Question
Physics Question on Conservation of energy
On giving 220 V to a resistor the power dissipated is 40 watt, then the value of resistance is:
A
(A) 1210 Ω
B
(B) 2000 Ω
C
(C) 1000 Ω
D
(D) None of these
Answer
(A) 1210 Ω
Explanation
Solution
Explanation:
Given:Potential difference (V)=220VPower of the bulb (P)=40WWe know that:The rate at which electrical energy is dissipated into other forms of energy is called electrical power i.e.,P=Wt=VI=I2R=V2RWhere, V= Potential difference, R= Resistance and I= current.The resistance can be calculated as,R=V2P=(220)240=1210ΩHence, the correct option is (A).