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

I=5amp

V=220volt

t=2h

'P=?,E=?

We know that,

P=V×I

=220×5

=1100watt

=1.1kW

Energy consumed , E=P×t

=1.1×2

=2.2kWh

Answer 2

$\bf \underline{Given :-}$

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

$\bf{ \underline{To \:  Find:- }}$

$\sf• \: ( a) \: lts \: resistance.$

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

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

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

$\sf• \: Current \: (I) = 5 \: A$

$\sf• \: Voltage \: (V) = 220 \: v$

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

$\sf \rightarrow R = \frac{220}{5}$

$\sf \rightarrow R =44$

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

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

$\sf• \: Current \: (I) = 5 \: A$

$\sf• \: Voltage \: (V) = 220 \: v$

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

$\sf \rightarrow P = (5 \times 220)$

$\sf \rightarrow P = 1100 \:$

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

$\sf{• \: Time \: (t) = 4 \: hours }$

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

$\sf \rightarrow W= 1100 \times 4$

$\sf \rightarrow W = 4400$

$\sf \rightarrow W = \frac{4400}{1000}$

$\sf \rightarrow W = 4.4$

$\sf \therefore W = 4.4 \: kwh$

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