Question

One heater uses 490 W of power when connected by itself to a battery. Another heater uses 250 W of power when connected by itself to the same battery. How much total power do the heaters use when they are both connected in series across the battery?

Answer 1

Power will be 166.66 watt when the heater are connected in series

Step-by-step explanation:

We have given power of the first heater
`P_1` = 490 watt

And power of the second heater
`P_2` = 250 watt

We know that in series connection potential difference will be same

So let the potential difference is v

Power is given by
`P=(V^2)/(R)`

So
`490=(V^2)/(R_1)`

`R_1=(V^2)/(490)=0.0020V^2`

Similarly
`R_2=(V^2)/(250)=0.04V^2`

As resistances are connected in series so equivalent resistance
`R=R_1+R_2=0.0020V^2+0.04V^2=0.006V^2`

So power
`P=(V^2)/(R)=(V^2)/(0.006V^2)=166.66Watt`