How many 176 Ω resistors (in parallel) are required to carry 5 A on a 220 V line?
Given: Resistance of each resistor, R = 176 Ω; Current, I = 5 A; Voltage, V = 220 V.
Step 1: Calculate equivalent resistance needed using Ohm's law: R_eq = V/I = 220 V / 5 A = 44 Ω.
Step 2: For n resistors of equal resistance R in parallel, the equivalent resistance is R_eq = R/n. Solving for n: 44 = 176/n, therefore n = 176/44 = 4.
Answer: 4 resistors of 176 Ω each connected in parallel are required to carry 5 A on a 220 V line.
Explanation
This is a numerical problem from the NCERT textbook about parallel resistors. Using Ohm's law, we first find the equivalent resistance needed (44 Ω), then apply the parallel resistance formula to find that 4 resistors of 176 Ω each are needed.
Solution Steps
Step 1: Calculate equivalent resistance needed using Ohm's law: R_eq = V/I = 220 V / 5 A = 44 Ω
Step 2: For n resistors of equal resistance R in parallel, the equivalent resistance is R_eq = R/n
Step 3: Solve for n: 44 = 176/n, therefore n = 176/44 = 4