Question

A resistor has a resistance of 176 ohms. How many of these resistors should be connected in parallel so that their combination draws a current of 5 amperes from a 220 volt supply line?

Answer 1

Suppose x resistors should be connected in parallel to draw a current of 5 A.
For a parallel combination, 1 / R = 1 / R₁ + 1 / R₂ + 1 / R₃ + ... (x times)

Here, R₁ = R₂ = R₃ = ... = 176 Ω
Then the resultant resistance, R = 176 / x Ω

Given that the current, I = 5 A and voltage, V = 220 V

Then by Ohm's law, V = IR

By substituting the values, we get:

`220=5xx176/x`

x = 4

Hence, four resistors of 176 Ω each should be connected in parallel to draw a current of 5 A from a 220 V supply line.