Advertisements
Advertisements
प्रश्न
A wire that has resistance R is cut into two equal pieces. The two parts are joined in parallel. What is the resistance of the combination?
Advertisements
उत्तर
A wire that has a resistance, R is cut into two equal pieces.
The resistance of the each piece will be `R/2`
The two parts, each of resistance, R/2 are joined in parallel.
The resistance of the parallel combination:
`1/R^rho=1/R=1/R_1+1/R_2`
`Here R^1=R/2`
`=R_2=R/2`
`1/Rrho=1/(R/2)+1/(R/2)`
`1/Rrho=2/R+2/R`
`1/Rrho=4//R`
`Rrho=R/4`
Thus, the resistance of the combination will be R/4.
APPEARS IN
संबंधित प्रश्न
How many 176 Ω resistors (in parallel) are required to carry 5 A on a 220 V line?
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistances, which may be used separately, in series, or in parallel. What are the currents in the three cases?
Find the current in each resistor in the circuit shown below:
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?
Explain with the help of a labelled circuit diagram, how you will find the resistance of a combination of three resistors of resistances R1, R2 and R3 joined in parallel.
Are the lights in your house wired in series?
If current flows through two lamps arranged:
(a) in series,
(b) in parallel,
and the filament of one lamps breaks, what happens to the other lamp? Explain your answer.
In parallel combination of resistances ______.
Four resistors each of resistance 2Ω are connected in parallel. What is the effective resistance?
A uniform wire with a resistance of 27 Ω is divided into three equal pieces and then they are joined in parallel. Find the equivalent resistance of the parallel combination.
Show how would you connect three resistors, each of resistance 6 O so that
the combination has a resistance of(a) 9 Ω (b) 4 .Ω
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.
How does the resistance of a metallic wire depend on the thickness of wire?
What connection is used in domestic appliances and why?
Three resistors of 1 Ω, 2 Ω and 3 Ω are connected in parallel. The combined resistance of the three resistors should be:
A piece of wire of resistance R is cut into three equal parts. These parts are then connected in parallel. If the equivalent resistance of this parallel combination is R1, what is the value of the ratio R1 : R?
Study the following circuit:
On the basis of this circuit, answer the following questions:
i. Find the value of total resistance between the points A and B.
ii. Find the resistance between the points B and C.
iii. Calculate the current drawn from the battery, when the key is closed
OR
iii. In the above circuit, the 16Ω resistor or the parallel combination of two resistors of 8 Ω, which one of the two will have more potential difference across its two ends? Justify your answer.
Two resistors having resistance 8 Ω and 12 Ω are connected in parallel. Find their equivalent resistance.
Two resistors of resistances 2 Ω and 3 Ω are connected in parallel to a cell to draw current 0.5 A from the cell. Draw a labelled diagram of the arrangement
A particular resistance wire has a resistance of 3·0 ohm per metre. Find the resistance of 5 m length of a wire of the same material, but with twice the area of cross section.
