric circuit, two resistors of 12 0 each are joined in parallel to a 6 V battery. Find the current drawn from the battery.
State the S.I. unit of electrical resistance and define it.
A given wire is stretched to double its length. How will its resistance change?
The diagram above is a schematic diagram of a household circuit. The house shown in the above diagram has 5 usable spaces where electrical connections are made. For this house, the mains have a voltage of 220 V and the net current coming from the mains is 22A.
- What is the mode of connection to all the spaces in the house from the mains?
- The spaces 5 and 4 have the same resistance and spaces 3 and 2 have respective resistances of 20Ω and 30Ω. Space 1 has a resistance double that of space 5. What is the net resistance for space 5.
- What is the current in space 3?
- What should be placed between the main connection and the rest of the house’s electrical appliances to save them from accidental high electric current?
