Question

On giving 220 V to a resistor the power dissipated is 40 watt, then the value of resistance is:

• (A) 1210 Ω
• (B) 2000 Ω
• (C) 1000 Ω
• (D) None of these

Answer 1

The Correct Option is A

Explanation:
Given:Potential difference $(V)=220V$Power of the bulb $(P)=40W$We know that:The rate at which electrical energy is dissipated into other forms of energy is called electrical power i.e.,$P=\frac{W}{t}=VI=I^{2}R=\frac{V^2}{R}$Where, $V=$ Potential difference, $R=$ Resistance and $I=$ current.The resistance can be calculated as,$R=\frac{V^2}{P}=\frac{(220{)}^2}{40}=1210\mathrm{\Omega }$Hence, the correct option is (A).