Question

An electric heater draws a current of 5 ampere from 220 volt supply.Calculate

(a) its resistance.
(b) electrical energy consumed in kwh if it is used for 4 hours​

Answer 1

`\bf \underline{Given :-}`

`\sf{• \: An  \: electric \:  heater \:  draws  \: a  \: current  \: of  \: 5  \: ampere \:  from \:  220  \: volt \:  supply.}`

`\\`

`\bf{ \underline{To \:  Find:- }}`

`\sf• \: ( a)  \: lts  \: resistance.`

`\sf• \: (b) \:  electrical  \: energy  \: consumed  \: in \:  kwh \:  if  \: it  \: is  \: used  \: for \:  4  \: hours.`

`\\`

`\huge\bf{ \underline{ Solution :-}}`

`{ \boxed{\bf{(a)}}}`

`\sf•  \: Current  \: (I) = 5 \: A`

`\sf• \: Voltage \: (V) = 220 \: v`

`\bf \red{\bigstar{\: Formula \:  of \:  Resistance \: (R) =  (V)/(I) }}`

`\sf \rightarrow  R = (220)/(5)`

`\sf \rightarrow R =44`

`\bf{Hence,  \: it's  \: resistance \:  is  \:  \: 44 \:  Ω \: .}`

`\\  \\`

`{ \boxed{\bf{(b)}}}`

`\sf•  \: Current  \: (I) = 5 \: A`

`\sf• \: Voltage \: (V) = 220 \: v`

`\bf \red{\bigstar{\: Formula  \: of \:  Electric  \: Power \:  (P) = IV  }}`

`\sf \rightarrow P = (5  * 220)`

`\sf \rightarrow P = 1100 \:`

`\\`

`\sf \therefore \: P = 1100 \: watt`

`\sf{• \: Time  \: (t) = 4  \: hours }`

`\bf \red{\bigstar{ \: Formula  \: of  \: Energy  \: (W) = Pt}}`

`\sf \rightarrow W= 1100  *  4`

`\sf \rightarrow W = 4400`

`\sf \rightarrow W  =  (4400)/(1000)`

`\sf \rightarrow W  =  4.4`

`\sf \therefore W  =  4.4 \: kwh`

`\bf{Hence,  \: Electrical  \: Energy \:  is \:  4.4  \: kwh.}`