Question

An electric lamp of 200 ohm and a toaster of 100 ohm are connected in parallel to a 220 V
electricity source.
(a) What will be the resistance of an electric iron which when connected to the same
electric source permits the same current as the total current flowing through both
the appliances described above ?
(b) What is the current passing through the electric iron ?
(c) Calculate the power of the electric iron.​

Answer 1

Resistence1 of electric lamp-200 ohm

Resistence2 of toaster= 100 ohm

Voltage (V) of the source= 220 V

As they r conectd in parallel the resistnce will be given by : R= 1/R1+1/R2

where R is the total resistence

R= 1/200 +1/100 ( lcm of 100 and 200 is 200)

R = 200/3  

By applyinh ohms law V=IR  

I=V/R

220/ 200/3 = 220*3/200 = 33/10=3.3A

So 3.3 is the current drawn by both elecrtical appliances

So current drawn by the electrc iron is 3.3A

Whr ( A) is the S.I unit for current

Hope it helpz u !!

Answer 2

Answer:

a) 66.7Ω b) 3.3A c) 726W

Explanation:

a) R = 1/200 + 1/100

R = 200/3 = 66.7Ω

let it be 200/3 to make calculation easier

b) V = IR. (ohm's law)

I = V/R

220/200/3 = I

3.3 A = I

c) P = I²R

3.3² × 200/3

10.89 × 200/3

3.63×200 = 726W