Question

An electric heater is operated by applying a potential difference of 78.0 V across a nichrome wire of total resistance 7.00 Ω. a) Find the current in the wire. Answer in units of A.
b) Find the power rating of the heater. Answer in units of W.

Answer 1

PART A)

Here we know that

potential difference across the wire is

$V = 78 volts$

resistance of wire is

$R = 7 ohm$

now by ohm's law

$V = iR$

$78 = i(7 ohm)$

$i = 11.14 A$

Part b)

Power rating is defined as rate of electrical energy

it is defined as

$P = iV$

now we have

$P = 11.14 ( 78)$

$P = 869.1 Watt$