Advertisements
Advertisements
प्रश्न
How many 176 Ω resistors (in parallel) are required to carry 5 A on a 220 V line?
उत्तर
Suppose n resistors of resistance 176 Ω are connected in parallel.
Therefore, the value of equivalent resistance (Rp) will be:
`1/"R"_"p" = 1/176 + 1/176 + ... + "n"`
`1/"R"_"p" = "n". (1/176)`
Rp = `176/"n"` Ω ......(1)
Given, V = 220 V and I = 5 A
∴ According to Ohm's law: Rp = `"V"/"I"`
= `220/5`
= 44 Ω
By substituting the value of Rp in equation (1), we get:
44 = `176/"n"`
n = `176/44`
n = 4
Hence, the number of resistors (n) is 4.
APPEARS IN
संबंधित प्रश्न
Complete the following :-
(b)
What are the advantages of connecting electrical devices in parallel with the battery instead of connecting them in series?
How can three resistors of resistances 2 Ω, 3 Ω and 6 Ω be connected to give a total resistance of 4 Ω ?
The equivalent resistance of the parallel combination of two resistors of 60Ω and 40Ω is _______.
A) 24Ω
(B) 100Ω
(C) 50 Ω
(D) 240Ω
Show how you would connect two 4 ohm resistors to produce a combined resistance of (a) 2 ohms (b) 8 ohms.
State how are the two resistors joined with a battery when equivalent resistance is less than either of the two resistances.
In parallel combination of resistances ______.
Which of the following combinations have the same equivalent resistance between X and Y?
Four resistors each of resistance 2Ω are connected in parallel. What is the effective resistance?
In the following figure calculate:
- the total resistance of the circuit
- the value of R, and
- the current flowing in R.
A battery of e.m.f 16 V and internal resistance 2 Ω is connected to two resistors 3Ω and 6Ω connected in parallel. Find:
- the current through the battery.
- p.d. between the terminals of the battery,
- the current in 3 Ω resistors,
- the current in 6 Ω resistor.
The circuit diagram Fig shows three resistors 2 Ω, 4 Ω and R Ω connected to a battery of e.m.f. 2 V and internal resistance 3 Ω. If main current of 0.25 A flows through the circuit, find:
- the p.d. across the 4 Ω resistor,
- the p.d. across the internal resistance of the cell,
- the p.d. across the R Ω or 2 Ω resistors
- the value of R.
Two resistors of resistance 4 Ω and 6 Ω are connected in parallel to a cell to draw 0.5 A current from the cell.
Calculate current in each resistor.
A coil in the heater consumes power P on passing current. If it is cut into halves and joined in parallel, it will consume power:
Three resistors of 1 Ω, 2 Ω and 3 Ω are connected in parallel. The combined resistance of the three resistors should be:
Assertion: When a battery is short circuited, the terminal voltage is zero.
Reason: In a short circuit, the current is zero.
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?
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
