Advertisements
Advertisements
Question
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?
Solution
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
RELATED QUESTIONS
Complete the following :-
(c)
An electric lamp of 100 Ω, a toaster of resistance 50 Ω, and a water filter of resistance 500 Ω are connected in parallel to a 220 V source. What is the resistance of an electric iron connected to the same source that takes as much current as all three appliances, and what is the current through it?
What are the advantages of connecting electrical devices in parallel with the battery instead of connecting them in series?
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?
The equivalent resistance of the parallel combination of two resistors of 60Ω and 40Ω is _______.
A) 24Ω
(B) 100Ω
(C) 50 Ω
(D) 240Ω
Which of the following arrangement, A or B, has the lower combined resistance?
State how are the two resistors joined with a battery when potential difference is same across each resistor.
Which of the following combinations have the same equivalent resistance between X and Y?
Two V-I graphs A and B for series and parallel combinations of two resistors are as shown. Giving reason state which graph shows (a) series, (b) parallel combination of the resistors.
